Copyright by Paul Derrick. Permission is granted for free electronic distribution as long as this paragraph is included. For permission to publish in any other form, please contact the author at firstname.lastname@example.org.
Stargazer Columns 2005
Dec. 31, 2005: Space Exploration in 2006
Dec. 17, 2005: The Star of Bethlehem
Dec. 3, 2005: Winter's Long Night Moon
Nov. 19, 2005:Measuring Time Before Clocks and Calendars
Nov. 5, 2005: Invasion of the Martians, or Maybe the Europans?
Oct. 22, 2005: Here Comes Mars -- Really This Time
Oct. 8, 2005: Mars As Big As the Full Moon?
Sep. 24, 2005: Science and Religion In Conflict?
Sep. 10, 2005: Saturn Stirs Up a Beehive
Aug. 27, 2005: Venus and Jupiter Together at Dusk
Aug. 13, 2005: The Fox's Swan Song
Jul. 30, 2005: Time for the Annual Perseid Meteor Shower
Jul. 16, 2005: Two Ways of Looking at Constellations
Jul. 2, 2005: Is Mars Really Coming Close or Not?
Jun. 18, 2005: Planetary Meeting and Seeing Comet Tempel
Jun. 4, 2005: Mission: Deep Impact
May 21, 2005: Telling Planets from Stars
May 9, 2005: Using Mars to Find Uranus
Apr. 23, 2005: Spring Means Cosmic Baseball
Apr. 9, 2005: The Age of Aquarius?
Mar. 26, 2005: Partial Solar Eclipse to be Visible Here
Mar. 12, 2005: Albert Einstein
Feb. 26, 2005: The Moon Hides Antares
Feb. 12, 2005: Pluto Discovered 75 Years Ago This Month
Jan. 29, 2005: Future of Hubble Space Telescope in Jeopardy
Jan. 15, 2005: 2005 Stargazing Highlights
Jan. 1, 2005: Comet Machholz Greets the New Year
December 31, 2005
Space Exploration in 2006
If all goes as planned 2006 will be an exciting year for space exploration as six missions are scheduled to begin, end, or achieve a milestone.
Stardust returns Jan. 15 from its encounter with Comet Wild-2. Having already sent images and other data, its main mission was to fly through the comet's tail, gather particles of cometary dust, and return them to Earth for up-close study. Scientists hope to learn more about the origin of comets, and thus more about star and planet formation. [stardust.jpl.nasa.gov]
NASA officials may be watching with more than normal anxiety. In Sept. 2004 the Genesis spacecraft, attempting to soft land with solar particles, crash landed, so keep your fingers crossed.
One of the most exciting missions in years is New Horizons, to be launched between Jan. 17 and Feb. 14 on a long journey to the last unexplored planet, Pluto. If launched before Feb. 3, it will fly by Jupiter in 2007, get a gravitational speed-boost, and reach Pluto in 2015. A later launch, missing the Jupiter boost, will add five years to the trip. [pluto.jhuapl.edu]
In March the Mars Reconnaissance Orbiter will begin orbiting Mars for a 2-year study expected to double our knowledge about our intriguing neighbor. [mars.jpl.nasa.gov/mro]
In April the Venus Express will begin orbiting and studying our other planetary neighbor. [www.esa.int/SPECIALS/Venus_Express]
Also in April Stereo, a pair of spacecraft designed to study the Sun, will be launched. With one craft orbiting ahead of Earth and the other behind it, the pair will enable stereoscopic (3-D) study of solar events like sunspots, flares, prominences and other solar eruptions. [stereo.gsfc.nasa.gov]
Finally June will see the launch of Dawn to the asteroid belt. It will spend 7 months studying Vesta in 2011, and then go to the largest asteroid, Ceres, reaching it in 2015. [dawn.jpl.nasa.gov]
- Next Two Weeks: Average sunrise: 7:29 a.m.; average sunset: 5:41 p.m. (for Waco, TX)
* Tomorrow evening (Jan. 1) a thin crescent Moon is to the left of Venus low in the west at dusk.
* Tuesday morning (Jan. 3) the Quadrantid meteor shower peaks in Bootes with the best viewing from 1 a.m. to dawn.
* Wednesday (Jan. 4) Earth reaches perihelion, when it is nearest the Sun (91.2 million miles) in its elliptical orbit.
* The Moon is at 1st quarter Friday (Jan. 6).
* The evening of Jan. 8 the Moon is to the upper left of Mars high in the south.
* The mornings of Jan. 9-17 Jupiter is very near Libra's brightest star 3rd-magnitude star Zubenelgenubi, a binocular double star.
* The evening of Jan. 9 a bright gibbous Moon passes through the Pleiades (Seven Sisters) star cluster, but its glare will make it difficult seeing the lovely cluster.
- Naked-eye Planets: (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Mercury spends early Jan. in the morning sky near the eastern horizon but quickly sinks into the Sun. Venus, low in west at dusk, is about to sink into the setting Sun. Mars, high in the south in the evening, is still bright but growing fainter nightly. Jupiter, rising after midnight, is in the southeast by morning. Saturn rises soon after sunset and is up all night.
- Advance Notice: The Central Texas Astronomical Society will host their annual "Learn to Use Your Telescope" star party Jan. 21, 5-8 p.m., at Hewitt City Park. Bring your new telescope for free hands-on instruction from experienced stargazers.
December 17, 2005
The Star of Bethlehem
This is the time of year amateur astronomers are often asked about the star of Bethlehem. Might it have been a comet, a supernova, a planetary conjunction? The following adaptation of a 1998 Stargazer column gives my response.
This question can be touchy as it involves deeply held religious beliefs shared by many, some of whom don't even appreciate the question. To those who believe the story involved a miracle--an event outside the laws of nature--it is senseless to seek an astronomical explanation.
Astronomy, like all other sciences, is based on the premise that all events occur within the laws of nature. Few scientists, therefore, would offer a miraculous explanation. Many people, like those asking the question, believe the star existed as a natural event--either mysteriously coincidental with Jesus' birth or simply something ascribed special meaning at the time.
Computer programs can simulate the night sky for virtually any date in history, so with a firm date of birth for Jesus we could search for things like unusually close pairings of planets with other planets or bright stars, or the approach of known periodic comets. Unfortunately, the date is not known, and even if it was such programs can't show everything, like supernovae, one-time-only comets and other ephemeral events. There is also the enigma of a star in the east leading men to a destination in the west.
Many Christians and non-Christians, including me, believe the star of Bethlehem story is apocryphal--part of the lore of the Jesus story but not a real historical event. Seeking to identify it with an actual astronomical occurrence might be akin to looking for Dorothy's Yellow Brick Road somewhere in Kansas.
So, what was the star of Bethlehem? Astronomy simply can't say, nor can it confirm or refute the story. Regardless, the Stargazer wishes you and yours a season of love and peace shared with family and friends.
- Next Two Weeks: Average sunrise: 7:25 a.m.; average sunset: 5:31 p.m. (for Waco, TX)
* Tomorrow evening (Dec. 18) after they rise around 9 p.m., the Moon and Saturn travel together across the sky and by morning are high in the west.
* Monday (Dec. 19) is the ancient Roman festival, Saturnalia, honoring the Roman god Saturn, father of Jupiter.
* Wednesday (Dec. 21) is the first day of winter.
* The Moon is at 3rd quarter Friday (Dec.23).
* The morning of Dec. 25, the crescent Moon is near the star Spica high in the southeast, and the next two mornings, above, then below, Jupiter.
* The morning of Dec. 29 a thin crescent Moon is to the upper right of Mercury near the southeastern horizon 45 minutes before sunrise. Binoculars may be needed.
* The Moon is new Dec. 30.
- Naked-eye Planets: Venus, the hard-to-miss "evening star" in the west, sets 3 hours after sunset. Mars still dominates the evening southeastern sky. Saturn, up by 9 p.m., is high in the southwest by morning, and Jupiter is up by 4 a.m. Mercury is low in the southeast before sunrise.
- Astro Milestones: Dec. 25 is the birthday of Isaac Newton (1642-1727), father of modern physics, and Dec. 27 is the birthday of Johannes Kepler (1571-1630), discoverer of elliptical orbits.
- Stargazer Book: A Beginner's Guide to Learning the Night Sky by Paul Derrick would make a great gift for that stargazer in your life. Click here for more about my books and ordering.
December 3, 2005
Winter's Long Night Moon
The December full Moon, falling this year on the 15th, is called the Moon Before Yule and the Long Night Moon. Full Moon names derive from different cultures and there is no official list, but the origins of most are easy to understand--like fall's Harvest Moon which comes as crops are being harvested.
The meaning of Moon Before Yule is clear enough--this is the full Moon just before Yule, originally a midwinter pagan festival but now usually referring to Christmas.
The meaning of Long Night Moon is slightly less obvious. At the Dec. 21 winter solstice, days are shortest and nights longest, so the nearest full Moon would fall on one of the year's longest nights. But the name might have meant more to its originators.
The Moon is full (fully illuminated by the Sun) when it is on opposite side of Earth from the Sun. Thus full Moons always rise around sunset, stay up all night and set around sunrise.
Owing to Earth's tilt on its axis, the length of the day--that is, the time the Sun is up--changes throughout the year. The day is longest at summer solstice when, in our part of the world, the Sun is up more than 14 hours, and shortest at winter solstice when it is up only 10 hours. The Moon is just the opposite.
The planets orbit the Sun, and the Moon orbits Earth, on nearly the same plane, so the Sun, Moon and planets all roughly follow the same path across our sky. Called the ecliptic, this path passes through the familiar constellations of the zodiac. Again owing to the Earth's tilt, when the ecliptic is high during the day, it is low during the night, and vice versa.
During the summer the ecliptic is highest during the day, so the summer Sun climbs higher, and stays up longer, than the winter Sun. The full Moon, being at the opposite point on the ecliptic, is just the opposite--it climbs higher, and stays up longer, during the winter. The full Moon nearest the winter solstice, the year's longest night, is up more than 14 hours, making for a very Long Night Moon.
- Next Two Weeks: Average sunrise: 7:17 a.m.; average sunset: 5:26 p.m. (for Waco, TX)
* Tomorrow evening (Dec. 4) the crescent Moon is to the left of Venus in the southwest at dusk.
* The Moon is at 1st quarter Thursday (Dec. 8).
* The evening of Dec. 11 the Moon passes near Mars, coming within two moonwidths at 10:45 p.m.
