| 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.
Dec. 21, 2002: A New Star in the Sky
Dec. 07, 2002: What Is It About Stargazing?
Nov. 23, 2002: Venus and Mars Rendezvous in the Morning Sky
Nov. 09, 2002: Buying a Telescope for a Holiday Gift
Oct. 26, 2002: Andromeda's Rescue
Oct. 12, 2002: The Water World
Sep. 28, 2002: The Night Sky in Music and Poetry
Sep. 14, 2002: Seasons and the Moon
Aug. 31, 2002: Some Interesting Sights the Next Two Weeks
Aug. 17, 2002: Venus, the "Evening Star"
Aug. 03, 2002: Perseid Meteor Shower
July 20, 2002: Sagittarius' Tea Party
July 06, 2002: Listening to the Sky
June 22, 2002: Year's Midpoint and Earth at Aphelion
June 08, 2002: Partial Eclipse of the Sun
May 25, 2002: Venus and Jupiter Finally Meet
May 11, 2002: Spring Sky: Cosmic Baseball
Apr. 27, 2002: Continuing Dance of the Planets
Apr. 13, 2002: Dazzling Planetary Alignment
Mar. 30, 2002: McDonald Observatory: Texas' Astronomical Jewel
Mar. 16, 2002: Central Texas Observatory Update
Mar. 02, 2002: The Great Winter Arc
Feb. 16, 2002: Moon Occults Saturn
Feb. 02, 2002: Preview of 2002
Jan. 19, 2002: Moon Tour of 3 Planets
Jan. 05, 2002: Upcoming Stargazing Opportunities
December 21, 2002
A New Star in the SkyCenturies ago a new star appeared in the sky--a mysterious star that baffled the wise men of the day. No, I'm not talking about the Star of Bethlehem--that's still a mystery. In 1054 AD, Oriental astronomers reported seeing an extremely bright new star in the constellation Taurus--a star that grew brighter than Venus and was visible even during the day. Within a few weeks, however, it faded and disappeared. Astronomers now know it was a supernova explosion--the final, cataclysmic death throes of a star. Under dark skies and with optical aids, we can still see the cloudy supernova remnants, called the Crab Nebula. In most telescopes it appears as a faint, wispy smudge of light, but astrophotography reveals eerie-looking lines within the nebula, giving it its name. In most amateur scopes, it's not exactly dazzling, and its faintness makes it difficult to see at all. The awe is in the realization of what one is seeing--the outer remains of a now dead star. Adding to the fascination is a rapidly rotating neutron star, called a pulsar, embedded within the cloud. Only a few miles in diameter and not visible in most scopes, this pulsar is the corpse of the collapsed and now dead star. Jan. 4 Saturn will be directly in front of the Crab Nebula. While this might be a good viewing opportunity, Saturn's glare could wash out the faint nebula. If you have a telescope, now is a good time to look for the elusive, faint nebula, currently about two moonwidths to Saturn's upper right. Even if can't see the Crab Nebula, Saturn is quite dazzling by itself.
- Telescope Instruction: The Central Texas Astronomical Society will hold two free, public sessions on "Learning How to Use Your New Christmas Telescope." The first is an indoor session at the Waco-McLennan Co. Public Library (basement) from 6:30-8:30 p.m. Thursday, Jan. 2. The second, an "under-the-stars" session, is at Hewitt City Park from 6:30-8:30 p.m. Saturday, Jan. 4. Participants are invited to bring their telescopes to either or both sessions for personalized, hands-on assistance and instruction. For more information, call Johnny Barton at 254-881-2125 or Dick Campbell at 254-857-8310.
December 7, 2002
What Is It About Stargazing?There are times--especially when I'm under a beautiful night sky--I find myself wondering: Why isn't everyone a stargazer? Then in more objective moments I ask myself: What is it about stargazing I find so fascinating? What do I get out of seeing faint fuzzies in the night sky? Maybe I need to get a life! So, should everyone become a stargazer, or should I get a life? I suppose we could ask the same of any of our seemingly non-essential life interests, or avocations. What is it about watching birds, collecting rocks or stamps, gourmet cooking, hiking or climbing mountains--things that don't earn us a living? Perhaps Abraham Maslow's Needs Hierarchy can help here. Maslow says we have levels of needs, the more basic of which must be met before we can concern ourselves with higher level needs. Our most basic are physiological (hunger, thirst, shelter and the like) and security (a safe environment). When these are not adequately met, we have little interest in avocations as they typically don't contribute at this level. When survival and security needs are met, we then attend to social and self-esteem needs. Here avocations can contribute, such as when we join with kindred spirits who share our interest. But as much as I value time spent with my stargazing compadres, I, like many others, still often find myself engaging in my avocation in solitude--and finding fulfillment doing so. Enter Maslow's final needs level: self-actualization--developing latent potentials, expressing creativity, satisfying aesthetic needs, giving to others, connecting with things beyond oneself. And I've found stargazing meets many of these needs for me--opportunities for fascinating new learnings, beholding the beauty of the night sky, contemplating nature's wonders and pondering my part in this unfathomably enormous and mysterious cosmos. And it brings me full circle, back to wondering: Why isn't everyone a stargazer?
- ASTRO MILESTONES: Dec. 14 is the 456th anniversary of the birth of Danish astronomer Tycho Brahe (1546-1601), whose meticulous observations enabled Johannes Kepler to discover that planets circle the Sun in elliptical rather than circular orbits.
November 23, 2002
Venus and Mars Rendezvous in the Morning SkyOver the past few weeks astute morning stargazers are likely to have noticed the drama building low in the east involving two planets and a bright star. The brightest object is the "morning star" Venus, now rising two and a half hours before sunrise. Fainter than Venus, but still brighter than other surrounding stars, are the planet Mars and Virgo's brightest star, Spica. An hour before sunrise (around 6 a.m.) Venus is now 17 degrees above the horizon in the east southeast. (The width of your fist held at arm's length is 10 degrees.) Mars is 5 degrees above Venus with Spica 3 degrees to Mars' upper right. White Spica is slightly brighter than reddish Mars. This grouping is fun to see now, but it gets even more interesting over the next couple of weeks. Each morning the trio rises above the horizon four minutes earlier, and thus will be slightly higher than they were at the same hour the previous morning. As they get higher, the two planets gradually move further from Spica while moving nearer each other. Regular morning observers can watch Mars pull away from Spica and approach Venus as their changing positions will be noticeable from morning to morning. Next weekend provides an extra treat when a crescent Moon briefly joins the action. The Moon will be 9 degrees above Spica on Nov. 30. Then the next morning the Moon, Venus and Mars will form a triangle some 2 degrees on each side. Mars moves to within less than 2 degrees of Venus on Dec. 2 and spends nearly two weeks at that range. (The width of your index finger held at arm's length is 1 degree, the width of two full Moons.) Mars reaches its closest approach to Venus Dec. 6 when it closes to within one and a half degrees -- the width of three full Moons. The much fainter Mars will be to the upper right of Venus. After their rendezvous, the two will then move further apart. Venus will continue as the "morning star" well into next year while Mars has even bigger plans. In late Aug. 2003, the fiery red planet will pass closer to Earth than its been in -- well, some say many centuries, others say many thousands of years. Regardless of whose calculations are right, Mars will be closer -- and appear larger and brighter -- than at any time in our lifetimes.
