Paul Derrick's Stargazer



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

Stargazer Columns 2008

Dec. 27, 2008: The Stargazer's Crystal Ball
Dec. 13, 2008: Winter Solstice
Nov. 29, 2008: An Evening Rendezvous to Behold
Nov. 15, 2008: Black Holes
Nov. 01, 2008: When Will Humans Return to the Moon, and Beyond?
Oct. 18, 2008: Mayan Astronomy
Oct. 04, 2008: A Fascination for Satellites
Sep. 20, 2008: It's Only a Theory
Sep. 06, 2008: "How powerful is your telescope?"
Aug. 23, 2008: Evening Sky Full of Planets
Aug. 09, 2008: A Collision of Galactic Proportions
Jul. 26, 2008: Starnymph and Songsmith
Jul. 12, 2008 A: Learning the Night Sky Class
Jul. 12, 2008 B: Telling Planets from Stars
Jun. 28, 2008: Evening Rendezvous in the West
Jun. 14, 2008: Tunguska Event
May 31, 2008: Where Are Venus and Mercury?
May 17, 2008: Mars Passes Through the Beehive
May 03, 2008: Phoenix to Look for Martians
Apr. 19, 2008: The Big Dipper As Your Nighttime Guide
Apr. 05, 2008: Cosmic Sizes and Distances
Mar. 22, 2008: Pirates' Eye Patch
Mar. 08, 2008: Why Is Easter So Early This Year?
Feb. 23, 2008: Happy Leap Day
Feb. 09, 2008: Total Eclipse of the Moon
Jan. 26, 2008: The King and Queen Meet in the Morning
Jan. 12, 2008: Looking Forward to 2008

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December 27, 2008
Stargazer #495

The Stargazer's Crystal Ball

Have you ever wondered how the Stargazer predicts astronomical events with such certainty? Does it seem like he has a cosmic crystal ball? Actually what I use is far more reliable than the devices of fortune tellers.

In foretelling night sky events, I rely on smart people who know how to calculate the movements of the Sun, Moon, planets, stars and other heavenly objects we enjoy watching. These experts share their predictions in various formats, several of which I use extensively.

While most astronomical events are as reliable as clockwork--like Moon phases, solar and lunar eclipses, movements of the planets, and the pattern of stars visible on any given night--some are less predictable and are presented as educated guesses--like the intensity of meteor showers, the expected brightness of comets, and the color of a fully eclipsed Moon.

For starters it's hard to beat two monthly magazines: Sky & Telescope ( and Astronomy (, each costing around $40 per year.

Longer-range predictions are found in Guy Ottewell's annual Astronomical Calendar, available for about $30 through Sky & Telescope's website.

And for night-sky simulations there are some amazing computer programs available, Software Bisque's TheSky ( being the one I use regularly. Night sky events vary by time and viewing place so these programs allow users to designate any location by selecting from a list of cities or by entering the latitude and longitude. And they allow the entry of any date and time, usually with a range of hundreds, even thousands, of years into the past or future.

By entering the appropriate data, I can see and even print out a sky map of how the night sky will appear at an upcoming star party. Or in my archaeoastronomy study, I can simulate a long-ago night sky. For example, by entering the latitude and longitude of an ancient Maya capital, and a date they were known to have lived there, I can see the night sky as seen by ancient Mayas to whom the night sky had great importance.

Since there are far more night-sky events than I have space to mention in this column, I'm selective in what I call to your attention. Most folks don't have telescopes, so I focus on naked-eye events, although sometimes I mention things for which binoculars are helpful. And most of us live in light-polluted areas, so I skip objects or events requiring extremely dark skies. For those wanting a more inclusive calendar of events, my Website has a detailed monthly Sky Calendar.

  • Next Two Weeks. Avg. sunrise: 7:29 a.m.; avg. sunset: 5:38 p.m. (exact for Waco,TX)
    * Tonight the Moon is new.
    * Tomorrow 45 minutes after sunset, a thin crescent Moon, Mercury (above the Moon) and Jupiter (above Mercury) are aligned just above the southwestern horizon with Venus well above them.
    * By Dec. 31, Mercury is just to the left of brighter Jupiter, and higher up the crescent Moon is above Venus.
    * The morning of Jan. 3, the Quadrantid meteor shower peaks, and Earth is a perihelion (nearest the Sun) for the year.
    * The Moon is at 1st quarter Jan. 4.