* The Geminid meteor shower, usually one of the year's best, peaks the night of Dec.13/14, but unfortunately is washed out by the Moon all night.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) "Evening star" Venus sets nearly 3 hours after sunset and is at its brightest for the year Dec. 12. (Seen through a telescope, and maybe even binoculars, Venus now appears as a tiny crescent Moon.) Mars, high in the southeast, is fading slightly each night, but still brighter than any star. Saturn rises by 10 p.m. and is high in the southwest by morning. Jupiter is up by 5 a.m. Mercury, now rising nearly an hour and a half before sunrise, will be at its best Dec. 12 low in the southeast about 45 minutes before sunrise.
- Astro Milestones: Dec. 14 is the birthday of Danish astronomer Tycho Brahe (1546-1601).
- Stargazer Book: A Beginner's Guide to Learning the Night Sky by Paul Derrick would make a great gift for that stargazer in your life. Click here for more about my books and ordering.
November 19, 2005
Measuring Time Before Clocks and Calendars
Recently a youngster asked: How, before we sent satellites into space, did we know it took 365 days for Earth to go around the Sun? Measuring time is something we now take for granted. If we want to know the time or date, we look at a clock or calendar. But before there were clocks or calendars, our ancestors observed patterns in the movements of celestial objects, particularly the Sun, Moon and Earth.
We regularly use several measures which are arbitrary human inventions. Our 24-hour day could be divided into any number of hours, and there is no good reason for dividing hours into 60 minutes, or minutes into 60 seconds. Our 7-day week came from our ancestors naming the days for the Sun, Moon and then-known five planets.
But other familiar measures come from the natural motions of heavenly bodies. A day is based on Earth's rotation on its axis, a month derives from the Moon's orbit around Earth, and a year is the time it takes Earth to orbit the Sun.
Measuring these periods is complicated by the fact that the relationships between them aren't neat and tidy. We divide a year into 12 months, yet a lunar cycle (new Moon to new Moon) is 29.5 days, making for 12.4 "moonths" each year. Thus our month doesn't correspond to an exact lunar cycle.
The day is also messy. Not only does sunrise and sunset change daily, but the time Earth takes to orbit the Sun isn't exactly 365 days--it's 365 1/4 days. (To account for this extra 1/4 day, we insert an extra day every four years, and even this adjustment requires periodic fine tuning.)
Now back to the question of determining the number of days in a year. While the uneven relationships made calculations challenging for our ancestors, still different cultures using different methods--most based on patterns in the Sun's recurring long term movements--came up with some remarkably accurate measures.
One method involved noting where on the horizon the Sun set (or rose). The Sun sets farthest south of due west at winter solstice and farthest north at summer solstice, so counting the days from one south most setting to the next gives a good idea of the number of days in a year. Another method measured the length of the Sun's midday shadow which is longest at winter solstice and shortest at summer solstice, thus counting the days from one longest shadow to the next can indicate the length of a year.
These are but some of the many learnings used by our distant, but pretty smart, ancestors around the world, and now studied in the field of archaeoastronomy.
- Next Two Weeks: Average sunrise: 7:06 a.m.; average sunset: 5:26 p.m. (for Waco, TX)
* Late Monday evening (Nov. 21) the Moon is to the left of Saturn as they rise shortly before 11 p.m.
* The Moon is at 3rd quarter Wednesday (Nov. 23).
* The morning of Nov. 28, low in the east an hour before sunrise, the crescent Moon is below Virgo's brightest star, Spica, and above much brighter Jupiter.
* The next morning an even thinner crescent Moon is below Jupiter.
* The Moon is new Dec. 1.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Venus, the brilliant "evening star" in southwest, sets 3 hours after sunset. Mars, the brightest starlike object in the east in the evening, sets an hour before sunrise. Saturn is up by 11 p.m. and high in the south by morning. Jupiter rises at 5 a.m.
November 5, 2005
Invasion of the Martians, or Maybe the Europans?
Mars' current prominence in the night sky brings to mind H. G. Wells' famous novel, "War of the Worlds," in which Earth was invaded by hostile Martians. Writing in 1898, decades before the beginning of the Space Age, he was speaking to a ripe audience.
There was speculation that both Mars and Venus might harbor intelligent beings. Cloud-enshrouded Venus, named for the goddess of love and beauty, was seen as a Garden of Eden-like planet inhabited by gentle, peaceful beings, with blood-red Mars, named for the god of war, being home to hostile inhabitants.
We now know these ideas were entirely wrong. Venus, with its searing heat and crushing air pressure, has perhaps the most hostile environment of all the solid bodies in our solar system. Mars, with somewhat less hostile conditions, clearly harbors no intelligent life, and probably no life at all. While there are some indications that microscopic life might have lived on Mars in the past, it almost certainly wasn't Wellsian-type Martians.
What about other possible homes for life in our solar system? Mercury, nearest the Sun and almost as hot as Venus, is unlikely, as is our own barren Moon. Jupiter, Saturn, Uranus and Neptune are gas planets with no solid surface, and thus no place for life--at least as we know it--to live. Tiny Pluto, smaller than our Moon, is so far from the Sun that little heat, light or other life-sustaining solar energy even reach it.
So what's left? Some scientists think Europa, Jupiter's third largest moon, is a good candidate. So does The Planetary Society which is launching its "Explore Europa" campaign. According to TPS, "Beneath Europa's unique frozen and cracked surface, there may exist an enormous ocean of water--liquid water. And where there's liquid water, life might exist--life very different from what we're used to here on Earth--but forms of life that thrive in environments that seem to us to be impossible." Find out more about TPS and its international advocacy effort at planetary.org.
- Next Two Weeks: Average sunrise: 6:54 a.m.; average sunset: 5:31 p.m. (for Waco, TX)
* This evening (Nov. 5) the crescent Moon is to the left of Venus low in the southwest at dusk.
* Monday (Nov. 7) Mars, on the opposite side of Earth from the Sun (called opposition), is at its brightest for the next several years.
* The Moon is at 1st quarter Tuesday (Nov. 8).
* The evening of Nov. 14 the Moon and Mars travel across the sky together, setting at 6 a.m. the next morning.
* The November 15 full Moon is called the Frosty Moon and Beaver Moon.
* The Leonid meteor shower peaks the morning of Nov. 17 but is washed out by the Moon which is up nearly all night.
- Naked-eye Planets. (Due to Earth's west-to-east rotation, the Sun, Moon and planets rise in the east and set in the west.) Brilliant Venus dominates the southwestern sky at dusk with fainter Mercury to its lower right near the horizon. Mars rises at sunset, is up all night, and sets at sunrise. Jupiter, emerging from the morning Sun, rises an hour before sunrise. Saturn is up by midnight and high in the south by dawn.
- Astronomy Class: The Stargazer's 4-session "Learning the Night Sky" class will be held Nov. 14, 15, 21 and 22 from 7-9 p.m. The cost is $25 per person with family discounts and scholarships available. Call or email for information or to register.
October 22, 2005
Here Comes Mars -- Really This Time
Mars is back, big and bright, but contrary to some reports it's not closer than it's been in recorded history, and it won't look as big as the full Moon (unless seen in a telescope). Yet it's still impressive.
Rising in the east soon after sunset Mars' almost rivals brilliant Venus which is setting in the west. From now through mid November Mars will be at its largest and brightest for this go-around, making it brighter than any star and easy to identify.
Earth being the third planet from the Sun and Mars the fourth, Earth races around the Sun faster than Mars, traveling 66,700 mph compared to Mars' 53,900 mph. About every 26 months Earth passes between Mars and the Sun, bringing the two planets nearest each other. If their orbits were circular they would pass at the same distance each time, but since their orbits are elliptical they pass sometimes nearer, sometimes further from each other.
The average distance between their orbits is 48.5 million miles. This time they will pass within 43 million miles--closer than average, but not as near as August 2003 when they passed within 35 million miles.
Owing to their elliptical orbits Mars will appear largest Oct. 27 then brightest Nov. 7, yet it won't look noticeably different between the two dates. The planets pass closest Oct. 29 when Mars will appear 20 arc seconds in diameter. That's 1/90 the diameter of the full Moon, so seen in a telescope at 90-power, Mars will look as big as the Moon seen with naked eyes.
Then Nov. 7 Mars will be exactly on the opposite side of Earth from the Sun, called opposition, and will shine at magnitude -2.3, nearly as bright as Jupiter ever gets.
As Mars dominates the evening sky the next several weeks, try to view it through a telescope if you can, but even naked eyes will find it dazzling.
- Next Two Weeks: Average sunrise: 7:42 a.m.; average sunset: 6:41 p.m. (for Waco, TX)
* Monday (Oct. 24) the Moon is at 3rd quarter.
* Tuesday morning (Oct. 25) the Moon is above Saturn in the east.
* Oct. 31 is Halloween, a cross-quarter day celebrating the middle of fall.
* The Moon is new Nov. 1.
* The evening of Nov. 3 Mercury and Venus, both at their farthest above the setting Sun (called greatest elongation), are joined by a thin crescent Moon just below Mercury and the star, Antares, to their upper left. Begin looking low in the southwest 30 minutes after sunset, preferably with binoculars.
- Naked-eye Planets. (Due to Earth's west-to-east rotation, the Sun, Moon and planets rise in the east and set in the west.) Venus and Mercury are in the west at dusk, Mars rises soon after sunset, Jupiter is hiding in the Sun, and Saturn, up before 2 a.m., is high in the east in the morning.
- Astronomy Class: The Stargazer's four-session "Learning the Night Sky" class will be held Nov. 14, 15, 21 and 22 from 7-9 p.m. The cost is $25 per person with family discounts and scholarships available. Call or email for information or to register.
- Time Change: Next Saturday night (Oct. 29) before retiring, set your clocks back 1 hour ("fall back") to Standard Time.
- Astro Milestones: Oct. 29 is the 349th anniversary of the birth of Edmund Halley (1656-1742), English astronomer of Halley's Comet fame.
October 8, 2005
Mars As Big As the Full Moon?
A recent report circulating on the Internet claimed that Aug. 27 Mars was to have come closer to Earth than its been in thousands of years. The report was old news pertaining to Mars' 2003 visit. The red planet is making another close visit, coming closest Oct. 29, but more on that next time.
The report also stated that Mars would look as big as a full Moon. Now wouldn't that be a sight? Yet read carefully it is accurate. It is true that Mars, when viewed through a telescope, can appear as large as a full Moon viewed with naked eyes.
Telescopes (and binoculars) magnify things, making them look nearer and larger, and usually enabling us to see more features and details. That's why my birder wife often has a pair of binoculars around her neck--so those lovely birds will look nearer and can be more easily identified and enjoyed.