November 9, 2002
Buying a Telescope for a Holiday GiftDon't look now but the gift-giving season is just around the corner. If a telescope is on your gift list that's one gift you might not want to put off until the last minute. If all you're looking for is a small, inexpensive scope, then the last minute might be OK since many department stores carry them. And these small scopes can be fun if you're aware of their limitations and don't have unrealistic expectations. But if you're looking to spend more for a higher quality scope (with an all-important sturdy mount), then you'll want to do some research. Ideally you will be able to visit a telescope dealer who can help educate you about your choices based on your intended uses. Dealers can offer a selection of types and price ranges, and give you instruction on using the scope you purchase. Unfortunately, unless you live in or near a large city like Austin, San Antonio, Houston or Dallas, you're not likely to find such a dealer. So what do you do? If your area has an amateur astronomy club, that can be a terrific resource. Attend one of their star parties where you can examine and look through a variety of scopes. Talk with the owners who don't mind questions like "How much did it cost?" In the Waco area, the Central Texas Astronomical Society is available. For contact information check their Web site at www.centexastronomy.org. If you live beyond central Texas, look for a club near you at www.skyandtelescope.com, selecting the Resources bar, then Clubs and Organizations. And while at that site you can print out "Choosing Your First Telescope" by selecting the How To bar, then Telescopes & Binoculars. Some department stores do carry more sophisticated (and expensive scopes) which is convenient, but don't be surprised if their personnel know little about the scopes they are selling.
- LEONID METEORS: This year's Leonid meteor shower, which peaks the night of Nov. 18/19, will be a "good news-bad news" event. The good news: this is expected to be one of the best Leonid storms in years. The bad news: the full Moon will be in the sky all night, greatly diminishing all but the brightest meteors. But it's still worth a look. Earth is predicted to encounter the first of two dust trails about 10 p.m. Nov. 18 with North America poorly positioned to see much activity. The second encounter is expected 6 hours later about 4 a.m. Nov. 19 for which we will be well positioned. For more information, see the International Meteor Organization's Web site at www.imo.net.
- ASTRO MILESTONES: Nov. 20 is the 113th anniversary of the birth of American astronomer Edwin Hubble (1889-1953), discoverer of the existence and nature of galaxies, and for whom the Hubble Space Telescope is named.
October 26, 2002
Andromeda's RescueOnce again it's time for the cosmic hero, Perseus, to make his annual rescue of the beautiful sky princess, Andromeda. Yes, it's a rerun, but aren't some of the best shows on TV reruns? Just as I never tire of seeing Andy Griffith, Archie Bunker, Mr. Spock or Dr. Who, I always welcome the cast of Andromeda's Rescue back each year as they return to the fall's evening sky. The story and its famous characters come from Greek mythology and have been around well over two thousand years. It starts with the beautiful but vain Queen Cassiopeia. Her incessant bragging about her own beauty was bad enough, but when she boasted that her daughter, Princess Andromeda, was more beautiful than the sea nymphs, that was more than Neptune, the god of the seas, could take. He kidnaped Andromeda and chained her to an island to be devoured by the sea monster, Cetus. Enter the hero, Perseus. Like all good heroes, he couldn't stand by and let the helpless maiden-in-distress be eaten. So with help from some friendly gods, he came up with a plan. There was a woman named Medusa who was so hideously ugly -- her head had snakes for hair -- that all who looked at her were so petrified with terror that they turned into stone. Using a magic shield provided by the gods, Perseus cut off Medusa's head, taking care not to look at her, and put it in a sack. Then riding across the skies on Pegasus, a flying horse also furnished compliments of the gods, Perseus got to the island just in time. He pulled Medusa's horrible head from the sack, showed it to Cetus, and watched the sea monster turn into stone and sink harmlessly to the bottom of the sea. After discarding Medusa's head, Perseus and Pegasus swooped down and rescued the grateful Andromeda, after which the princess and the hero were married and reportedly lived happily ever after. As an afterthought, I've wondered if Perseus ever wished he'd kept Medusa's head to show his vain and probably meddlesome new mother-in-law, Cassiopeia. Cepheus, a constellation of mostly faint stars, is now high in the north. Cassiopeia, with somewhat brighter stars shaped like a "M" is to Cepheus' right. Pegasus (with the well known Square of Pegasus) is high overhead. Andromeda occupies the area between Cassiopeia and Pegasus. Perseus is somewhat lower in the northeast, and Cetus lower in the southeast. Medusa, represented by the variable star, Algol, is in the constellation Perseus. Those viewing from dark skies can see the Milky Way running through Perseus, Cassiopeia and part of Cepheus.
- TIME CHANGE: Tonight before retiring, remember to set all your clocks (house and car), watches, cell phones and other time-keeping devices back one hour ("fall back") to standard time. (Doesn't this get to be a pain?)
- ASTRO MILESTONES: Oct. 29th is the 346th anniversary of the birth of Edmund Halley (1656-1742), English astronomer of Halley's Comet fame.
October 12, 2002
The Water WorldThe evenings of October are a good time to see most of the night sky's water world, a region in which all the constellations relate to water: a river, a person who carries water, a shore bird, and six critters who live in the sea. It's a huge region stretching from Capricornus, which is next to the summer sky's Sagittarius, to Eridanus which is next to winter's Orion. Although one of the largest sky regions, it's also one of the faintest, composed mostly of stars that can be seen only under very dark skies. The entire region contains but one bright, 1st-magnitude star visible from our latitude. At the western end of the water world is Capricornus the Sea Goat, seen 40 degrees above the southern horizon at 9 p.m. (The width of your fist held at arm's length is about 10 degrees.) Capricornus is shaped like a huge boomerang or fat banana. Almost twice as far up in the south is the small Delphinus the Dolphin. With a little imagination, its half dozen stars actually resemble a tiny dolphin. Just to its lower left is Equuleus the Horse (which I regard as a seahorse since he lives in the water world). Don't bother trying to find Equuleus -- he's small, faint and doesn't look like a horse. Immediately above and left of Capricornus is the large Aquarius the Water Carrier, also composed of faint stars which really don't resemble anything recognizable. Beneath Capricornus is Piscis Austrinus the Southern Fish. Most of its stars are faint, but it does host the water world's only 1st-magnitude star, Fomalhaut (pronounced "foam-a-lot"). Right now Fomalhaut is 20 degrees above the horizon in the south southeast in the early evening. As the only bright star in this part of the sky, it's easy to spot. Just below Piscis Austrinus is Grus the Crane. Grus has a couple of moderately bright stars, but being near the horizon is rather difficult to see. Coming up in the east are Pisces the Fish and Cetus the Sea Monster (Whale). Pisces contains no bright stars and is difficult to see even under dark skies. Cetus does have a few brighter stars but is now low in the east. The water world's final constellation, Eridanus the River, is not yet above the horizon. Some of these constellations are probably unfamiliar -- had you heard of Equuleus or Eridanus? Three, however, are familiar -- Capricornus, Aquarius and Pisces. Since the Sun, Moon and planets pass through them, they are constellations of the zodiac (which astronomers call the ecliptic).
Sept. 28, 2002
The Night Sky in Music and Poetry
The night sky has long been a source of poetic inspiration -- probably as long as there's been poetry. Although somewhat poetry-challenged, even I recognize that poetry can give deeper, more powerful expression to aspects of life -- often mysterious and paradoxical aspects -- than ordinary spoken or written words. And good poets often capture in a few words more meaning than other writers achieve in paragraphs.