  • Naked-eye Planets. Evening: Brilliant "evening star" Venus dominates the west with Mercury and Jupiter far to the Venus' lower right at dusk. Morning: Saturn is high in the south.

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December 13, 2008
Stargazer #494

Winter Solstice

The winter solstice, the first day of winter and the shortest day and longest night of the year in the Northern Hemisphere, falls on December 21 this year.

Have you ever wondered about the word "solstice?" Literally, it means "the Sun stands still," and it happens twice each year, at winter and summer solstice. Of course, the Sun really doesn't stand still--indeed it doesn't even move as it's apparent daily movement across our sky comes from Earth's rotation on its axis.

What does stand still is the Sun's rising and setting point on the horizon. The Earth's 23 1/2 degree tilt on its axis which produces seasons also causes the Sun to rise and set at a slightly different place on the horizon each day of the year. At the spring equinox the Sun rises exactly due east and sets exactly due west, making day and night each 12 hours in length.

Sunset at different seasons

Each day thereafter it rises slightly north of east and sets slightly north of west. Since the Sun's path across the sky tilts to the south in our hemisphere, the Sun is in the sky slightly longer each day, and days grow increasingly longer than nights until the summer solstice. Then the gradual daily northward movement of the Sun's rising and setting points stops and the Sun "stands still." The day of the summer solstice is the year's longest day with the Sun in the sky longer than any other day--at our latitude about 14 hours.

The Sun then reverses course and begins retracing its steps, rising and setting slightly south of where it rose and set the previous day, making each day slightly shorter. At the fall equinox, when it again rises and sets due east and west, the day and night are again of equal length.

The rising and setting points continue to gradually move southward until the winter solstice when the Sun again "stands still" on the year's shortest day--about 10 hours for us. So next week when the Sun stands still at its southern-most rising and setting points, it will be the shortest day of the year and the beginning of winter, but it also means each day thereafter we can look forward to gradually longer days until the summer solstice.

Knowledge of the movements of the Sun, Moon, planets and stars was important in the lives of the ancients, thus they were quite in tune with rhythms of nature, like the solstices. That we moderns no longer are, I think, is our loss.

  • Next Two Weeks. Avg. sunrise: 7:23 a.m.; avg. sunset: 5:29 p.m. (exact for Waco, TX)
    * Wed. morning (Dec. 17) the Moon is below the star Regulus. * Thurs. morning (Dec. 18) the Moon is to the right of Saturn. * Dec. 19 is Saturnalia, an ancient Roman festival celebrating the god and planet Saturn. * The morning of Dec. 21 the crescent Moon is below the star Spica. * The morning of Dec. 22 the Ursid meteor shower peaks under favorable Moon conditions. * Christmas morning a thin crescent Moon is below the star Antares at dawn.

  • Naked-eye Planets. Evening: "Evening star" Venus is brilliant in the west with Jupiter to Venus' lower right. Morning: Saturn is high in the south.

  • Star Party. The Central Texas Astronomical Society's free monthly star party is Dec. 20 at the Waco Wetlands beginning at 7 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

November 29, 2008
Stargazer #493

An Evening Rendezvous to Behold

In what should be the most beautiful celestial show of the year, the three brightest night-sky objects--brilliant "evening star" Venus, bright Jupiter, and the crescent Moon--will come together low in the southwest at dusk Monday evening (Dec. 1). Below are some things to ponder while enjoying the view.

The three are different types and sizes of objects, yet they share the common attribute that none makes its own light. All reflect sunlight like three huge mirrors in the sky.

The Moon, which orbits Earth each month, is a moon. As an aside, have you ever wondered why our Moon and Sun don't have official names? I have. Virtually all the other dozens of moons in our solar system have names, and likewise with most of the other brightest suns. Yet our Moon and Sun, although often capitalized, are officially nameless. Isn't that a bit like naming all the neighborhood dogs and cats except your own, and then calling yours "the Dog" and "the Cat?" Oh, well.