Oct. 29 Mars and Earth will pass within 43 million miles. The Moon, being 239,000 miles away, is 180 times closer than Mars will be. Thus magnifying Mars 180 times will make it appear as near as the Moon. And since Mars is twice the diameter of the Moon we only have to magnify it 90 times to make it appear the same size as the Moon seen without magnification.
But apparent size isn't the whole story. Even when a telescope makes Mars look as large as a naked-eye full Moon, the image won't be as clear as that of the Moon. Increasing a telescope's power generally reduces resolution (image sharpness) so that as the object grows larger, it becomes fuzzier.
Perhaps you've seen small telescopes advertised as magnifying 500-power (500X) or more. While misleading, this is technically not false advertising. A telescope's power is changed by changing the eyepiece, thus most come with more than one eyepiece. The stronger the eyepiece, the more the magnification. With a strong enough eyepiece even a 2-inch telescope can magnify 500X, but the image will be so blurry that it will be virtually useless.
There's a rule of thumb for determining a telescope's maximum useful power: multiply its diameter (in inches) by 50. Thus a 2-inch telescope, under good viewing conditions, can produce satisfactory images up to about 100X. Increasing the power beyond that seriously deteriorates image quality.
Next time, more on Mars' upcoming close approach.
- Next Two Weeks: Average sunrise: 7:32 a.m.; average sunset: 6:57 p.m. (for Waco, TX)
* The Moon is at 1st quarter Monday, Oct. 10.
* The evening of Oct. 16 Venus passes above Scorpius' brightest star, Antares.
* The Oct. 17 full Moon, called the Hunter's Moon (being the full Moon following the Harvest Moon), produces a barely noticeable partial eclipse of the Moon at dawn.
* Oct. 18 the Moon rises soon after sunset followed 1/2 hour later by Mars, then the two travel across the sky together all night.
* The next night (Oct. 19) the Moon is below Mars and near the Pleiades star cluster, although the Moon's glare will make it difficult seeing the cluster without binoculars.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Mercury sets less than an hour after the Sun while Venus, the "evening star," is low in the west for 2 hours after sunset. Mars rises as Venus sets, moves across the sky all night, and is high in the west at dawn. Saturn, up by 2 a.m., is in the east in the morning.
September 24, 2005
Science and Religion In Conflict?
Attempts to have theories of creationism and intelligent design included in public school science texts and curricula again raise questions about a seeming conflict between science and religion. Astronomical history suggests that forays of religion into science might not be wise.
To deal with ideas of truth, goodness and beauty, we have invented science, religion and art. While they can interact, they are separate with each using different rules for knowing.
Within the realm of truth, the role of science is to build a body of reliable knowledge to enable us to describe, understand, predict and exercise control over our world. Using rigorous rules of evidence, the scientific method is ruthless--no idea is sacrosanct or beyond scrutiny. Theories are modified or discarded when they can't stand up to empirical testing.
It has served us well as all the comforts of every-day life are products of science. But while science can tell us what is, it can't tell us what should be. Science can enlighten us about consequences, but can't tell us what is desirable. It can explain a colorful sunset, but can't speak to its beauty.
Within the realm of goodness, the role of religion (some prefer philosophy) is to help us deal with values--questions of good and evil, purpose and meaning. While science contributes to physical comfort, it is religion that can provide emotional (spiritual) fulfillment. And while science studies consequences of values-driven behaviors, it can't judge the values themselves. Science enables us to grow food and build bombs, but only values tell us who should get food and who should get bombed.
Creation stories, deriving from ancient religious teachings, provided comfort for our prescientific ancestors. The writings from which these ideas came were intended to serve religious, not scientific, ends. Bringing religious ideas and writings into the science classroom makes them fair game for rigorous, even brutal, scientific scrutiny. Did we not learn the folly of such when the 16th and 17th century church persecuted Copernicus, Galileo and others for teaching that Earth is not the center of the cosmos, only to have to recant its error in the 20th century?
The great genius Albert Einstein saw no inherent conflict between science and religion when he said, "Science without religion is lame, religion without science is blind." Operating in different realms, each can enlighten the other.
Stargazing touches each realm. We can contribute to science, find personal and spiritual meaning and adore the beauty of the cosmos--all in one evening. We need not even agree on what is beautiful or meaningful to share camaraderie with each other.
- Next Two Weeks: Average sunrise: 7:22 a.m.; average sunset: 7:14 p.m. (for Waco, TX)
* This evening Venus is to the lower left of Alpha Librae, a double star with a fainter companion visible in binoculars.
* Tomorrow (Sept. 25) the Moon is at 3rd quarter.
* Wed. morning (Sept. 28) the Moon is to the lower left of Saturn.
* The Moon is new Oct. 3.
* The crescent Moon is below Venus in the southwest after dusk Oct. 6.
* The next evening (Oct. 7) it is nearer the star Antares low in the west.
- Naked-eye Planets. Venus, the brilliant "evening star" low in the west, sets 2 hours after the Sun as Jupiter is sinking into the setting Sun. Mars, getting closer and brighter, rises after 9 p.m. and is high in the southwest by morning. Rising 4 hours before the Sun, Saturn is low in the east before dawn.
September 10, 2005
Saturn Stirs Up a Beehive
The planet Saturn stirs up a swarm of celestial bees this month as it passes a star cluster called the Beehive. But you've got to be an early bird to see this predawn show.
Rising in the east three hours before the Sun, Saturn is best seen an hour to an hour and a half before sunrise. You'll notice three bright starlike objects 20-25 degrees above the eastern horizon and aligned 20-25 degrees apart. (The width of your fist held at arm's length is 10 degrees.) Saturn, to the left, is slightly lower than the other two which are stars--Procyon in the middle and Sirius, the night sky's brightest star, to the right.
The Beehive, an open star cluster in the constellation Cancer the Crab, also goes by other names: M44, NGC 2632, Praesepe, and the Manger. To naked eyes and under reasonably dark skies it looks like a faint, easily-missed fuzzball about the size of a full Moon. However in binoculars (or a telescope at low power) its dazzling swarm of some 200 individual stars pops into view.
As stars go, these are young--a mere 400 million years old--compared to Saturn (and the rest of our solar system) at nearly 5 billion years. At a distance of 515 light years, the Beehive is a nearby cluster, yet vastly further than Saturn which is 900 million miles away.
Passing to the right of the Beehive, Saturn closes to within a mere 1.2 degrees of the cluster's center Sept. 14--the width of your finger held at arm's length. And since Saturn moves slowly against the background stars it will remain within 2 degrees the rest of the month.
While you're out early, you can also get a preview of what's coming in late fall and early winter. As Earth journeys around the Sun, each season presents a different set of constellations. With fall approaching we are starting to see the fall night sky--those constellations prominent in the evening hours of fall (since most stargazing occurs in the evening).
But as Earth rotates on its axis daily, the constellations slowly move across the night sky so that by morning the sky has changed about a season's worth of constellations. Thus morning viewing gives a preview of the next season's evening night sky. Above Saturn and the Beehive, the winter sky is rising in the east, displaying such winter delights as the Great Winter Arc, Taurus the Bull, the Pleiades cluster and Orion the Hunter. And notice bright Mars high in the south, preparing for its late October drama.
Next Two Weeks. Average sunrise: 7:14 a.m.; average sunset: 7:32 p.m. (for Waco, TX)
* This evening (Sept. 10) the Moon is to the left of the star Antares.
* Tomorrow (Sept. 11) the Moon is at 1st quarter.
* The Sept. 17 full Moon is called Fruit Moon, and as the full Moon nearest the fall equinox this year, it is also the Harvest Moon.
* Sept. 21 the Moon is to the upper left of Mars as they rise in the east just after 10 p.m.
* Fall begins Sept. 22 with the autumnal equinox when night and day are of equal length.
Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) "Evening star" Venus and Jupiter (to the lower right) still grace the evening sky low in the west at dusk. In the morning Mars, now rising before 11 p.m., is the brightest object high in the south while Saturn is low in the east.
Astro Milestones. Sept. 23 is the 159th anniversary of the 1846 discovery of Neptune from the Berlin Observatory.
August 27, 2005
Venus and Jupiter Together at Dusk
Hopefully you've been noticing the planets Venus and Jupiter low in the west at dusk. With brilliant Venus nearer the horizon and bright Jupiter to the upper left, they have been approaching each other for some time. When they rendezvous Sept. 1 they will be only about two moonwidths apart--the width of your index finger held at arm's length.
The planets' close approach--called a conjunction--gives some insights into one of the more prominent religions of the ancient Greek and Rome Empires. Jupiter (aka Zeus) was the king of the gods, and Venus (aka Aphrodite) the goddess of love and beauty. According to many stories of the religion, both had active love lives--with each other, and with many others.
Given the continuous movements of the planets, and it's easy to see how these legends and myths originated. Jupiter and Venus not only pass near each other regularly, but each also frequently visits other heavenly deities--especially the fast moving Venus.
Sept. 3 the planets align with the star, Spica, with Jupiter to the right, Spica to the left, and Venus in the middle. Although it's the night sky's 15th brightest star, Spica pales in comparison to planets. Venus passes nearest Spica Sept. 5 and 6, then the crescent Moon joins the trio Sept. 6 and 7 to produce a dramatic quartet you won't want to miss.
Throughout September Jupiter sinks toward the setting Sun and leaves the evening sky in late October. Venus, however, remains the "evening star" for rest of the year, not joining Jupiter in the morning sky until Jan. 2006.
As Venus and Jupiter dazzle us in the early evening before setting soon after the Sun, the other naked-eye planets come up later. Earth's west-to-east rotation makes the Sun, Moon and planets appear to rise in the east and set in the west. So after we see Venus, Jupiter and the Sun set in the west, we'll see the three other planets rise in the east.
Mars, the god of war and one of Jupiter's many sons, makes his appearance before midnight. By dawn he is the brightest object high in the south. Earth and Mars are coming nearer each other in their orbits around the Sun, making Mars come up slightly earlier each night and also gradually grow brighter and larger. It will be at its best--brightest, largest and in the sky all night--the last week of October and first week of November.
Saturn, Jupiter's father, rises two hours before the Sun and an hour before Mercury, the messenger god and another of Jupiter's sons. At dawn Mercury is near the eastern horizon with Saturn a little higher up. Saturn spends September near Cancer's Beehive star cluster, the two coming closest Sept. 14. They are already a lovely sight in the same binocular field of view.
- Next Two Weeks: Average sunrise: 7:05 a.m.; average sunset: 7:50 p.m. (for Waco, TX)
* Wed. (Aug. 31) a crescent Moon is above Saturn near the eastern horizon just before dawn with Mercury well below them near the horizon.