Well-known astronomy writer and comet discoverer David Levy compiled astronomical references by poets in his book More Things in Heaven and Earth, the title of which comes from Shakespeare's Hamlet: "There are more things in heaven and earth, Horatio, / Than are dreamt of in your philosophy." Here are a few of my favorites, some from Levy's book, some from other sources.
Joni Mitchell in her song "Woodstock" stated, "We are stardust...," a succinct and poetic way of saying that the heavy elements in our bodies were formed in supernova star explosions. A Surbian poet expands on the same theme: "Be humble for you are made of dung. Be noble for you are made of stars."
John Denver's popular song "Rocky Mountain High" was written after a night of stargazing with friends. The line, "I've seen it rainin' fire in the sky," is his poetic description of being awestruck by an especially bright meteor.
The 19th-century American poet Emily Dickinson used stars, including a member of the Pleiades star cluster, to express the emptiness felt at the loss of a friend, even when in the midst of a crowd: "I had a star in heaven; / One Pleiad was its name, / And when I was not heeding / It wandered from the same. / And though the skies are crowded, / And all the night ashine, / I do not care about it, / Since none of them are mine."
And my final favorite is in Max Ehrmann's well-known 1948 Desiderata: "You are a child of the universe, no less than the trees and the stars, you have a right to be here."
- ASTRO MILESTONES: Oct. 4 is the 45th anniversary of the birth of the Space Age with Russia's 1957 launch of Sputnik I, the first human-made object placed in Earth orbit.
Sept. 14, 2002
Seasons and the MoonWhile calendars show fall beginning Sept. 23, the Central Time Zone (and points west) will seem to get a slight head start on the season this year. Fall actually begins Sept. 23 at 4:56 Universal Time (formerly called Greenwich Mean Time), but while that's early Monday morning in Greenwich, England, it will still be 11:56 p.m. Sunday night (Sept. 22) here in Texas. Most folks are well aware of the seasons and what they mean for our weather, but many don't know why they come about. Some think it has to do with Earth's proximity to the Sun -- that summer occurs when we're closer to the Sun, and winter when we're farther away. While that seems plausible, it's incorrect. If it were true, the northern and southern hemispheres would have the same seasons at the same time. But they don't -- they experience exactly opposite seasons. As we begin autumn, with leaves turning colors as they fall from trees, southern hemisphere plants are beginning to burst forth with new leaves and flowers of spring. (Anyone want to give me a free trip to New Zealand for the next few months?) Fall in the northern hemisphere (and spring in the southern hemisphere) begins the moment the Sun crosses the celestial equator (an extension of Earth's equator outward) from the northern to the southern celestial hemisphere. From then until the beginning of spring, our hemisphere will be tilted away from the Sun. For three more months, our days will grow shorter, yielding fewer hours of warming sunshine, and the sunshine we do get will strike our part of the planet at an increasingly greater angle, allowing less warmth to reach the surface. (The exact opposite is happening "down under" as they are getting warmer.)
Earth's seasons have everything to do with our planet's tilt on its axis. The origin of this tilt goes back billions of years, and curiously may share an origin with the Moon. Many astronomers think our Moon formed from a colossal collision between Earth and a large asteroid (or small, Mars-sized planet) over 4 billion years ago when our solar system was young. Upon impact material from the Earth's outer crust and from the impacting object were blasted into Earth orbit. At first this debris distributed itself around Earth as a ring, but over millions of years, this debris coalesced into the single, solid body we now know as our Moon. According to one theory, prior to this Moon-forming impact, the young Earth orbited the Sun in a relatively perpendicular (upright) position. The enormous impact, however, knocked Earth a bit wacky, leaving it at a 23 1/2 degree tilt on its axis. And were it not for this tilt, we wouldn't have seasons as we know them. And without seasons, life on Earth would have evolved quite differently, and the species we call homo sapiens -- namely us -- may or may not have even evolved at all.
- Astro Milestones: Sept. 23 marks the 156th anniversary of Johann Galle and Heimrich d'Arrest's discovery of the planet Neptune from Germany's Berlin Observatory in 1846. Their finding was based on the accurate position-calculations of Urbain Jean Joseph Leverrier of France.
August 31, 2002
Some Interesting Sights the Next Two WeeksThe next couple of weeks promise some interesting sights for both evening and morning stargazers, and for naked-eye, binocular and telescope viewing. The Moon and several planets will be prominent players in these sky shows. First, events for evening stargazers. Venus still dominates the sky after sunset as the lovely "evening star." Each night it now appears slightly lower and sets a few minutes earlier -- currently just over an hour and a half after sunset. As it moves nearer Earth, it's becoming even brighter, and seen through a telescope (even a small one), larger and more crescent-shaped, looking like a tiny Moon. Tonight Venus is within 1 degree of Virgo's bright star, Spica, low in the west after sunset. (The width of your index finger held at arm's length is 1 degree.) Even though the whitish, 1st-magnitude Spica is the night sky's 16th brightest star, it pales next to brilliant Venus. Mercury, which orbits the Sun every 88 days, is very low in the west, and getting lower each night. It now sets less than an hour after the Sun, so begin looking soon after sunset, 18 degrees to the lower right of Venus. (The width of your fist held at arm's length is 10 degrees.) You'll need a clear view down to the western horizon. The evening of Sept. 9, Venus, Spica and a crescent Moon will form a triangle low in the west soon after dusk. Spica will be nearest the horizon (and the most challenging to see) with the crescent Moon above it and Venus to the star's upper left. The evening of Sept. 12, a nearly quarter Moon will be to the upper right of Scorpius' brightest star, Antares, in the southwest. While the reddish, 1st-magnitude Antares is the 15th brightest star, the Moon's glare will make it difficult to see. All of these events can be seen with naked eyes although binoculars will enhance some of the views, and might be needed for spotting Mercury. And now for early-bird morning stargazers. Perhaps you already noticed the Moon to the left of Taurus' brightest star, Aldebaran, this morning. Tomorrow morning it will be above Saturn. Jupiter is now moving past Cancer's beautiful Beehive star cluster (also known as M44 and Praesepe) low in the east before sunrise. While this will be fun to watch each morning for the next week or so, they will be closest Wednesday with Jupiter to the cluster's right and a crescent Moon above them. To naked eyes the Beehive appears as an easily-missed, subtle patch of light about the size of a full Moon. But when viewed through binoculars, it's easy to see why it's called the Beehive -- a dazzling swarm of several dozen individual stars pops into your field of view. Actually containing over 200 stars, the Beehive is one of our nearest neighboring star clusters at a distance of 522 light years. Finally, here's one for early-birds with at least moderately-sized telescopes and very dark skies. Saturn is still near the faint and difficult-to-find Crab nebula -- a cosmic cloud-like remnant of the cataclysmic death of a giant star, called a supernova. Observed by Chinese and Japanese astronomers and others in the year 1054, this star's dying explosion was brighter than Venus for a few weeks. In a few days after the Moon has moved past the area, look for this exotic and now elusive nebula about 4 degrees to Saturn's upper right.
- FRIDAY THE 13TH: Sept. 13 is another Friday the 13th which we have once, twice, or even occasionally three times each year. Regarded as unlucky by the superstitious in our society, others ascribe bad luck to other weekdays and numbers. According to Guy Ottewell's Astronomical Calendar, some South American societies consider Tuesdays as unlucky while in Italy the number 17 is unlucky. So perhaps Friday the 13th will be unlucky only if you choose to make it such.