Venus and Jupiter, large objects which orbit the Sun, are both planets but their compositions are different. Venus, similar to our Earth in size and composition, is a solid terrestrial planet, whereas Jupiter is a giant gas planet some 10 times the diameter of Earth and Venus.

While they all now look close together, they really aren't. The Moon is nearest at a mere 251,000 miles away. Venus is now nearly 94 millions miles distant with Jupiter now at 540 million miles.

And given their differing distances, light from the Moon gets to Earth in 1.3 seconds, light from Venus arrives in 8.4 minutes, and Jupiter's light travels 48 minutes before reaching Earth.

Each has differing degrees of reflectivity. Ironically, the brightest of the three, the Moon, is the least reflective. Of the sunlight falling on the Moon's rocky surface, only 7% is reflected back. It has been said that the Moon is about as reflective as an asphalt parking lot.

Being perpetually enshrouded in clouds, Venus is the most reflective of the planets, turning back 65% of the sunlight that shines on it. And its outer layers being essentially clouds, Jupiter's 52% reflectivity almost matches Venus. In case you're wondering, Earth, 70% covered with water, has a 37% reflectivity.

If the Moon was as reflective as Venus, imagine a full Moon casting nearly 10 times more light than it now does. It would certainly take the romance out of moonlight walks, and there would be little stargazing for much of each month.

  • Next Two Weeks. Avg. sunrise: 7:14 a.m.; avg. sunset: 5:25 p.m. (exact for Waco, TX)
    * Wed. The earliest sunset at latitude 30 degrees N comes Wed. evening.
    * The Moon is at 1st quarter Fri.; and Mars is at conjunction with (passes behind) the Sun, then moves into the morning sky.
    * The Dec. 12 full Moon is called the Long Night Moon and the Moon Before 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.)Evening: Venus and Jupiter dominate the west with Venus climbing slightly higher each night as Jupiter sinks toward the setting Sun. Morning: Saturn is well up in the east southeast.

November 15, 2008
Stargazer #492

Black Holes

Judging by questions at my presentations, folks seem more fascinated by black holes than anything else in the cosmos. Indeed, black holes are so exotic, so at odds with common sense, that our minds have difficulty grasping them.

Black holes are invisible, and as I wrote in 1993, "There is no direct proof of the existence of black holes, but there is growing indirect evidence. An increasing number of discoveries and observations are consistent with, and can be explained by, black hole theories." And the case is even stronger today.

To begin understanding black holes, we must recall some high school science about differences between matter and energy. Matter is substance which normally exists as a solid, liquid, or gas; it occupies space and has mass (weight). Energy is a force that has no mass and occupies no space.

Gravity (one of four basic types of force) is the attraction every particle of matter has for every other. The greater the mass, the stronger the gravitational force. Thus, planets exert more gravitational force than people, and stars exert more gravity than planets.

Gravity holds things together. The gravity from Earth's great mass holds our spinning planet together in a tight ball, and keeps us from flying off into outer space.

Stars contain enormous mass, and thus exert crushing amounts of gravity. At their core (center), the pressure is so intense that atoms of hydrogen are crushed, forming atoms of helium--a process called fusion. These nuclear reactions gives off incredible energy, light and heat being the two we are most aware of.

In mature stars (like our Sun), the crushing inward force of gravity is balanced by the outward explosive force of nuclear fusion, and the star exists in a stable balance. But eventually the fusible fuel runs out, nuclear reactions stop, and the star dies. Gravity, no longer balanced by outward explosive forces, causes the remaining core of the star to collapse into a dense ball. When most stars die, they become a white dwarf star-- essentially the corpse of a dead star.

The most massive stars, however, die more dramatically in a supernova explosion. When they collapse their gravity crushes their core into an incomprehensibly small entity called a singularity. (And it is here that our common sense fails us.)