* The next morning (Sep. 1) an even thinner Moon is between them.
* The Moon is new Sept. 3.
* The evening of Sept. 8 the crescent Moon is to the lower left of the binocular double star, Alpha Librae, with all in same binocular field of view.
- Public Star Party: The 7th Annual Lake Whitney State Park Summer Star Party is today (Aug. 27) beginning at 4 p.m. with indoor programs and outdoor evening viewing. The event is free except for the nominal park entry fee.
- Minor Astro Milestone: Today the Stargazer becomes an official "old geezer" -- I turn 65 and am now on Medicare! Geez!
August 13, 2005
The Fox's Swan Song
High overhead in the early evenings of summer, three bright stars--Vega, Altair and Deneb--form the Milky Way Triangle (also known as the Summer Triangle.) Vega is in the constellation Lyra the Musical Lyre (Harp), Altair in Aquila the Eagle, and Deneb in Cygnus the Swan. These constellations, along with the fainter Vulpecula the Fox and Sagitta the Arrow, tell the short but instructive story of the fox's swan song.
Known for intelligence and cunning, foxes are predatory mammals which hunt by stealth. Being rather small, they are usually content with a diet of small animals and fruits. But not so the greedy and overly-ambitious Vulpecula who spots nearby Cygnus, and decides to go for the big bird.
He's feeling pretty lucky, having dodged Sagitta sailing beneath his belly. However, his grandiose plans have made him uncharacteristically careless. He fails to notice Aquila bearing down on him, about to turn him from predator to prey. With Vulpecula's impending demise, we hear the somber music of Lyra playing the fox's swan song.
OK, so the story's a bit hokey, but it helps one remember the characters, and thus the constellations, of the night sky's Milky Way Triangle region.
Finding the triangle is not difficult. Facing east, Vega is the bright star high overhead while Altair is 35 degrees to Vega's the lower right and Deneb 25 degrees to Vega's lower left. (The width of your fist held at arm's length is 10 degrees.)
Seeing the constellations is more difficult without help. Lyra is distinctive but small. Large Cygnus is flying left-to-right along the Milky Way with its central part forming the "northern cross." Aquila is flying right-to-left just below the Milky Way. Small Vulpecula is between the two birds with even smaller Sagitta just beneath it. Since foxes survive by stealth and arrows are swift, it's fitting that both are difficult-to-see faint-star constellations.
- Next Two Weeks:Average sunrise: 6:57 a.m.; average sunset: 8:06 p.m. (for Waco, TX)
* Friday's August 19 full Moon is called the Green Corn Moon, Grain Moon and Fruit Moon. (As this full Moon nearly coincides with perigee, when the Moon is nearest Earth, the Moon will appear slightly larger than average.)
* The morning of Aug. 25 the Moon is above Mars.
* The next morning (Aug. 26) the 3rd quarter Moon is near Taurus' Pleiades star cluster.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Brilliant Venus is approaching bright Jupiter to the upper left low in the west at dusk, leading up to their Sept. 1 conjunction. Mars, rising at midnight, is high in the south at dawn. Saturn and lower Mercury are seen near the eastern horizon an hour before sunrise with the Beehive cluster between them.
- Astronomy Class. The Stargazer's four-session "Learning the Night Sky of Summer" class will be held Aug. 22-25 from 8-10 p.m. The cost is $25 per person with family discounts and scholarships available. Call or email for information or to register.
- Public Star Party. The 7th Annual Lake Whitney State Park Summer Star Party will be Aug. 27 beginning at 4 p.m. with indoor programs and outdoor evening viewing. The event is free except for the nominal park entry fee.
July 30, 2005
Time for the Annual Perseid Meteor Shower
The annual Perseid meteor shower, usually one of the year's best, is just around the corner, and the Moon won't be much of a problem this year. The shower's actually peak is predicted for the afternoon of Aug. 12, but, since we don't see many meteors during daylight hours, we can expect two nights of increased activity -- Thursday, Aug. 11 and Friday, Aug. 12.
When viewing meteor showers, location and timing are more important than equipment. For casual observing only one piece of equipment is recommended--a reclining lawn chair.
Regarding location, light pollution is the key factor. The farther one is from urban and other interfering lights, the more meteors one will see, just as more stars will be seen. But those who must view from within a city shouldn't despair as brighter meteors can still be seen, to the same extent as can brighter stars and planets. And more meteors will be seen from an open area unobscured by trees or buildings.
Meteor viewing is usually at its best during the inconvenient hours from midnight to dawn. And this is especially true for the Perseids as Perseus, the constellation from which the meteors appear to come, rises after midnight. And this year, the Moon produces "natural" light pollution until it sets shortly before midnight Aug. 11 and just after midnight the next night. So you'll need to stay up late (or get up early) for the best show.
People often ask what direction they should look for meteors. Although Perseus rises in the northeast, meteors are likely to be seen in all parts of the sky. So the greatest number of meteors will probably be seen in the direction with the least light pollution which for most locations is overhead.
Although the hours after midnight are not the best for parties, viewing with friends can greatly enhance the experience. Since at its peak the shower is likely to produce no more than a meteor per minute, friends can help pass the time. As you visit and enjoy refreshments, keep looking upward, slowly panning the sky.
- Next Two Weeks: Average sunrise: 6:48 a.m.; average sunset: 8:20 p.m. (for Waco, TX)
* Monday (Aug. 1) is Lammas, the cross-quarter day celebrating the middle of summer.
* The Moon is new Thursday (Aug. 4).
* Aug. 7 the crescent Moon is below Venus low in the west at dusk, the next evening between Venus and Jupiter, and Aug. 9 just below Jupiter.
* The Moon is one moonwidth above Virgo's brightest star, Spica, the evening of Aug. 10.
* The Moon is at 1st quarter Aug. 12.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Venus is the brilliant "evening star" low in the west at dusk with Jupiter the next brightest starlike object higher in the southwest. Mars rises after midnight and is high in the southeast by morning.
- Stargazing Class. The Stargazer's 4-session "Learning the Night Sky of Summer" class will be held Aug. 22-25 from 8-10 p.m. The cost is $25 per person with family discounts and scholarships available. Call or email for information or to register.
July 16, 2005
Two Ways of Looking at Constellations
For those with imagination, the night sky is full of strange and exotic people, animals and other objects--88 things which collectively we call constellations. But there are two ways stargazers look at constellations.
Typically we think of patterns formed in the night sky by groups of stars. Orion, for example, is a widely recognized pattern in the winter sky. Using imagination to fill in the details, it's not too hard to "see" a giant hunter with two stars at his shoulders, two more at his knees, three forming his belt, and three more making his sword hanging from his belt.
As long as we know, humans have seen imaginary figures in the night sky. Not surprisingly, people in different lands saw different things. Where Europeans saw a swan, perhaps Africans saw a zebra, and South Americans a giant turtle.
The constellations we retain to this day are products of the culture and experiences of our European and Middle Eastern ancestors. Most come from antiquity--the ancient Greeks, Babylonians and probably earlier people. These civilizations lived in the Northern Hemisphere, so they created constellations in the part of the sky they could see. "Modern" constellation--mostly those seen from the Southern Hemisphere--were created after Europeans began exploring the world and seeing parts of the night sky they'd never before seen.
Officially, astronomers view constellations differently, seeing them as areas rather than patterns. Each constellation is an area of sky defined by precisely drawn boundaries. If the sky was the continental U.S., each constellation would be like a state, and each star like a city. Just as each place and city within the U.S. is within some state (ignoring Washington, DC), each place and star in the sky is within some constellation.
The 88 constellations officially recognized by the International Astronomical Union follow the historical constellations, so even astronomers with imagination can see 14 people, 43 animals, and 31 inanimate objects. So even on the darkest of nights, stargazers are never alone under the stars.
- Next Two Weeks: Average sunrise: 6:39 a.m.; average sunset: 8:31 p.m. (for Waco, TX)
* Tomorrow evening (July 17) the Moon occults (passes in front of) Scorpius' brightest star, Antares, around 11:30 p.m. This will be a rare grazing occultation from parts of Central Texas.
* Thursday's (July 21) full Moon of July is called the Thunder Moon, Hay Moon and Grain Moon. This full Moon occurs when the Moon is at perigee--nearest Earth in its elliptical orbit--thus it will appear slightly larger than the average full Moon.
* Early Friday evening (July 22) Venus passes just above Leo's brightest star, Regulus, low in the west soon after dark. Binoculars might help spot the star.
* The morning of July 27 the 3rd quarter Moon is above Mars.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Venus, the "evening star," appears low in the west and sets at 10 p.m. Fainter Mercury, the brightest object below Venus, sets at 9:45, and within 2 weeks is lost in the setting Sun. Jupiter, the brightest starlike object higher in the southwest, sets after midnight. Morning: Rising at 1 a.m., Mars is the brightest object in the southeast by morning.
- Astro Milestones. July 20 is the 36th anniversary of the 1969 lunar landing when U.S. astronauts Neal Armstrong and Buzz Aldrin became the first humans to land and walk on the moon. Will it happen again in our lifetime?
July 2, 2005
Is Mars Really Coming Close or Not?
Perhaps you've seen it on the internet or heard it from a friend: On August 27 Mars will come closer to Earth, and appear larger and brighter, than it's been in umpteen-thousand years. Does that sound familiar? It should--it happened two years ago. It's history, not news, and a reminder that we should view what we read on the internet (or anywhere else) with a critical eye.
Even so, it's not totally off base. Mars is coming around for another near pass--something it does every 2-plus years. In the fall we will pass between the red planet and the Sun, bringing Earth and Mars close once again.
On average Mars orbits 141 million miles from the Sun while Earth orbits at 93 million miles, thus on average they are 48 million miles apart when they pass. But their orbits, like those of all planets, are elliptical rather than circular.
Earth's orbit brings it nearest the Sun (called perihelion) each January at a distance of 91 million miles, and farthest from the Sun (called aphelion) each July at 95 million miles. Mars' orbit is even more elliptical with perihelion at 128 million miles and aphelion at 155 million miles.
If the planets happen to pass when Earth is at perihelion and Mars is at aphelion, they come no closer than 64 million miles apart. But with Earth at aphelion and Mars at perihelion, they pass within 33 million miles. The latter was nearly the case in 2003 when Mars passed less than 35 million miles from us, and did appear larger and brighter than we've ever seen it. In late October it will come within 43 million miles--nearer than its average pass--and again appear larger and brighter than usual. It won't match its 2003 show, but will still be worth viewing.