August 17, 2002
Venus, the "Evening StarSince early spring Venus has been the brilliant "evening star" in the west. As seen from Earth, our nearest neighboring planet is brighter than any star or other planet. Aside from an occasional fireball meteor, only the Sun and Moon are brighter, and it will be at its very brightest the end of September when it passes nearer Earth. Venus, which orbits closer to the Sun than Earth does, is never seen far from the Sun. As the "evening star," it's always low in the west setting soon after the Sun, and when the "morning star," it shines low in east shortly before sunrise. Currently at its maximum apparent distance from the setting Sun, called greatest elongation east, Venus is 46 degrees from the Sun, and sets 2 hours after sundown. To the naked eye, Venus looks like a star-like point of light, hence its designation as the evening or morning star. However a telescope reveals its discernible round shape. As with all planets and moons in our solar system, Venus doesn't emit light, but is illuminated by light from our Sun. And like our Moon we see Venus go through phases. For the past few months it has appeared in telescopes like a tiny gibbous Moon, less than full but more than half illuminated. It is now half illuminated, looking like a tiny quarter Moon. Over the next few weeks, it will grow increasingly crescent and larger as it passes between the Earth and Sun. After sinking into the Sun in October, it becomes the "morning star" in November. Because of its phases Venus played an important role in the Copernican revolution and helped put us Earthlings in our more-nearly proper place, cosmically speaking. Before the revolution, we believed Earth (and we) were at the center of the cosmos with the Sun, Moon, planets and stars revolving around us. And being at the center, we assumed we were the darlings of the cosmos. Then in the early 1500s, Polish astronomer Nicolaus Copernicus proposed a radical, although not entirely new, idea: not we but the Sun was at the center. For over a half century after his death, there was no credible evidence to support his theory -- until in 1610 when Galileo turned the newly invented telescope to the heavens. Among other things, he discovered that Venus went through phases. Unlike the phases of our Moon, which does orbit Earth, Galileo deduced that Venus' phases could only be explained if Venus orbited the Sun rather than Earth. And if Venus orbits the Sun, then probably we do too. So the lovely "evening star," upon which countless wishes have been made, helped bring about one of history's most profound discoveries, and furthered our understanding of our place in the universe.
- Astro Quote: "Star light, star bright, first star I see tonight. I wish I may, I wish I might, have the wish I wish tonight." (unknown)
Aug. 03, 2002
Perseid Meteor ShowerThe year's best-known and usually best meteor shower, the Perseids, should be at its best the night of Aug. 11. We won't have Moon interference this year, so let's hope for clear skies. The Perseid shower actually spans a period of more than a month -- July 17 through August 24 -- so it's not too early to watch for increased meteor activity. The shower is predicted to peak Aug. 12 during the day, but since meteors are rarely visible in daylight, the night of Aug. 11 will be prime viewing time. Start watching after the Moon sets around 10:30 p.m., but expect the best show between midnight and dawn when our part of Earth most directly faces oncoming meteors. The Perseids occurs this time each year when Earth passes through the orbital path of Comet Swift-Tuttle. Traveling in a highly elliptical orbit, the comet spends most of its life far from the Sun, in the deep-freeze of interplanetary space. During its periodic, brief pass near the Sun, its outer layer is melted and tiny fragments of icy, dust and rocky material are ejected and scattered along the comet's path. It is these cometary fragments through which Earth passes each July and August. As they burn in Earth's atmosphere, they produce the fiery meteors (also known as "shooting stars") we see streaking across our sky. The constellation Perseus, from which the Perseids appear to radiate and from which they get their name, rises around midnight in the northeast. So that's a good general direction to face. Watching for meteors requires no special equipment although a reclining lawn chair is nice. The more important factor is viewing location. While some meteors can be seen even from within light-polluted cities, far more will be visible under dark skies. So if you're an urbanite, the night of Aug. 11 would be a good time to go visit a rural friend who stays up late.
July 20, 2002
Sagittarius' Tea PartyYou're probably familiar with the Trojan Horse story in which the Greeks used a gift horse to entice the city of Troy to lower its defenses, making it vulnerable to a sneak attack. Well, we have a similar story in the summer night sky. Here the trickster is Sagittarius the Archer who disguises himself as a cosmic teapot. In an attempt to entice his neighbors, Scorpius the Scorpion and Lupus the Wolf, into his trap, he invites them over for a cup of tea. The presence of nearby Corona Australis (Southern Crown) suggests this is a territorial fracas to determine who rules this area of the sky. The drama occurs far to the south, and its players are visible in the early evening only during the summer. Sagittarius really does look more like a teapot than a battle-ready archer. Composed of 8 stars 15 degrees wide and 10 degrees high, the teapot is now 20 degrees above the southeastern horizon about 10 p.m. (The width of your fist held at arm's length is 10 degrees.) Unlike unlike most constellations which don't look like what they're called, Scorpius really does resemble a scorpion. With the bright reddish star, Antares, at its head, a dozen or so fainter stars form the scorpion's long, fishhook-shaped body extending to the lower left. Scorpius can now be seen stretching 15 to 40 degrees above the southern horizon. Lupus is to Scorpius' lower right, and Corona Australis is below the teapot, but both are difficult to locate without help. The center of our Milky Way galaxy, harboring a supermassive black hole, lies 30,000 light years behind the heart of this region, near the Sagittarius-Scorpius border. When viewed beyond city lights, this especially rich part of the Milky Way looks like steam rising from the spout at the right end of the teapot. Although intervening stars, cosmic dust and gasses make it impossible to actually see the galaxy's center, the entire area is rich with deep sky objects visible under dark skies. With the ecliptic passing through this area, it is regularly visited by the planets and Moon. Indeed, for the next few nights the bright Moon will interfere with seeing the constellations. They'll be easier to find after Wednesday's full Moon. And back to our story. It ends like another classic -- the one about the lady or the tiger. We are left wondering: will the scorpion and wolf be deceived by Sagittarius' disguise, or have they also heard the story of the Trojan Horse?
- Astro Milestones: Today is the 33rd anniversary of the historic 1969 lunar landing when Astronauts Neal Armstrong and Buzz Aldrin became the first humans to set foot on the Moon.
July 6, 2002
Listening to the SkyThe University of Texas' McDonald Observatory located near Ft. Davis in far west Texas is one of the world's important sites for astronomical research. And with its recently expanded Visitors Center and public star parties, it is also becoming an increasingly popular tourist attraction. Less well-known, however, is an even larger telescope situated just below McDonald. While the giant scopes of McDonald look into the night sky, their huge neighbor "listens" -- night and day. It is a radio telescope, part of the continent-wide system called the Very Large Baseline Array. The VLBA consists of ten 82-foot-wide radio telescopes stretching from Hawaii in the Pacific to the Caribbean's Virgin Islands. When data from these scopes are combined in Socorro, NM, it's like having one 5,000-mile-wide radio telescope. With telescopes, radio as well as visual, diameter is all- important -- the wider the receiving surface, the greater the resolution of the image. According to the National Radio Astronomy Observatory, which operates the system, if radio data from the VLBA could be seen by our eyes, the detail would be like reading a Los Angles newspaper while looking through a telescope in New York. Thus, the VLBA is able to "see" with far greater detail than any Earth- or spaced-based optical telescope. Each of the radio telescopes, including the one in Texas, is mammoth. Although fully steerable like optical scopes -- it can be pointed anywhere in the sky -- each weighs 240 tons and when aimed straight up is nearly as tall as a 10-story building. So what can be learned by "listening" to the sky? According to the NRAO, "The VLBA has shown important new details about how stars are formed and how they age, about exploding stars, about galaxies that harbor supermassive black holes at their cores, and about Gamma-Ray Bursters, the most powerful explosions since the Big Bang." And closer to home, it is "also used to precisely measure the location...of each of its observing stations...allowing geologists to study the motion of Earth's continental plates...knowledge that contributes to our understanding of earthquakes and volcanoes." So there's far more in Texas' lovely Davis Mountains than first meets the eyes -- or ears.