The singularity, consisting of the dead star's crushed remains, still contains all of its mass and gravity. But now the gravity is concentrated into a single point, making the singularity an infinitely dense and small object which has no dimensions and occupies no space.

In the space immediately surrounding the singularity, gravity is so strong that nothing, including light, can escape. Thus a black hole is the infinitely small singularity and the invisible space surrounding it. Does that leave your head spinning? It does mine.

  • Next Two Weeks. Avg. sunrise: 7:02 a.m.; avg. sunset: 5:27 p.m. (exact for Waco, TX).
    * The Leonid meteor shower peaks Mon. morning but the Moon will interfere.
    * The Moon is at 3rd quarter Wed.
    * Fri. morning the Moon is below Saturn in the southeast.
    * The morning of Nov. 24 the crescent Moon is below Spica low in the east southeast.

  • Naked-eye Planets. Evening: Venus is the brilliant "evening star" in the west with bright Jupiter to Venus' upper left. Morning: Saturn is well up in the east southeast.

  • Star Party. The Central Texas Astronomical Society's free monthly star party is Nov. 22 at the Waco Wetlands beginning at 7 p.m., weather permitting. For directions see my Website.

November 1, 2008
Stargazer #491

When Will Humans Return to the Moon, and Beyond?

Each year I present dozens of astronomy programs and classes, and I'm often asked--by adults and youngsters alike--about the future of humans in space. Many know we maintain a small crew in the Earth-orbiting International Space Station, but most (including myself) find that less than satisfying.

What they really want to know is: When will humans return to the Moon, and when will we send humans to Mars and beyond? Here's the official answer. In 2004, the Bush administration set a goal of having humans on the Moon by as early as 2015 and no later than 2020. Unfortunately, it's easy to set goals others will have to achieve. NASA chief Michael Griffin said in 2007, "Space travel is going to be expensive, difficult, and dangerous."

So the question of space exploration really involves at least three more fundamental questions relating to science and technology, affordability, and priorities. Without pretending to be an expert, I'll offer some ideas, and I welcome hearing yours. If we can get a dialogue going, I'll create a page on my Website and post your responses.

First, do we have the science and technology? Probably. In 1957, when Russia launched Sputnik 1 and 2, U.S. rockets were still blowing up on the launch pad. Yet in 1969, a mere 12 years later, U.S. Astronauts Neil Armstrong and Buzz Aldrin walked on the Moon. So surely we could be back on the Moon by 2015.

However, I doubt we will, and maybe not even by 2020--but not for lack of science and technology. Space travel is expensive. Even assuming our current national and world economic crisis won't be prolonged, can we afford to send humans to the Moon and beyond? When we went to the Moon in the 1960s we were also financing the Viet Nam war and the social programs of the Great Society. So can we afford it? Probably--if we have the resolve.

Which, I think, brings us to the fundamental issue: Where does human space exploration rank among our priorities? Many say such an effort will be too expensive for any one nation, and will have to be multinational. Yet the demands on our finite resources are myriad--poverty, disease, famine, energy, wars, deteriorating infrastructures, to name but some on an overwhelming list.

Few would put space exploration as a top priority, yet I wonder if we can afford NOT to keep it prominently on the list. I welcome your ideas.

  • Next Two Weeks. Avg. sunrise: 6:50 a.m.; avg. sunset: 5:34 p.m. (both CST, exact for Waco, TX). Tonight a crescent Moon is to the upper left of Venus. Wed. morning, the Southern Taurid meteor shower peaks with best viewing after the Moon sets at midnight. The Nov. 13 full Moon is called the Frosty Moon and Beaver 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: Venus is the brilliant "evening star" in the west with Jupiter the bright object higher in the southwest. Morning: As dawn breaks Saturn is well up in the east as Mercury hovers near the eastern horizon.

  • Time Change. Before retiring tonight, set your clocks back 1 hour ("fall back") to Standard Time. [Remember the old Stargazer adage: When you set your clocks back, you repeat that hour. Thus whatever you thought you did during the previous hour really didn't happen. So can relive it...and get it right this time, OK?]