- Deep Impact Reminder: Deep Impact crashes into Comet Tempel 1 at 12:52 a.m. July 4. See my website for more details.
- Next Two Weeks: Average sunrise: 6:31 a.m.; average sunset: 8:36 p.m. (for Waco, TX)
* The midpoint of the year 2005 occurred this morning (July 2) at 1 a.m.
* Tomorrow morning (July 3) a thin crescent Moon is to the lower left of the Pleiades star cluster low in the east.
* Tomorrow evening (July 3) at the end of dusk, using binoculars, look for brilliant "evening star" Venus and Mercury (to Venus' left) just below the Beehive star cluster low in the west.
* The next evening (July 4) Venus passes through the cluster as Mercury passes to its left.
* Tuesday (July 5) Earth reaches aphelion, its farthest point from the Sun for the year.
* The Moon is new Wednesday (July 6).
* Early Friday evening (July 8) a thin crescent Moon is above Venus with Mercury to Venus' lower left low in the west at dusk.
* The next evening (July 9) the Moon is to the right of Leo's brightest star, Regulus.
* The evening of July 12 the Moon is to the lower right of Jupiter.
* The next evening (July 13) it is between Jupiter and Virgo's brightest star, Spica.
* July 14 the Moon, at 1st quarter, is to Spica's upper left.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Saturn is disappearing into the setting Sun, while Venus, low in west at dusk, is gradually climbing higher each evening. Fainter Mercury, to Venus' left, will sink into the setting Sun by month's end. Jupiter, still the brightest object in the southwest, sets at midnight. Morning: Mars, rising at 1:30 a.m., is the brightest starlike object high in the southeast before dawn.
- Stargazer's Books. Don't forget about my books: (A Beginner's Guide to) Learning the Night Sky ($15) and Stargazer's Life List ($20), or both for $30. Prices include sales tax, but add $2 for mailing one book, $3 for both. To learn more about these books, their contents, and how to order, click HERE.
- Library? / Bookstore? If your local public library would like to have a copy of Learning the Night Sky, email the name and address to me and I'll send them a complimentary copy. If you have a local bookstore you think might be interested in carrying LNS (wholesale or consignment basis), send me their information, or tell them about me. (Thanks to those who responded to this item last time.)
- Stargazer in Your Paper? Stargazer appears in some 35 Texas newspapers (and now one Arkansas paper!). If you think your local paper might be interested in the column, let me know, or let them know about Stargazer. There is no charge for smaller papers; my website also has information for interested papers.
June 18, 2005
Planetary Meeting and Seeing Comet Tempel
Remember double-feature movies? Well the night sky is about to give us a double-feature show, one by Mother Nature, another by NASA. Next week's meeting of three planets is followed by the July Fourth crash of the Deep Impact probe into Comet Tempel 1.
Venus, Saturn and Mercury, now visible low in the west at dusk, are closing in on each other. By June 25 they will be tightly grouped with Venus and Mercury separated by 1/2 degree (the width of a full Moon) and Saturn 1 1/2 degrees to their lower left.
Look for them 10 degrees (the width of your fist held at arm's length) above the western horizon 45 minutes after sunset. Venus is the brightest, and while the other two are visible to naked eyes, binoculars will enhance one's view.
But keep watching a few more evenings. As Saturn sinks toward the setting Sun, Mercury and Venus pass breathtakingly close to each other. June 26 they are 1/6 degree apart, and the next evening they come closest at 1/8 degree--a sight not to miss.
NASA's show won't be as easy to see. The spacecraft Deep Impact, launched Jan. 12, is composed of a flyby and an impactor. Traveling 23,00 mph the 820-pound impactor will crash into Comet Tempel 1 about 1 a.m. July 4, blasting a crater in the comet's nucleus. By studying the crater and the ejected debris, scientists hope to learn more about comets and star-formation.
While hundreds of astronomers will be observing the event, predicting what amateurs and the general public might see is difficult. When we see a comet, we're not actually seeing the comet's several-mile-wide nucleus. Rather we see cometary dust and gasses released when the comet's outer layer is melted away by heat from the Sun, and illuminated by sunlight.
Comet Tempel 1 never comes nearer the Sun than does Mars, so little material is melted away. As a result it is always faint, never visible with naked eyes or even with ordinary binoculars. But dust and gasses released by the impact will likely cause the comet to brighten. How much and for how long is anyone's guess, but it will probably be visible in binoculars for several days. And it might even be barely seen by naked eyes under dark skies.
We have help finding the comet as it is near bright Jupiter and even nearer the star Spica. At the time of impact Tempel 1 is just above Spica which is to the upper left of Jupiter near the western horizon.
For the next few weeks the comet is up from dark until after midnight. In the early evening Jupiter is the brightest object in the southwest with Spica to its left and Tempel 1 to Spica's upper left. Through July 9 the comet is less than 5 degrees (within the field of view of most binoculars) from Spica.
For more information see my website at www.stargazerpaul.com.
- Next Two Weeks: Average sunrise: 6:25 a.m.; average sunset: 8:37 p.m. (for Waco, TX)
* Tuesday (June 21) is the summer solstice, the first day of summer and year's longest day in the Northern Hemisphere.
* Tuesday is also the full Moon of June, called Strawberry Moon, Flower Moon and Rose Moon.
* The Moon is at 3rd quarter June 28.
* The morning of June 29 the Moon is to the lower left of Mars low in the east.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Mercury, Venus and Saturn are seen low in the west at dusk. Jupiter, high in the southwest, sets at 2 a.m. Morning: Mars up at 2 a.m. is high in the southeast before dawn.
- Stargazer's Books. Don't forget about my books: (A Beginner's Guide to) Learning the Night Sky ($15) and Stargazer's Life List ($20), or both for $30. Prices include sales tax, but add $2 for mailing one book, $3 for both. To learn more about these books, their contents, and how to order, click HERE.
- Additional Note. If your local public library would like to have a copy of Learning the Night Sky, email the name and address to me and I'll send them a complimentary copy. If you have a local bookstore you think might be interested in carrying LNS (wholesale or consignment basis), send me their information, or tell them about me. Thanks.
June 4, 2005
Mission: Deep Impact
If all goes as planned, this year's July 4th will be celebrated like never before when NASA's Deep Impact mission crashes an 820-pound projectile into Comet Tempel 1 at 1 a.m. July 4. While the event won't appear as spectacular as your local fireworks, that won't detract from the excitement it holds for astronomers.
Comet Tempel 1, a potato-shaped object a few miles in diameter, orbits the Sun every 5.5 years in a highly elliptical orbit. Its farthest point from the Sun is nearly as far out as Jupiter, and its nearest point is just beyond the orbit of Mars, where it will be during the July 4 impact.
Comets, like planets, moons and asteroids, are byproducts of the formation of our Sun 4.5 billion years ago. But unlike planets and moons, comets likely contain pristine material unchanged by geologic processes, the study of which may help scientists learn more about star-formation.
Deep Impact, consisting of an "impactor" attached to a "flyby" spacecraft, was launched January 12, 2005. Twenty-four hours before impact, the impactor will separate and head for the comet. Both components have cameras and other instruments.
Traveling 23,000 mph relative to the speed of the comet, the impactor will return images up to the instant of impact. The flyby will return images and other data before, during and after impact. Indeed, what happens after impact is of most interest.
Scientists expect a crater to be blasted out of the comet, the size and nature of which will be determined by, and thus will reveal much about, the nature of the comet's composition. Analysis of the crater and ejected materials can help answer questions like: how dense are comets? are they tightly or loosely compacted? is the inner material the same as the outer?
In addition to the mission's scientific value, it should yield some very practical information. Comets have crashed into Earth before, and will do so again. While no one is predicting one anytime soon, if we were to discover a new comet headed our way, it would be critical to know all we can about them. Seeing what happens to Comet Tempel 1 can help us know whether a threatening comet could be broken up or its course altered, or if an impact with Earth is unavoidable, how we could best prepare for it.
Next time we'll discuss what, if anything, amateur astronomers and the general public might expect to see from Earth.
- Next Two Weeks: Average sunrise: 6:23 a.m.; average sunset: 8:33 p.m. (for Waco, TX)
* This period features the Moon which is new Monday (June 6).
* Early Wednesday evening (June 8) a thin crescent Moon is above Venus low in the west at dusk, and Thursday evening (June 9) to the upper right of Saturn.
* By Friday evening (June 10) the larger crescent is to the upper right of Cancer's Beehive star cluster, and by June 12, to the upper right of Leo's brightest star, Regulus.
* The Moon is at 1st quarter June 14.
* The next evening (June 15) it is near Jupiter high in the southwest, the two closing to within two moonwidths when they set after midnight.
* June 16 the Moon is to the upper right of Virgo's brightest star, Spica, high in the south.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: "Evening star" Venus is low in the north northwest at dusk with Saturn a little higher in the west. Jupiter is the brightest object high in the south. Morning: Mars is bright reddish object in the southeast.
- Lake Whitney Musical Star Party. The Texas Stars & Guitars Fest is today (June 4) at Lake Whitney State Park with live acoustic music beginning at noon, solar viewing in the afternoon and a sky tour and telescope viewing after dark. The event is free except for the nominal park entry fee.
May 21, 2005
Telling Planets from Stars
This is a great time to see Jupiter and Saturn as both are now prominent in the evening sky. But as many at public star parties ask, how can one tell the planets from the stars since they all look like tiny points of light?
Unless one is pretty familiar with the night sky it's not easy, and just like the Moon isn't always out (above the horizon), sometimes none of the planets are out. But when they are, here are some pointers to help find them.
Only five planets--Mercury, Venus, Mars, Jupiter and Saturn--are visible to naked eyes, and all are usually brighter than most stars. Perhaps you've heard the saying, "stars twinkle, planets don't." Except for those nights when Earth's atmosphere (which produces the twinkling) is steady and the twinkling of stars isn't real apparent, the saying is generally true. So look for brighter objects that don't seem to twinkle.
The planets orbit the Sun on nearly the same plane, so they all closely follow the Sun's path across our sky, called the ecliptic. Since the Moon also orbits Earth on this plane, it too travels along the ecliptic.
Just like the Sun, the planets (and Moon) rise in the east, travel across the sky, and set in the west. So when looking for planets, face south and stretch out your arms slightly more than 180 degrees. Any visible planets will be in front of your arms--never be behind you nor straight overhead. Any that are above the horizon will be somewhere along the great ecliptic arc which begins near the eastern horizon, passes about half way up in the south, and ends near the western horizon.
When not hidden in the Sun's glare, Venus and Mercury, the inner planets which orbit near the Sun, are only seen in the west after sunset or in the east before sunrise. The outer planets can rise or set, and thus be seen, any time during the night.