June 22, 2002
Year's Midpoint and Earth at AphelionEach year in early July we pass two interesting but generally unnoticed milestones: the year reaches its midpoint and Earth reaches aphelion.
July 2 at 1 p.m. local daylight time, this year will be exactly half over -- 182 1/2 days down, 182 1/2 days to go in this 365-day year. (In April we set our clocks forward 1 hour, so 1 p.m. daylight time is 12 noon standard time.) During leap years, which have an extra day in February, the midpoint is July 2 at 1 a.m. -- 183 days into a 366-day year.
Can you believe 2002 is half gone? Since many use New Year's Day to make resolutions and set goals, the year's midpoint is a good time for a progress check. How are you doing on your resolutions? Have you accomplished half of your goals yet? Have you lived life as fully as you would wish? Have you spent as much time with friends and loved ones as you would like? Perhaps July 2 would be a good time, if needed, to re-affirm your commitment to your resolutions and goals for 2002.
The other milestone, Earth reaching aphelion, actually has less significance than one might initially think. Like all orbiting bodies, Earth's path around the Sun is not a perfect circle but a slightly oval-shaped circle called an ellipse. Thus, there is one point each year when Earth is closest to the Sun, called perihelion, which occurs in early January. There is another point at which it is farthest away, called aphelion, which occurs in early July -- this year, July 5.
At first thought, it might seem that Earth's distance from the Sun produces our seasons -- that we have hot summers when the Sun is nearest, and cold winters when it's farthest away. But we can quickly discard that idea when we realize that aphelion occurs in the heat of our summer. Further, we can remember that summers and winters are reversed at the Earth's northern and southern hemisphere -- while we're now having summer, our "down under" neighbors are having winter. Actually, seasons are a result of the Earth's tilt on its axis, but that's a topic for another column.
The difference in our distances from the Sun really doesn't vary all that much. We are now about 94 million miles from the Sun, only 3 million miles farther than we were in January -- just over 3 percent more, and not enough to have a noticeable effect on our temperature. But it's still fun to think about.
June 8, 2002
Partial Eclipse of the SunThere will be a late afternoon annular eclipse of the Sun June 10. From the U.S. it will be partial only, and the further west one is, the better. From most of Texas, the eclipse begins about an hour before sunset and reaches maximum (with the Sun about half covered) as the Sun begins to slip below the horizon. Solar eclipses occur when the new Moon passes precisely in front of and covers all or part of the Sun. By coincidence, the Sun and Moon, as viewed from Earth, appear almost exactly the same size. Although the Sun is about 400 times larger than the Moon, it is also about 400 times further away. The "almost" here is important. Rather than being a perfect circle, the Moon's orbit around Earth is a somewhat elongated circle called an ellipse. So at times the Moon is nearer Earth and actually appears a bit larger; at other times it's further away and looks smaller. (Earth's orbit around the Sun is also elliptical but this is much less of a factor in eclipses.) When a solar eclipse occurs with the Moon is nearer and larger-appearing, the Moon is big enough to temporarily cover the entire Sun. People at those locations on Earth where the Moon-Sun alignment is exact see a total eclipse of the Sun. But when an eclipse occurs with the Moon farther away and appearing smaller, the Moon isn't big enough to hide the whole Sun. Called an annular eclipse, this is the kind happening this time. From those places where the alignment is exact, the Moon will appear to cover the middle of the Sun, leaving a small "ring of fire" around the Moon's silhouette. Unfortunately, the "ring of fire" for this annular eclipse will be visible only from the Pacific Ocean. The western half of the U.S., including Texas, can, however, see a partial eclipse where the Moon covers part of the Sun. And even this should still be an interesting event to witness. An important note of caution: Light from the Sun can cause permanent damage your eyes, so DO NOT attempt to view this without a proper solar filter. Sun glasses -- even several pairs stacked together -- do not protect your eyes. It is safe to use #14 welder's glass available from welding supply stores. For safe indirect viewing, a pinhole projector is fun. A small pinhole in a piece of cardboard or aluminum foil will project a tiny image of the Sun onto a piece of white paper held behind the pinhole. But DO NOT look THROUGH the pinhole -- look only at the projected image.
May 25, 2002
Venus and Jupiter Finally MeetIf you've been watching the planets' evening shows over the past few weeks, then you know Venus is the biggest flirt in the night sky. And why not? The goddess of love and beauty is the only female among the planetary deities, making her the queen of the planets. Mars, god of war, Jupiter, king of the gods, and Saturn, father of Jupiter, have all been in the evening sky since last year. Mercury made a brief evening appearance in late April and early May. Since the brilliant Venus burst on the scene in February, assuming her 2002 stint as the "evening star," she has been climbing gradually higher above the western horizon each night. And while doing so, she has been toying with one planetary god after another. The busy queen has even found time for her standing dates with the crescent Moon as he passes through her neighborhood each month. Late last month she spent time with Mercury, the fleet-footed messenger of the gods, low in the west. But he must not have impressed her as she never let him get closer than 6 degrees. (The width of your fist held at arm's length is 10 degrees.)
She then set her sights on Saturn and Mars further up. On May 6 she came within a tantalizing 3 degrees of Saturn but quickly slipped right past him as she was hot on the trail of the feisty Mars. When she finally caught up to the red planet, the twosome spent 4 nights within 1 degree of each other -- less than the width of your index finger held at arm's length.But being an eternal sky goddess, Venus is destined to never stay with any one god too long. After leaving Mars, the queen began her pursuit of King Jupiter. That rendezvous takes place next week when for several nights the two brightest planets will be dancing low in the west. At their closest on June 3, Venus will be 1 1/2 degrees (3 moon-widths) to Jupiter's upper right. Look for them 20 degrees above the western horizon 30-45 minutes after sunset. Don't wait too long as they set a couple of hours after the Sun. This will be a sight you won't want to miss, so here's hoping for clear skies.