October 18, 2008
Stargazer #490

Mayan Astronomy

Dr. John Fox, an anthropologist who lives in Waco, has studied the ancient Mayan civilization for more than 30 years. Last year he made me an offer I couldn't resist.

The Mayas had a keen interest in the night sky, and while Dr. Fox and his colleagues have learned much about Mayan astronomy, he wants to dig deeper. Although an expert on the Mayas, his knowledge of astronomy is limited, so he approached me about working collaboratively with him. He didn't have to ask but once.

Throughout the past year I have been doing crash reading in archaeoastronomy--the study of the astronomy of ancient cultures. At first, it was tempting to think of the ancients as simple-minded primitives--people less sophisticated than modern-day humans and only a notch or so beyond the proverbial cavemen.

But as anthropologist Anthony Aveni reminds us about the ancients: "Their brains were no less advanced than ours, their minds no less inquiring." Thus while living hundreds and even thousands of years ago, the ancients were our intellectual equals--just as smart, just a curious, and seeking answers to the same profound questions of existence we are still asking.

If we seem smarter it's due to our having benefit of humankind's great accumulation of knowledge and our incredibly sophisticated technology. (What more might Galileo have discovered had he had my 8" telescope, or Pythagoras had he had my laptop computer?)

Back to the Mayas. While their Asian ancestors arrived in North America thousands of years ago, the Mayan civilization flourished from about 1000 BCE to the 1520s CE in what today is southern Mexico and Guatemala. What they came to know about the heavens was impressive. They knew more about the workings of the night sky than the average person today knows. As a reasonably sophisticated amateur astronomer, it is humbling to realize these ancients could have taught me many things about astronomy.

Their astronomical achievements were many. They independently discovered the 365-day year. They developed an advanced calendar, accurate to within one day in 500 years, and projected it forward and backward thousands of years. They created tables for predicting solar and lunar eclipses.

Venus had great significance to the Maya, so they knew it well. They understood its 584-day cycle from morning star to evening star and back to morning star, and discerned that its appearances follow a 2,920-day (8 year) cycle during which its night-to-night movement in the sky repeats five distinct and successive patterns (something I had not known).

Next year I hope to accompany Dr. Fox to Guatemala to visit several Mayan archeological sites, paying special attention to the night sky as they might have seen it. We'll see if together we can glean any new insights into Mayan astronomy, and if we do, you'll read about them in future columns.

  • Next Two Weeks. Avg. sunrise: 7:39 a.m.; avg. sunset: 6:46 p.m. (exact for Waco, TX)
    * Mon. night the Orionid meteor shower peaks with best viewing from dark until moonrise at midnight.
    * The Moon is at 3rd quarter Tues.
    * The morning of Oct. 25 the crescent Moon is to the lower right of Saturn low in the east.
    * The evening of Oct. 26 Venus is to the upper right of the star Antares low in the southwest.
    * The Moon is new Oct. 28. Oct. 31, Halloween, is a traditional cross-quarter day celebrating the middle of fall, and a thin crescent Moon is to the upper left of the star Antares with Venus above low in the southwest 45 minutes after sunset.

  • Naked-eye Planets. Evening: Venus is twilight's "evening star" low in the west with Jupiter the brightest object in the southwest. Morning: Saturn rises two hours before sunrise and Mercury climbs to its highest above the rising Sun Oct. 22.

  • Star Party. The Central Texas Astronomical Society's free monthly star party is tonight (October 18) at the Waco Wetlands beginning at 7 p.m., weather permitting. For directions see my Website.

October 4, 2008
Stargazer #489

A Fascination for Satellites

People are fascinated seeing satellites silently gliding across the night sky. We wrote about this last year, but continuing comments and questions compel us to visit the subject again.

While most folks have seen satellites, many weren't sure that's what they were seeing. Much slower than streaking meteors, satellites look more like high-flying airplanes. Indeed, planes and satellites are often confused as they seem to move at the same speed, although they really don't. Planes fly a few hundred miles per hour up to a few miles above Earth, but satellites zip along at some 17,000 mph at altitudes of 200 or more miles.