This column tells which naked-eye planets are currently visible in the evening and morning, and where to look for them. More precise information is available in monthly magazines like Sky & Telescope and Astronomy, and from websites like skymaps.com, skyandtelescope.com and astronomy.com.
- Next Two Weeks: Average sunrise: 6:26 a.m.; average sunset: 8:26 p.m. (for Waco, TX)
* The May 23 full Moon is called the Planting Moon, Milk Moon and Flower Moon.
* Although the Moon's glare will make it difficult to see, the morning of May 24 the Moon occults (passes in front of) Scorpius' brightest star Antares. The star disappears from the Moon's left side about 2:44 a.m. and reappears on the right side about 4:02 a.m. (Exact times depend upon one's viewing location.) At least binoculars will be needed.
* The Moon is at 3rd quarter May 30.
* The Moon passes just below Mars the morning of May 31.
- Naked-eye Planets: Evening: Venus is emerging as the "evening star" but still sets during twilight an hour after the Sun. Saturn, a little higher in the west, sets at midnight while brilliant Jupiter, high in the south, sets at 4 a.m. Morning: Mars is the brightest object in the southeast while Mercury is sinking into the morning Sun.
- Lake Whitney Event: The Texas Stars & Guitars Fest will be June 4 at Lake Whitney State Park with live acoustic music beginning at noon. There will be telescope viewing of the Sun during the day and a sky tour and telescope viewing after dark. The event is free except for the nominal park entry fee.
May 9, 2005
Using Mars to Find Uranus
Throughout history our ancestors have been aware of the five brightest planets--Mercury, Venus, Mars, Jupiter and Saturn--although they didn't know what they were. They looked like stars, yet the "fixed stars" stayed in the same place relative to each other while these five objects moved among them. So they called them planets, which means "wanderers," not even realizing that Earth is also a planet.
When in 1609 Italian astronomer Galileo first used the newly invented telescope as an astronomical instrument, our knowledge of the cosmos began to increase "astronomically." The combined efforts of Copernicus, Tycho Brahe, Galileo and Johannes Kepler, working mostly independently of each other, helped us understand that these planets orbit our Sun, and that Earth is also a planet. But they still only knew of the five, plus Earth.
It wasn't until 1781 that the musician-astronomer William Herschel, from his home observatory in Bath, England, discovered the planet Uranus. Then Neptune was discovered in 1846, followed by Pluto in 1930. These three planets are so distant and faint it's no wonder they weren't discovered until recent times. Since none are visible to the naked eye, most have never seen them. (Actually Uranus is barely visible under the right conditions, but generally it's not considered a naked-eye object.)
If you've never seen Uranus, and would like to, you'll have a great opportunity for several mornings beginning around May 12 when Mars, which is easy to see, passes near the elusive Uranus. You'll need binoculars and reasonably dark skies.
Reddish Mars, blue-green Uranus and a reddish star form a trio, with Mars the brightest and Uranus the faintest of the three. Uranus moves so slowly that it and the star will seem to stay the same distance from each other, but swifter Mars moves noticeably from one morning to the next.
An hour or two before dawn Mars is the brightest object rising in the southeast. The morning of May 12 the three are aligned with Mars to the right and Uranus in the middle--all within the same binocular field of view. By May 16 they form a small triangle with Mars at the bottom.
- Next Two Weeks: Average sunrise: 6:32 a.m.; average sunset: 8:17 p.m. (for Waco, TX)
* The Moon is new tomorrow (May 8).
* Thur. evening (May 12) the crescent Moon is below Saturn and Gemini's brightest stars Pollux and Castor, Saturn to the left being the brightest.
* Friday the 13th (an unlucky day for the superstitious) the Moon is above Saturn and Pollux.
* The evening of May 14 the crescent Moon is above Cancer's Beehive star cluster. (The Beehive is usually seen with naked eyes, but binoculars will probably be needed due to the glare of the nearby Moon.)
* The evening of May 16 the 1st quarter Moon is to the left of Leo's brightest star, Regulus, then to the lower left of Jupiter May 19.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Venus is the "evening star" seen very low in the west shortly after sunset. Saturn, the brightest starlike object high in the west, sets about 1 a.m., while brilliant Jupiter, up nearly all night, is high in the southeast in the evening. Morning: Mars, rising after 3 a.m., is seen in the southeast. Mercury is barely visible near the eastern horizon 45 minutes before sunrise.
April 23, 2005
Spring Means Cosmic Baseball
Here we are in the middle of spring, which for many means gardening, mowing lawns, enjoying Texas' wonderful wildflowers, and baseball. For stargazers, it also means cosmic baseball. During the late spring and summer, the heart of baseball season, the night sky features its own cosmic baseball game.
As soon as the sky darkens, about an hour after sunset, face east (opposite from where the Sun went down). Look high in the northeast (upper left) for the Big Dipper. It's curved handle and a corny saying help us locate home plate, the star Arcturus. The dipper's handle "arcs to Arcturus" 30 degrees to the lower right. (The width of your fist held at arm's length is 10 degrees.) Arcturus is the very bright, slightly reddish star 35 degrees above the eastern horizon.
Now look for a bright white star, Spica, 30 degrees to Arcturus' right and 30 degrees above the horizon in the southeast. Spica is first base.
Second base is the star Denebola, 35 degrees above and slightly left of the brighter Spica. (Don't be confused by the very bright object between them. That's Jupiter which is just passing through the area this year.)
Third base is the even fainter star Cor Caroli situated 30 degrees to the lower left of Denebola, and 25 degrees above Arcturus (home plate). Cor Caroli is the brightest star nestled under the arc of the Big Dipper's handle.
Those familiar with baseball know we need two more positions to round out our infield. For shortstop we have the lovely, large Coma Berenices star cluster, best seen under darker non-urban skies. The pitcher is the star 47-Epsilon Virginis, about as bright as Cor Caroli and located near the center of the diamond. It has no common name, so I call it Charlie Brown.
Well, that's the infield of the cosmic baseball diamond, also known as the Diamond of Virgo. The outfield is composed of constellations but we'll save them for another time.
- Next Two Weeks: Average sunrise: 6:44 a.m.; average sunset: 8:08 p.m. (for Waco, TX)
* Tomorrow (Apr. 24) night's full Moon, called Grass Moon, Egg Moon, Pink Moon and Milk Moon, will feature a slight, barely noticeable penumbral (shading) lunar eclipse.
* May 1 is May Day (aka Beltane), a cross-quarter day celebrating the middle of spring, and the Moon is at 3rd quarter.
* The morning of May 2 the Moon is to the right of Mars low in the southeast, and the next morning (May 3) below Uranus (but seeing Uranus requires at least binoculars).
* This is a favorable year for the Eta Aquarid meteor shower which peaks the morning of May 5. Aquarius, from which the meteors appear to radiate, rises at 3 a.m. to a moonless sky.
* The morning of May 6 a thin crescent Moon is just to the left of Mercury near the eastern horizon shortly before dawn.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Jupiter, the brightest object in the southeast, is up nearly all night. Saturn, the brightest object high in the west, sets after midnight. Venus still sets too soon after the Sun to be seen easily. Morning: Mercury rises an hour before the Sun and is barely visible just above the eastern horizon 45 minutes before sunrise. Mars in the southeast rises 3 hours before the Sun.
April 9, 2005
The Age of Aquarius?
"When the Moon is in the 7th House, and Jupiter aligns with Mars / Then peace will guide the planets, and love with steer the stars." This wonderful "age of Aquarius" was predicted by the 1960s rock opera "Hair" in the song "Aquarius" made popular by The Fifth Dimension. The musical prediction was reportedly made in consultation with astrologers.
If astrology and the Internet are to be believed, peace and love should start sweeping over us any time now. According to an Internet report sent to me by a friend, Jupiter and Mars were aligned in a "trine" with the Moon in the 7th house on April 7. In astrology a trine is a good-omen alignment occurring when two objects are separated by 120 degrees as seen from Earth.
Being an amateur astronomer, and not an astrologer, I decided to check it out with my astronomy software. Sure enough the morning of April 7 Jupiter was in the southwest 120 degrees from Mars in the southeast. I'm not sure the Moon was right as it was in the constellation Pisces which according to my sources is the 12th house. So will peace and love have to wait a while longer?
Checking further I found that Jupiter-Mars trine alignments aren't rare, occurring about every 13 months. And the Moon travels around Earth every month, spending 1-3 days in each of the zodiac's constellations (houses). So regardless of which house is considered the 7th, the predicted Jupiter-Mars-Moon configuration occurs on average at least every 12-13 years. If the Moon wasn't in the proper house this year, it has been within the last few years and will be again in the next few years--over and over again.
Unfortunately I've not noticed any 12-13-year cycle of peace and love sweeping over our planet. Perhaps that state of affairs is awaiting, not some mystical alignment of the Moon and planets, but rather us Earthlings getting in "proper alignment" with each other. And that, it seems, requires not wishful or magical thinking or futile faith in a pseudoscience like astrology, but resolve and hard work from us all.
- Next Two Weeks: Average sunrise: 6:59 a.m.; average sunset: 7:58 p.m. (for Waco, TX)
* Monday evening (Apr. 11) the crescent Moon is just to the upper left of Taurus' beautiful Pleiades star cluster low in the west soon after dark.
* Wednesday morning (Apr. 13) Mars passes to the lower left of Neptune low in the southeast before dawn. (Seeing faint Neptune requires a telescope but now Mars can help find it.)
* Friday evening (15) the Moon is above Saturn with Gemini's brightest stars, Pollux and Castor, to their upper left.
* Moon is at 1st quarter Apr. 16, and above Leo's brightest star, Regulus, Apr. 18.
* The evening of Apr. 21 Jupiter chases the Moon across the sky all night, then the next night the Moon chases Jupiter, with Virgo's brightest star, Spica, chasing them both.
* The bright Moon interferes with seeing the Lyrid meteor shower which peaks the morning of Apr. 22.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Jupiter, the brightest starlike object now visible, is seen all night, in the east in the evening and in the west in the morning. Saturn is high in the west in the evening and sets after 2 a.m. Morning: Mars, rising 3 hours before the Sun, is seen in the southeast while Mercury barely peaks above the eastern horizon shortly before sunrise. Venus is in the Sun.
March 26, 2005
Partial Solar Eclipse to be Visible Here
The afternoon of April 8 the Moon takes a bite out of the Sun, producing a partial solar eclipse in our part of the world. The eclipse begins here at 4:20 p.m. and ends by 6 p.m. During maximum eclipse at 5:10 p.m. we'll see 20% of the Sun eclipsed.