- Astro Quote: "On the twilight evening of June 15, 1852, Thoreau wrote: `It is candle-light. The fishes leap. The meadows sparkle with the coppery light of fireflies. The evening star, multiplied by undulating water, is like bright sparks of fire continually ascending.' This evening star, subject of so many great poems, was in fact Venus that night." (David H. Levy, More Things in Heaven and Earth, 1997, p. 95)
May 11, 2002
Spring Sky: Cosmic BaseballBatter up! Baseball season is now underway, so it must be time for cosmic baseball. Just as the Earthly sport's season lasts from spring through fall, there's a cosmic field among the evening stars visible from late spring through early fall. Four stars, each from a different constellation, form a large pattern known informally as the Diamond of Virgo. They also make a great baseball diamond, and by coincidence, each star's magnitude number matches its corresponding base. (The magnitude scale is a system astronomers use for measuring the brightness of stars. It's a "backward" scale where the brighter the star, the lower the number -- a 1st magnitude star is brighter than a 2nd magnitude star, and so on.) For the most important base, home plate, we use one of the night sky's brightest stars, Arcturus at magnitude 0. First base is Virgo's 1st magnitude star, Spica. For second base we have Leo's Denebola at 2nd magnitude, and the 3rd magnitude Cor Caroli in Canes Venatici is third base. As baseball fans know, we need a shortstop between second and third base, and we've got a great one -- the faint but lovely constellation, Coma Berenices. Rounding out the infield, a 3rd magnitude star (with no popular name) is the pitcher's mound. Several constellations make up our outfield. Beyond second base, the large Leo the Lion is center field. For left field, we have Leo's little brother, Leo Minor. Three faint constellations -- Corvus the Crow, Crater the Cup and Sextans the Sextant -- make up right field. And finally, the sky's longest constellation, Hydra the Water Snake, is the right field fence. To locate this cosmic baseball diamond in the night sky, we start with the Big Dipper now high in the north. The arc of its handle "arcs to Arcturus," the brightest star high in the east 30 degrees from the handle's last star. (The width of your fist held at arm's length is 10 degrees.) The arc then continues another 33 degrees to Spica, the brightest star in the southeast. Denebola, the not-as-bright tail star of Leo, is 35 degrees to Spica's upper right in the south. Completing the diamond is even fainter Cor Caroli found 28 degrees to the upper left of Denebola. (Cor Caroli is the brightest star 15 degrees beneath the Big Dipper's handle.) Spotting the large but faint star cluster, Coma Berenices between Denebola and Cor Caroli, requires dark skies or binoculars. Of the outfield constellations, only Leo is bright and easy to find. The others are faint and unspectacular. So there we have it -- a cosmic baseball field for our favorite summer pastime. Now if we can get the Astros and Rangers to winning here in Texas!
April 27, 2002
Continuing Dance of the PlanetsHopefully, between clouds, you've been watching the early evening dance of the planets the past couple of weeks. If not, it's not too late. Soon after dark, the western sky comes alive with many bright star-like objects, all of which aren't stars. The five brightest planets have been presenting a striking alignment stretching from Mercury near the horizon to Jupiter high in the west with Venus, Mars and Saturn in between. And their dance continues with a lot of changing partners coming up. Tonight, Mercury and Venus are paired just above the horizon with Venus the brighter and higher of the two. Saturn and Mars are a little higher with brighter Saturn to the upper left. Jupiter, the brightest object high in the west, is currently without a planetary partner. Monday and Tuesday, Mercury passes left of the Pleiades star cluster, a sight that will look best in binoculars around 9 p.m. Mercury is climbing higher each night, reaching its farthest point from the setting Sun the first week in May. It pulls within 6 degrees of Venus Tuesday, but the flirtatious Venus lets him get no closer. (The width of your fist held at arm's length is 10 degrees.) The evenings of Thursday, Friday and May 4, Mars waltzes within 2 degrees (the width 4 full Moons) of Saturn. Then things really get interesting the next week. After dumping Mercury, the fickle Venus toys with Saturn while really chasing Mars. May 5 finds the three in a triangle less than 3 degrees from the other. All will easily fit within the same binocular field of view. Venus passes nearest Saturn May 6 while in hot pursuit of Mars. May 8 finds Mars dancing with a background star cluster with Venus a mere 1 degree below. The cluster, called NGC 1746, won't be visible to the naked eyes, but should show in binoculars or a small telescope. By the next night, it's Venus dancing with the cluster with Mars 1/2 degree above (the width of a full Moon). Now if you're thinking Venus is finally about to meet and hang around with Mars, you just don't know Venus. They have a brief fling, getting closest May 10, but then the heavenly queen starts drifting away from the jilted Mars. It seems she really has her eyes on King Jupiter, but that's for a later column.
- Astro Quote: "The morning star comes out at night / Without the dark there is no light / If nothing's wrong, then nothing's right / So let it be a dance." (Ric Masten, from the poem/song "Let It Be a Dance")
- StarDate: In response to a request from a "Loyal Reader," here are airtimes for McDonald Observatory's daily "StarDate" astronomy program on three area public radio stations: KWBU-FM 103.3 (Waco) Mon.-Fri. 5:49 a.m., 3:58 p.m.; KNCT-FM 91.3 (Killeen) Mon.-Fri. 5:57 a.m., 4:57 p.m., Sat.-Sun. 8:20 a.m.; KUT-FM 90.5 (Austin) Mon.-Fri. 9:04 a.m., Sat.-Sun. 8:04 a.m.
April 13, 2002
Dazzling Planetary Alignment
Over the next few weeks we'll be treated to one of the most dazzling planetary alignments in years when all five naked-eye planets align in the evening sky. Making the show even more spectacular, the Moon passes among them during the next few days.Venus, Mars, Saturn and Jupiter are now visible soon after sunset. The Moon joins the show tomorrow evening as a thin crescent to Venus' upper left low in the west. Monday night the Moon will be to the lower left of Mars, Tuesday night just above Saturn, and then near Jupiter Thursday night. The highlight of the show, however, occurs Wednesday evening with a sight you won't soon forget. Timing is everything in seeing this event, so begin looking 30 minutes after sunset (8:30 p.m.), even though it won't yet be completely dark. Mercury will be 4 degrees above the western horizon, Venus 15 degrees, Mars 27 degrees, Saturn 35 degrees, the Moon 50 degrees, and Jupiter 61 degrees -- aligned in nearly equal intervals. (The width of your fist held at arm's length is 10 degrees.) While Wednesday's 6-object alignment will be the show stopper, the performance goes on several more weeks. As the planets move through the evening sky at different speeds, there will be some great planetary conjunctions (close pairings and groupings) which we'll talk about in upcoming columns. But alas, the show won't last forever. Mars, which has been in the evening sky for a year, will sink into the Sun by early summer. Jupiter and Saturn, which joined Mars last fall, will also disappear soon -- Saturn in June, Jupiter in July. Venus, which recently became the brilliant "evening star," will get higher through mid summer before retreating into the Sun in early fall. The elusive Mercury, just starting to show low in the west soon after sunset, will be at its highest in May. Sometimes called the classic planets, humans have been watching these five beauties since prehistoric times. The other three (besides Earth) were discovered "recently" -- Uranus in 1781, Neptune in 1846, and Pluto in 1930. And a final note for the purists: yes, Uranus is technically a naked-eye planet -- but just barely so and only under very dark skies. It's not usually seen without optical aids.
- Morning Comet: Comet Ikeya-Zhang, discovered February 1, has recently moved from the evening to the morning sky. Now visible in Cassiopeia, it is heading toward Cepheus and Draco. Although visible to naked eyes under dark skies, it shows better in binoculars.
- Star Party: Today (April 13) is the annual Lake Whitney State Park Spring Star Party. Daytime activities include solar viewing, telescope-making demonstrations and videos. The evening will feature slide programs and night-sky viewing. Other than nominal park entry fees, the event free and open to the public. For more information, call the park at 254-694-3793.