So how can you tell them apart? If you see red, green, or blinking lights, you're definitely seeing an airplane. (Sometimes it takes binoculars to be sure.) Satellites have no strobe, wing, or other external lights and are seen only when sunlight reflects off their shiny surfaces.

Since they are visible only by reflected sunlight, they can only be seen up to 2-3 hours after dark or before dawn. Deep into the night, they are traveling in the darkness of Earth's shadow.

It's fun being surprised by satellites, but it can be even more fun knowing when and where a satellite will appear, and that information is easily available on the Internet.

My favorite website is Heavens-Above ( It's free but the first time you use it, you'll need to open a user account and indicate from where you'll be watching. (You can designate more than one viewing site.)

If your site is a city, simply select it from the data base; if not, enter your site's latitude and longitude. And if you don't know that, you can get a close-enough estimate from many street maps. Or using Google Earth (which is also free), locate your viewing site, hover the cursor over it, and the site's latitude and longitude are displayed.

Heavens-Above lists visible satellites for a given date range, telling exactly when (date and time) and where (altitude and direction) to look, and how bright each will get. Brightness is given as a magnitude number where the lower the number, the brighter the object. Objects fainter than about magnitude 5 are too faint for the naked eye. The brightest stars are in the magnitude 1 range while Jupiter gets to magnitude -2.5 and brilliant Venus to magnitude -4.7.

The brightest and most dramatic satellites are Iridiums, members of a fleet of some 70 communication satellites, each of which has a flat, door-size, mirror-like antenna which, for a few seconds, can flare to magnitude -8, far brighter even than Venus.

The International Space Station, which has grown so large that amateur telescopes can see its shape, can appear as bright as Venus. Heavens-Above also lists and gives viewing information on other satellites, even large pieces of space debris like shells of rockets used to put satellites into orbit.

To set your watch to the exact time, go to another free Internet service: If you have problems using or interpreting, call or email me. Maybe I can help.

  • Next Two Weeks. Avg. sunrise: 7:29 a.m.; avg. sunset: 7:00 p.m. (exact for Waco, TX)
    * Monday evening the Moon is below Jupiter.
    * The Moon is at 1st quarter Tuesday.
    * Wednesday morning the Draconid (Giacobinid) meteor shower peaks in a dark moonless sky.
    * The Oct. 14 full Moon is called the Hunter's 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: Venus is climbing higher in the twilight as the "evening star" as Jupiter outshines everything in the south southwest.
    Morning: Saturn rises an hour or so before sunrise.

September 20, 2008
Stargazer #488

It's Only a Theory

"It's only a theory." Likely you've heard that before, and understood it to mean that an idea need not be believed or taken seriously. One definition of theory--"an assumption or guess based on limited knowledge or information"--fits this dismissive notion of disbelief.

A theory is simply a proposed explanation for something. We all have theories about a myriad of things, so no wonder it's tempting to regard them lightly.

A theory may or may not be a true or accurate explanation. While the flat Earth theory, held as true for much of history, is now discredited, Newton's theories of gravity have been so validated we now call them laws. The jury is still out on some theories, like those proposing the existence of extraterrestrial life.

So theories may be a dime a dozen, yet in the world of science, theories are everything. According to renown psychologist Kurt Lewin, "There's nothing as practical as a good theory."

What distinguishes scientific from non-scientific theories has do with evidence for scrutinizing them. The word science, meaning "to know," is defined as "the observation, identification, description, experimental investigation, and theoretical explanation of natural phenomena."

That's a mouthful, but in essence it means that the way science knows things is by turning ultimately to empirical evidence--things that can be observed by our senses.

Other ways of knowing--like intuition, authority, and reason--also have a role in science.

Theories and ideas often come from intuition--a hunch or an inspiration. Still, they are not accepted with confidence until and unless they pass the scrutiny of evidence.

And so we don't have to keep rediscovering everything, we pass knowledge from one generation to the next, learning from past authority. But, we've also learned even authorities can be wrong, so we accept only that which has been verified.

Scientists learn by inferring one thing from another. The theory that germs cause some illnesses was inferred before germs were finally observed (verified) in microscopes.