Eclipses of the Sun occur during new Moons when the Moon passes between Earth and Sun, briefly blocking all or part of the Sun from view. When the alignment is exact the Sun is totally covered, producing a total solar eclipse, which is what will occur over a narrow strip across the Pacific Ocean. When the alignment is almost exact the Moon covers part of the Sun, resulting in a partial eclipse, which is what we'll see.
There is a new Moon every month when the Moon passes between the Earth and Sun, yet we don't have a monthly solar eclipse because usually the Moon passes above or below the Sun. This eclipse is a rare type although we won't witness its rare nature. While it will be total over a part of the Pacific, it will be what is called annular over parts of Central and South America.
The Sun and Moon appear about the same size because the Sun is 400 times larger than the Moon and by coincidence is also about 400 times further away. But since the Moon's orbit around Earth is elliptical rather than circular, once each orbit the Moon is closest to Earth (called perigee) and looks a little larger, and once is furthest away (called apogee) and looks smaller.
During most solar eclipses the Moon's distance is such that it appears slightly larger than the Sun and can completely cover it. But when a solar eclipse occurs at or near apogee, the Moon isn't quite large enough to completely cover the Sun, producing an annular eclipse which makes the eclipsed Sun look like a fiery ring as the Moon blocks out most of the Sun's central section.
This time, by a rare circumstance of distances and timing, when the path of totality over the Pacific reaches land, the total eclipse becomes annular, so some Central and South Americans will see the Sun as a breath-taking ring of fire.
I hope you enjoy our April 8 partial eclipse over Texas, but remember: never look directly at the Sun, even briefly. You can see the eclipse with a pin hole projector. Place a small hole in a piece of heavy paper or cardboard, then hold it in front of a light colored surface. (Don't look through the hole.) Move it nearer or farther from the surface until a tiny image of the Sun comes into focus, then look for the Moon's bite out of the Sun.
- Next Two Weeks: Average sunrise: 6:16 a.m.; average sunset: 6:49 p.m. (for Waco, TX)
* This morning (Mar. 26) the large gibbous Moon is below Jupiter low in the west, and tonight is above the star Spica in the east.
* Wednesday morning (Mar. 30) the Moon is to the right of the star Antares in the south.
* Friday (Apr. 1) the Moon is at 3rd quarter.
* The morning of Apr. 3 the crescent Moon is to the lower right of Mars in the southeast, then below the red planet the next morning.
- Naked-eye Planets: The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation. Jupiter rises at sunset, is in the sky all night, and sets at sunrise. Saturn, high in the south in the evening, sets well after midnight. Mars, seen in the morning, is up by 4 a.m.
- Astronomy Class: The Stargazer's four-session "Learning the Night Sky" class is Mar. 28-31 from 7:30-9:30 p.m. The cost is $25 per person with family discounts and scholarships available. Call or email for information or to register.
March 12, 2005
Just as the name Frankenstein elicits visions of monsters, the name Einstein is synonymous with genius, and with good reason. His theories of relativity revolutionized our understanding of the cosmos perhaps more than anyone before or since.
Born in Ulm, Germany, March 14, 1879, Albert Einstein died 50 years ago in Princeton, NJ, April 18, 1955, at 76. In one decade he shook the foundations of physics and cosmology with theories so complex that most of us have difficulty grasping them.
Anyone can come up with a theory: There's life on Mars. The Apollo 11 Moon landing was faked. The Moon is made of cheese. A theory is just a proposed explanation for some phenomenon.
When tested by scientific methods, some theories prove to be preposterously wrong, like the theory that intelligent beings dug canals on Mars. Some offer partial explanations, like Copernicus' theory of a Sun-centered cosmos and Isaac Newton's theories of gravity. And some, like Darwin's theory of evolution and Einstein's relativity theories continue to find strong support.
In 1905 Einstein published his Theory of Special Relativity which deals with high-speed motion, and in 1915 his Theory of General Relativity dealing with gravity. Humans had always thought of space and time as constants, fixed and unchanging, but Einstein, by thinking way outside the box, realized that it's the speed of light that's constant, not space or time. High speeds (vastly faster than humans can generate) and strong gravity can alter time and space. Time can speed up or slow down--not just seem to, but actually pass at different rates--and gravity can warp and stretch space.
If his ideas boggle your mind, don't feel bad. Even scientists of his day struggled with them. Since changes in time and space aren't apparent in everyday life they defy our common sense, yet the theories continue to be borne out by scientific tests.
Eventually even Einstein's theories will be modified with new evidence and new ideas. But just as he stood on the shoulders of giants before him, the shoulders of the 20th century genius have, for the last 100 years, enabled scientists to see farther into the workings of nature than most of our minds can comprehend.
- Next Two Weeks: Average sunrise: 6:34 a.m.; average sunset: 6:39 p.m. (for Waco, TX)
* Monday evening (Mar. 14) the crescent Moon is below Taurus' Pleiades star cluster in the west.
* Tuesday evening (Mar. 15) the Moon is above the cluster and to the lower right of Taurus' brightest star, Aldebaran (the "red eye of the bull") and the V-shaped Hyades star cluster.
* The Moon is at 1st quarter Thursday (Mar. 17).
* The evening of Mar. 19 the Moon is to the upper left of Gemini's brightest star, Pollux, and to the upper right of Saturn high in the southwest.
* Mar. 20 is the vernal equinox, the first day of spring in the northern hemisphere.
* The March 25 full Moon, called Crow Moon, Sap Moon, Lenten Moon and Egg Moon, is above Jupiter with Virgo's brightest star, Spica, below Jupiter.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Mercury, now at its highest above the setting Sun, is just above the western horizon 45 minutes after sunset, well below the crescent Moon. Saturn is high in the southwest, and Jupiter rises just after 8 p.m. Morning: Mars is low in the southeast with Jupiter low in the southwest.
- Astronomy Class. The Stargazer's 5-session "Learning the Night Sky" class will be Mar. 28-31 from 7:30-9:30 p.m. The cost is $25 per person with family discounts and scholarships available. Call or email for information or to register.
February 26, 2005
The Moon Hides Antares
In the wee hours of March 3 there will be an occultation and you're invited. But don't expect a secret gathering of astrologers or members of an Earth-centered religion. This event will be conducted by Mother Nature herself.
The 3rd quarter Moon will occult (pass in front of) Scorpius' brightest star, Antares, shortly before dawn. The star will disappear behind the Moon about 4:28 a.m. and reappear about 5:48 a.m. These times are for Central Texas, and will be later to the east and earlier to the west. For example, the events occur some 20 minutes earlier in far West Texas.
The Moon, which rises at 1:10 a.m., will be in the south southeast as the occultation begins and in the south as it ends. The disappearance will be hard to see as the star slips behind the Moon's bright illuminated side, meaning that binoculars or a telescope will be needed. You might even want to skip the disappearance for an extra hour of sleep.
But you won't want to miss the reappearance when the star emerges from the Moon's shadowed side, making it easier to see and more dramatic in appearance. The reappearance occurs an hour before sunrise so dawn may be starting to break, but this shouldn't interfere with viewing.
Stars are huge, and Antares is much larger than our Sun. Yet they are so far away they still only look like points of light rather than tiny spheres. When Antares reappears it won't emerge gradually but rather will blink on instantly--as quickly as a light bulb when you flip a switch. So as the time approaches, keep watching constantly.
If you have a camcorder with a tripod it's easy to record so you can watch it again (and show it to sleepyheads who didn't get up for it). Zoom out to find the Moon, then zoom in all the way and start recording. The Moon and Earth slowly move so you'll need to re-center the Moon every few minutes to keep it in view.
There are other things to see while waiting for Antares' reappearance. Jupiter, to the Moon's upper right, is the brightest object high in the southwest, and Mars, to the Moon's lower left, is low in the southeast. While not as bright as Jupiter, Mars is still brighter than the surrounding stars and should be easy to identify.
Although it's still late winter, the early morning sky gives a preview of the constellations seen in the evening skies of late spring and early summer, such as Scorpius, Sagittarius, Libra and Ophiuchus. Unfortunately glare from the half-illuminated Moon will wash out all but the brighter stars, but it won't interfere with seeing the planets.
- Next Two Weeks: Average sunrise: 6:51 a.m.; average sunset: 6:30 p.m. (for Waco, TX)
* Tomorrow (Feb. 27) morning Jupiter is above the Moon with Virgo's brightest star, Spica, to their left.
* The morning of Mar. 6 the crescent Moon is below Mars low in the southeast before dawn.
* The Moon is new Mar. 10.
* The evening of Mar. 11 the thin crescent Moon is to the upper left of Mercury near the western horizon 45 minutes after sunset.
- Other Naked-eye Planets: (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.) Mercury, still hidden in the glare of the setting Sun, will be at its best for 2005 in mid-March. Saturn, high in the southeast in the evening, sets at 4 a.m.
February 12, 2005
Pluto Discovered 75 Years Ago This Month
"Dr. Slipher, I've found your Planet X." With those words spoken 75 years ago this month, 24-year-old Clyde Tombaugh announced his discovery to his superior, Dr. V.M Slipher, at Arizona's Lowell Observatory. What he had discovered on Feb. 18, 1930, was the ninth planet, eventually named Pluto.
Barely a year earlier Tombaugh was a bright Kansas farm boy who in his spare time made telescopes and observed the night sky as an avid amateur astronomer. He graduated from high school in 1925 with ambitions of college when he could afford it.
In 1928 a developing bumper crop of wheat and oats on the family farm gave promise that he might finally start college in the fall, but a summer hail storm destroyed the crop, and with it, his dreams of college. It convinced him that farming was like gambling. His father had once quipped, "My occupation is a wheat farmer, but I milk cows and raise chickens for a living."
Wanting a career less dependent on the whims of the weather, Tombaugh used his self-taught observational skills and willingness to work long hours in a cold observatory at low wages to land a job at Lowell Observatory in January 1929.
The observatory was initiating yet another search for a planet believed by some to be orbiting beyond Neptune. Tombaugh was hired to take long-exposure photos of selected areas of the night sky which professional astronomers would then examine for evidence of the suspected planet. The astronomers soon found the job of examining photos extremely tedious and time-consuming, and turned that part of the project over to Tombaugh as well. So on photos he took Jan. 23 and 29, he made his historic discovery.