March 30, 2002
McDonald Observatory: Texas' Astronomical Jewel
Some 60 years ago, Texas became an important player in the field of astronomy, and it all began with the death of a frugal, eccentric banker from the small town of Paris, Texas.William J. McDonald died in 1926 at age 81, and having never married, he left no widow and no children. What he did leave, however, was his entire estate to the University of Texas for the construction of an astronomical observatory. After resolving legal problems with McDonald's relatives who contested his will, UT had another problem: it had no astronomy department. So it formed a partnership with the University of Chicago's Department of Astronomy. Chicago owned the renown Yerkes Observatory in Wisconsin, but Yerkes was a victim of bitterly cold winters, many cloudy nights, and increasing light pollution from encroaching urbanization. So the Chicago astronomers, and Otto Struve in particular, were eager to work with UT in the construction and operation of a world class observatory in "wild west" Texas. Struve personally selected the site -- a perch high atop the 6,800-foot Mt. Locke in the Davis Mountains of west Texas, near the small, historic town of Ft. Davis. Far from big-city lights, this location also had more cloudless nights per year as well as a more comfortable climate. Struve also helped design what would be, when completed in 1939, the world's second largest telescope -- an 82-inch diameter cassegrain reflector. For 30 years, this telescope (now named the Otto Struve Telescope in his honor) WAS McDonald Observatory. Important discoveries made with the Struve include Gerald Kuiper's 1948 discovery of Uranus' moon Miranda. Today McDonald Observatory is far more with the Struve being only its third largest telescope. In 1969, the 107-inch diameter Harlan Smith Telescope was completed just in time to help NASA map and study the Moon for the Apollo Moon-landing missions and Mars for the Viking landers. The newest member of the McDonald family, completed in 1997, is the giant Hobby-Eberly Telescope, one of the world's largest at 9.2 meters (30-feet) in diameter. The story of McDonald Observatory, Texas' astronomical jewel, is too much for one column so we'll visit it again in future columns. In the meantime you might want to read Mark G. Mitchell's Seeing Stars - The McDonald Observatory: Its Science and Astronomers (Eakin Press, Austin, TX, 1997) and visit the McDonald Observatory Website at mcdonaldobservatory.org.
- Star Party: The annual Lake Whitney State Park Star Party will be held April 13. For more information contact organizer Thomas Williamson (817-656-0901 or email@example.com) or see the Website at whitney-astro.com.
- Time Change: Saturday evening, April 6, before retiring, set your clocks and watches up one hour ("spring ahead") to Daylight time. And remember the old Stargazer legend. There's one magic hour each year when you are free to do anything your heart desires with no adverse consequences, and that hour occurs from 2 to 3 a.m. the first Sunday in April. Enjoy.
March 16, 2002
Central Texas Observatory Update
It's time for an update on the astronomical observatory and education center being build in our area by the Central Texas Astronomical Society.In 2000, Charles and Dorothy Turner donated 5 acres of land to CTAS for the establishment of the Turner Research Station. Situated 10 miles southwest of Clifton, TX, just inside Coryell County on Hwy. 182, the site provides some of the darkest night skies in this part of the state -- ideal for general stargazing as well as more serious astronomical observations. Last year Paul J. Meyer gave $375,000 to CTAS for the construction of the Paul J. Meyer Observatory on that site. Since last summer several components of the project have been set in motion. Through a combination of hired and volunteered services, the land has been surveyed and fenced, a culvert, driveway and gate installed, and the main parking area, roads and observing field have been cleared and graded. A contract was signed with Astronomical Consultants & Equipment of Tucson, AZ, in November 2001 for the construction of a 24-inch research-grade, remote-controlled telescope for the observatory. Last fall ACE president Dr. Peter Mack came to Waco to meet with CTAS officials and inspect the site. The telescope is scheduled for completion and delivery in Nov. 2002. In January, an order was placed with Ash-Dome of Plainfield, IL, for a dome to house the telescope atop the Meyer Observatory. The 22-foot diameter dome is to be delivered in August. Construction of the observatory building will start this spring, and, according to CTAS president John McAnally, the Paul J. Meyer Observatory should open in early 2003. As other donors come forth, future plans for the Turner Research station include an education center with a classroom and additional smaller telescopes, a visitor center, an amphitheater and nature trails. For more information, including how to join CTAS, visit the CTAS Website at www.centexastronomy.org or call Johnny Barton at (254) 881-2125.
March 2, 2002
The Great Winter Arc
In terms of bright stars, the evening sky of late winter and early spring is unrivaled by that of any other season. Of the 21 brightest stars, called 1st-magnitude, only 16 are ever visible from Central Texas, the others being too far south to rise above our horizon. Now, and for the next few weeks, nine of these stars can be seen in the early evening.One signature configuration of the winter sky is the Great Winter Arc with four 1st-magnitude stars: Sirius, Procyon, Pollux and Capella. Shaped like a huge "C," the arc starts at Sirius, and extends high overhead. At 8 p.m., Sirius, the brightest star in the night sky, is nearly half way up from the horizon in the south. The arc then proceeds to Procyon, 25 degrees to Sirius' upper left. (The width of your fist held at arm's length is 10 degrees.) Up another 25 degrees are Pollux and Castor, the Gemini twins. Curving back to the right 30 degrees, the arc ends at Capella. Within the arc are the constellations of Orion, the Hunter, and Taurus, the Bull. Orion is home to two 1st-magnitude stars, Betelgeuse and Rigel, while Taurus features Aldebaran, the "red eye of the bull." Two 1st-magnitude stars not in the winter arc area are Leo's Regulus in the east, and Canopus, the second brightest star, seen just a few degrees above the southern horizon. And if all this isn't enough to get you out under the stars, four planets are now visible. Jupiter, brighter than any star, is high overhead. Saturn is near and a bit brighter than Aldebaran. Mars is lower in the west. Venus, just beginning her stint as the "evening star," is now very low in the west just after sunset. She'll get better each night and is setting the stage for some interesting planetary alignments and conjunctions in the late spring, so stay tuned.
- Astro Milestones: March 13 is the 221st anniversary of the 1781 discovery from Bath, England of the planet Uranus by English astronomer William Herschel (1738-1822). March 14 is the 123rd anniversary of the birth of German-American cosmologist Albert Einstein (1879-1955).
- Astro Quote: "The most beautiful thing we can experience is the mysterious. It is the source of all art and science." (Albert Einstein, 1949)
February 16, 2002
Moon Occults Saturn
All the planets orbit the Sun on about the same plane. And our Moon orbits Earth on this same plane. The visual effect is that the Sun, Moon and planets all seem to travel nearly the same route through our sky, a pathway astronomers call the ecliptic.
Although they travel the same path, they move at different speeds, so from our perspective they are always passing one another. If they all traveled on exactly the same plane, one would always pass in front of the other every time they passed. This would, for example, produce a solar eclipse with every new Moon and a lunar eclipse with every full Moon.
But they don't, so the Sun, Moon and planets pass each other at varying distances -- sometimes close, more often at some distance. Occasionally two or more bright planets appear quite close, creating a planetary conjunction, one of the most striking of the night sky events.
The Moon, the fastest moving night sky object, passes the Sun and planets every month. Usually it passes some distance above or below and is not of much note. But sometimes it happens to pass extremely close to a planet in the early evening when we are most apt to be looking. An example of this will occur Friday night when the Moon passes very near Jupiter (see below).
Much less often, the Moon actually occults (passes in front of) a planet -- and we happen to have an occultation coming up Wednesday afternoon when the Moon temporarily hides Saturn. The ringed planet will disappear behind the upper left, shadowed side of the 1st quarter Moon about 5:27 p.m. (before sunset), and reappear from the right, illuminated side about 6:57 p.m.