Ironically, Pluto had been captured on photos taken in 1915, but no one recognized it as a new planet. Looking back, Tombaugh suspects that had the astronomers done the examinations of his photos in 1930, they would have lacked the time and diligence he used to spot the faint planet among the thousands of stars on the photos, and the discovery would have been missed once again. But had they noticed it, they rather than he would have been credited with Pluto's historic discovery, and the now-famous Clyde Tombaugh would have remained an obscure observatory technician.
He did finally get to college, and he too became a professional astronomer. Born Feb. 3, 1906, Tombaugh died in 1997 at age 90.
- Next Two Weeks: Average sunrise: 7:06 a.m.; average sunset: 6:19 p.m. (for Waco, TX)
* Tuesday evening (Feb. 15) the 1st quarter Moon is to the lower right of the Pleiades star cluster; although the Pleiades is normally seen easily with naked eyes, binoculars will be helpful due to the glare of the Moon.
* Like a month ago, the evening of Feb. 19 the gibbous Moon is resting in a "cradle" formed by Saturn (lower right) and Gemini's brightest stars, Pollux and Castor, high in the east.
* The Feb. 23 full Moon is called Snow Moon, Hunger Moon and Wolf Moon.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Saturn is the bright creamy-colored object high in the east, not to be confused with Sirius, the night sky's brightest star in the southeast. Morning: Venus, fast sinking into the morning Sun, rises just a half-hour before sunrise. Mars is the bright reddish object in the southeast with the slightly brighter reddish star, Antares, to its upper right. Jupiter is the brightest object high in the southwest.
January 29, 2005
Future of Hubble Space Telescope in Jeopardy
To be or not to be? That seems to be the question facing the venerable Hubble Space Telescope (HST). The 15-year-old orbiting observatory needs another maintenance visit to extend its life and upgrade old equipment. Its gyroscopes, batteries and guidance sensors, all essential for continued operation, are expected to wear out within 2-4 years.
In addition, two new state-of-the-art science instruments are already build and ready for installation. These instruments, according to the National Academy of Sciences, would greatly improve the HST's scientific sensitivity, and from them "a broad range of new discoveries would be expected from Hubble."
What's needed is another servicing visit from a space shuttle crew to replace aging equipment and install the new instruments, something that's been done in 1993, 1997, 1999 and 2002. A mission was in the works until the tragic Columbia disaster in 2003 led NASA to ground the shuttles pending a thorough study.
In mid-2004, to the dismay of the scientific community, NASA Administrator Sean O'Keefe announced plans to abandon the HST on the basis that another servicing mission would be too risky for astronauts. After pressure from equally dismayed members of congress and the public, he agreed to reconsider.
The National Academy of Sciences conducted a risks/benefits analysis looking at (1) HST's continuing scientific value, (2) the risks to astronauts, and (3) the feasibility of using robots.
It was determined that HST's many advantages over Earth-based telescopes make it "the most powerful optical astronomical facility in history" and that it can continue to make "profound and unique contributions" to our understanding of the universe, including galaxies, star formation and black holes. Thus, its continuing scientific value is enormous.
The NAS analysis indicates that while all shuttle missions pose risks for astronauts, a mission to HST poses no greater risk than missions to the International Space Station, a level of risk NASA, congress and the public find acceptable.
Finally, said NAS, a robotic mission would be more expensive, would likely fail, and could probably not be developed in time to save HST from permanent damage that would render it useless.
In conclusion, NAS recommended that NASA proceed with the servicing mission as soon as feasible after the shuttles resume flight. But now it is reported that the Bush administration plans to eliminate funding for the mission from its 2006 budget--a death sentence for the popular Hubble Space Telescope.
- Next Two Weeks: Average sunrise: 7:19 a.m.; average sunset: 6:07 p.m. (for Waco, TX)
* Late tomorrow evening (Jan. 30) the Moon and Jupiter rise near each other after 11 p.m., pass closest to each other at 2 a.m., and are high in the southwest by morning.
* Tues. morning (Feb. 1) Virgo's brightest star, Spica, is between Jupiter and the Moon.
* Wed. (Feb. 2) is Groundhog Day and Candlemas, the cross-quarter day celebrating the middle of winter, and the Moon is at 3rd quarter.
* Fri. morning (Feb. 4) a crescent Moon is to the lower left of Scorpius' bright reddish star, Antares, with reddish Mars further to the lower left.
* The morning of Feb. 5 the crescent Moon is below Mars.
* The Moon is new Feb. 8.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.) Morning: Venus is slipping into the morning Sun. Mars is in the southeast before dawn with Jupiter in the southwest. Evening: Saturn is high in the east in the evening and sets before dawn.
January 15, 2005
2005 Stargazing Highlights
Astronomically, 2005 is starting off with a bang as the faint but interesting Comet Machholz graces our evening skies. And as you read this, the Huygens space probe will (hopefully) be descending to the surface of Saturn's largest moon, Titan, yielding data to help us better understand conditions which led to life on our planet some 3 billion years ago.
So what else can we expect this year? Remember the excitement about Mars in 2003? Well, it's coming back--not as dramatically as two years ago, but nearly. Now in the morning sky, Mars is gradually brightening, will move into the evening sky by late summer, and will appear largest and brightest in mid-fall.
Most years bring interesting close pairings of the Moon, planets, bright stars and other objects, and 2005 will be no exception. This year's dozen or so pairings feature the Moon, all five naked-eye planets and even two star clusters. Three of the pairings will be more than just close as the Moon occults (passes in front of) the star, Antares, in March, May and July.
There will be a slight partial solar eclipse Apr. 8 and lunar eclipse Oct. 17, but neither will be much to get excited about. However, with no Moon interference, it should be a good year for August's Perseid meteor shower, usually one of the year's best.
In early July the space probe, Deep Impact, will plunge into Comet Tempel 1, blasting cometary debris into space. This primordial material might reveal more insights into the formation of our solar system 5 billion years ago.
Finally, the Central Texas Astronomical Society's new Paul Meyer Observatory, located near Clifton, opens this year.
- Next Two Weeks: Average sunrise: 7:28 a.m.; average sunset: 5:48 p.m. (for Waco, TX)
* Comet Machholz, a binocular comet barely visible to naked eyes under dark skies, passes near the fairly bright star, Algol, tomorrow evening (Jan. 16), then passes the brighter star, Alpha Persei, Jan. 21. Unfortunately, the Moon will make seeing the comet more difficult.
* The Moon is at 1st quarter Mon. evening (Jan. 17).
* Gemini's two brightest stars, Pollux and Castor, along with brighter Saturn, form a "cradle" for the gibbous Moon the evening of Jan. 23.
* The Jan. 25 full Moon is called Old Moon, Cold Moon and Moon After Yule.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation on its axis.) Saturn is up virtually all night--low in the east in the evening, high in the south at midnight, and low in the west in the morning. Jupiter and Mars are prominent in the morning with Jupiter high in the south and Mars low in the southeast. Mercury and Venus are sinking near the morning Sun.
- Public Session. The Central Texas Astronomical Society's annual "Learn to Use Your Telescope" session is tonight (Jan. 15) at Hewitt City Park beginning at 5 p.m. Open to the public, participants are invited to bring their own telescopes for hands-on instruction. For more information call Dick Campbell at 254-857-8310.
- Stargazer's 15th Anniversary. Stargazer has appeared every-other-week in the Waco Tribune-Herald since Jan. 20, 1990. It also appears in some 35 other Texas newspapers. As a column of informative entertainment about the pleasures of stargazing, your continued readership is appreciated, and your emails, comments and questions are welcome.
January 1, 2005
Comet Machholz Greets the New Year
Happy New Year! The Stargazer hopes 2005 proves to be your best year yet. Astronomically, Mother Nature is doing her part by offering a New Year's treat--Comet Machholz.
Discovered last Aug. 27 by amateur astronomer Don Machholz, the comet, officially named Comet Machholz, C/2004 Q2, became visible in our skies in December and will be at its best this month.
Although is not especially bright and lacking the prominent tail for which comets are known, Machholz is still interesting. It is visible to naked eyes under dark skies, and can be seen in binoculars from urban areas, although not yet easily. But what it lacks in brightness it makes up for in size. Passing relatively near Earth (nearly as close as Venus gets to us), it appears larger than most comets--about the size of a full Moon.
Conveniently, it is visible in the evening as the skies darken, and remains in view well past midnight. Over the next few nights it passes just over 10 degrees to the upper right of the bright reddish star, Aldebaran, the "eye of the bull." (The width of your fist held at arm's length is 10 degrees.) At 8 p.m., Aldebaran is 5-6 fists above the eastern horizon, above the familiar Orion.
The evenings of Jan. 6, 7 and 8, with the comet at its brightest, it passes less than 3 degrees (five moonwidths) to the right of the Pleiades star cluster. If it has developed a visible tail by then, the tail will be pointed toward the Pleiades, producing a beautiful sight in binoculars.
The evening of Jan. 16, Machholz is in Perseus and passes less than 2 degrees below the star, Algol, then Jan. 21 only 3 degrees above the brighter star, Mirfak (Alpha Persei). By February the comet will have dimmed notably as it swings past Cassiopeia. Mar. 1-17 it passes near Polaris, the North Star, and then through the Big Dipper in late April and early May, by which time it will be quite faint.
For more detailed information see skyandtelescope.com.
- Next Two Weeks: Average sunrise: 7:28 a.m.; average sunset: 5:36 p.m. (for Waco, TX)
* Today (Jan. 1) Earth reaches perihelion, when it is nearest the Sun in its elliptical orbit.
* The Moon is at 3rd quarter Monday (Jan. 3).
* The mornings of Jan. 6-11, reddish Mars passes to the upper left of the slightly brighter reddish star Antares, providing an opportunity to see how Antares, which means "rival of Mars," got its name.
*Fri. morning (Jan. 7), the crescent Moon, Mars and Antares form a triangle low in the southeast.
* The morning of Jan. 8, near the southeastern horizon 45 minutes before sunrise, Mercury is just above brilliant Venus with a crescent Moon to their upper right and the Mars-Antares pair 12 degrees above the Moon.
* The morning of Jan. 13, Venus and Mercury pass less than a moonwidth from each other.
* The Moon is new Jan. 10.
- Naked-eye Planets. (The Sun, Moon and planets rise in the east and set in the west due to Earth's west-to-east rotation.) Evening: Saturn, rising at sunset, is in the sky all night. Morning: Mercury and Venus (the "evening star") are near the southeastern horizon just before dawn, with Mars a bit further up and much brighter Jupiter high above them.
- Astronomy Class. The Stargazer's 4-session "Learning the Night Sky" class will be Jan. 3-6 from 7-9 p.m. The cost is $25 per person with family discounts and scholarships available. Call or email for information or to register.