Because of daylight during the disappearance, and glare of the Moon during reappearance, a telescope will be needed to see this event. Even a small amateur scope should suffice, but if you don't have a scope, you're welcome to come watch it with me in my front yard (see address below).
- Astro Milestones: On Feb. 18, 1930, Clyde Tombaugh discovered the planet Pluto on photographic plates taken from Lowell Observatory near Flagstaff, Arizona. Feb. 19 is the 529th anniversary of the birth of Nicolaus Copernicus (1473-1543), Polish astronomer whose thesis that the Sun rather than the Earth is at the center of the universe revolutionized scientific and theological thinking in the western world.
February 02, 2002
Preview of 2002
Most casual stargazers are fascinated by four types of events: planetary conjunctions, eclipses, meteor showers and comets, So let's look at the prospects for each during 2002.
The year's best shows are likely to be planetary. Mercury will make it's prime evening appearance in April. Venus will be the "evening star" in the west during the spring and summer, then become the "morning star" in the east in late fall. Mars, Jupiter and Saturn will remain in the evening sky through the spring, then move into the morning sky in late summer.
May and early June will feature some dazzling multi-planet alignments as well as several conjunctions when two or more planets pass near each other or the Moon. And throughout the year there will be several pairings of brilliant Venus with a slender crescent Moon -- always a beautiful sight.
As for eclipses, the U.S. will see a partial eclipse of the Sun late in the afternoon on June 10, and a faintly visible eclipse of the Moon in November.
Meteor showers occur on about the same date each year, but their degree of intensity varies -- some years rich, some years sparse. This factor is difficult to predict, but easy to predict is the Moon's phase during shower's peak. When the Moon is up its glare washes out all but the brightest meteors, making meteor watching most unsatisfying. Unfortunately, the Moon interferes with most of this year's major showers including November's Leonids which have been spectacular in recent years. But fortunately, two of the usually richer showers will be notable exceptions: the Perseids in August and the Geminids in December.
No periodic naked-eye comets are due this year, however there's always the possibility of new comet discoveries (like Hyakutake in 1996) -- so here's hoping.
So, while nothing spectacular is anticipated for 2002, there should still be plenty to see. Some comments on things which affect our seeing these events is in order. We're always at the mercy of the weather as clouds are beyond our control. A factor we can partially control, however, is light pollution. Those of us who live in cities can see much more by driving a few miles into the country. Finally, and most importantly, only you can decide whether to go outside and let Mother Nature enrich your soul with her beautiful night sky.
- Astro Milestones: Tomorrow is the 96th anniversary of the birth of American astronomer Clyde Tombaugh (1906-97), discoverer of the planet Pluto in 1930. Feb. 15 is the 438th anniversary of the birth of Italian astronomer Galileo Galilei (1564-1642).
- Astro Quote: "The stars are a free show; it doesn't cost anything to use your eyes." (George Orwell, Down and Out in Paris and London, 1933)
January 19, 2002
Moon Tour of 3 Planets
When viewed without optical assistance, planets and stars look rather alike in the night sky. So it's not surprising that most folks have difficulty telling them apart.
In reality, they are quite different kinds of objects. Planets are smaller, most being much smaller than most stars. Stars generate and emit light whereas planets merely reflect sunlight. Our Sun's planets are vastly nearer to us than the night sky stars. Yet when we view them with our naked eyes, both look like little more than points of light.
An old saying -- "Stars twinkle, planets don't" -- is helpful, yet not fail-safe. Under some sky conditions, the twinkling of stars is subtle and difficult to notice. And at times, the light from planets is unstable and appears to twinkle.
Over the next week, the Moon can be a handy guide for identifying three planets now prominent in the evening sky: Mars, Saturn and Jupiter. Unfortunately, the Moon is now waxing -- becoming more illuminated and brighter each night, and making it increasingly difficult to see other night sky objects. But fortunately, these three planets are all rather bright.
Tonight, Mars, the red planet, will be 11 degrees to the lower right of the Moon. (The width of your fist held at arm's length is 10 degrees.) Now passing through the constellation Pisces which has no bright stars, Mars is easy to identify with no stellar competition.
By mid-week, the Moon will visit Saturn. The ringed planet will be 7 degrees to the Moon's left Wednesday evening, then 6 degrees to its right Thursday. Saturn is now in Taurus near it's brightest star, Aldebaran. The slightly brighter and creamy- colored Saturn is 4 degrees to the upper left of the reddish- colored star.
By week's end, the Moon will guide you to the final planet, Jupiter. The king of the planets will be 9 degrees to the Moon's lower left Friday evening, then 5 degrees to it's upper right Jan. 26. Now in Gemini, Jupiter easily outshines all neighboring stars, and indeed, everything except the Moon.
Hopefully clear skies will allow you to take in each night of the Moon's free planetary tour.
- Anniversary: With this column, Stargazer begins its 13th year. Your readership is appreciated as are your calls, emails and correspondence.
- Star party tonight: The Central Texas Astronomical Society will have its free annual "Learn To Use Your New Telescope" star party tonight from 6:30 to 8:30 at Hewitt City Park. Society members will be available to provide individual assistance. All are welcome, with or without a telescope.
- Astro Quote: "It would be well perhaps if we were to spend more of our days and nights without any obstruction between us and the celestial bodies." (Henry David Thoreau)
January 5, 2002
Upcoming Stargazing Opportunities
From what I've heard, Santa delivered some new telescopes and binoculars this Christmas. While that can be exciting, it can also be a source of frustration. Learning to use a telescope (or even binoculars) can be more challenging than you might think. Whether or not you were one of the lucky ones, you might be interested in some upcoming opportunities for new stargazers.
The Central Texas Astronomical Society will be conducting two events geared especially, but not only, for new telescope and binocular owners. The first is an indoor session, "Setting Up Your New Telescope," which will be held Jan. 17 from 6:30-8:30 p.m. at the Waco-McLennan County Library (1717 Austin Ave.). New (or old) owners are invited to bring telescopes and binoculars to receive tips on basic use, as well as specific instruction on their own instrument.
Then Jan. 19 from 6:00-8:30 p.m. CTAS will hold an outdoor "Learn How to Use Your New Telescope" star party at Hewitt City Park. In addition to individual instruction provided by society members. there will also be public viewing opportunities.
Both events are free and open to all, with or without scopes or binoculars. For more information, call Dick Campbell at 857-8310.
Learning to use a telescope or binoculars is just part of becoming a stargazer. One must also know what to look for and how to find it, and that requires at least some familiarity with the night sky. For that, you might consider the Stargazer's five-session "Stars & Constellations of Winter" course to be held January 29, 30, 31, February 4 & 5 from 7:00-8:30 p.m.
The first class, held indoors, covers stargazing basics. The remaining sessions, held under the stars at Camp Fire's Camp Val Verde (between Waco and McGregor), focus on learning the major constellations, stars and naked-eye objects of the season.
The cost is $25 per person with family discounts and scholarships available. Clouded out classes are rescheduled. Call or email the Stargazer for information or to register.
While none of the above events require membership in CTAS, you are welcome to join. The $12 per year dues are a bargain as benefits include receiving society newsletters, participating in CTAS star parties and programs, and access to the Turner Research Station which is expected to open later this year. For membership information, contact Johnny Barton at 881-2125.
- Attention Educators: As an educational service of the Central Texas Astronomical Society, the Stargazer conducts free classroom astronomy programs for area schools. Evening outdoor viewing sessions can also be arranged.