So in science, the bottom line for knowing and judging theories is empirical evidence. Come to think of it, maybe we should apply this to non-scientific theories as well.

Yes, this is an idealized view of science. No human institution is perfect. Even so, we can thank science and its theories for increasing the comfort and longevity of our lives.

  • Next Two Weeks. Avg. sunrise: 7:20 a.m.; avg. sunset: 7:19 p.m. (exact for Waco, TX)
    * Monday is the autumn equinox, the first day of fall when the day and night are of equal length, and the Moon is at 3rd quarter.
    * Wednesday morning the crescent Moon is above the Beehive cluster, and next morning below it.
    * Friday morning the crescent Moon is to the right of the star Regulus low in the east.
    * The morning of Sept. 27, a thin crescent Moon is to the upper right of Saturn low in the east just before dawn.
    * The Moon is new Sept. 29.
    * The early evening of Oct. 1, a crescent Moon is below Venus low in the west with much fainter Mars to their lower right.
    * The evening of Oct. 3, the Moon is to the lower right of Antares.

  • Naked-eye Planets. Evening: Venus is emerging as the "evening star" as Mercury and Mars are sinking into the setting Sun. Bright Jupiter dominates the southern sky. Morning: Saturn is rising low in the east an hour before sunrise.

  • Astro Milestones. On Sept. 23, 1846, Johann Galle & Heimrich d'Arrest discovered the planet Neptune from Germany's Berlin Observatory--a discovery based on the predictions and position-calculations of Urbain Jean Joseph Leverrier of France.

September 6, 2008
Stargazer #487

"How powerful is your telescope?"

At star parties we're often asked: "How powerful is your telescope?" It's a good question, but one we have to answer with a brief explanation about telescopes. And we often start by talking about binoculars which many people have and already know about.

Unlike telescopes, binoculars usually have that information printed on them, expressed as two numbers, like 6x30 or 7x40.

The first number, which gives the instrument's power (also called magnification), tells how much larger and nearer an object will seem to appear. With 7x40 binoculars, for example, 7x means seven-power, thus these binoculars make things look seven times larger and nearer than when viewed with the naked eye.

For most binoculars, the power is fixed and cannot be changed. So, the question about power can be easily answered for binoculars. (Zoom binoculars are an exception.)

The second number, which gives the aperture, tells the size (in millimeters) of the lens at the big end. So the aperture of 7x40 binoculars is 40mm.

The big lens, however, doesn't do the magnifying. It gathers light from the object being viewed and focuses an image of the object on the lens nearest your eyes. That lens, called the eyepiece, does the magnifying.

Now let's look at telescopes. They too have a lens (or mirror) to gather and focus light. (Refracting scopes have a lens at the front end while reflecting scopes have a mirror at the back end--both serving the same purpose.) The diameter of the lens or mirror is the telescope's aperture. So my 8-inch reflecting telescope has an 8-inch mirror to gather and focus light.

And as in binoculars, the light is focused on the eyepiece which magnifies the image. But here's where telescopes have an advantage over binoculars. While binocular eyepieces are fixed, and thus so is their power, telescopes are made so eyepieces, and therefore power, can be easily and quickly changed.

Inserting a more powerful eyepiece yields a higher power than a less powerful eyepiece. For example, I have several eyepieces which give me a choice of powers from 77x to nearly 300x.

So the next time you're at a star party and looking through a telescope, impress your friends by asking: What power are we seeing with this eyepiece?

  • Next Two Weeks. Avg. sunrise: 7:11 a.m.; avg. sunset: 7:37 p.m. (exact for Waco, TX)
    * Tonight (Sept. 6) a half hour after sunset Mercury is below fainter Mars with brilliant Venus to their right, all near the western horizon; and the Moon is two moonwidths below Scorpius' brightest star Antares.
    * Tomorrow (Sept. 7) the Moon is at 1st quarter.
    * Tue. (Sept. 9) evening the Moon is below Jupiter in the south.
    * Early Thurs. (Sept. 11) evening, Venus is less than a moonwidth above much fainter Mars with Mercury to their lower left low in the west.
    * The Sept. 15 full Moon is this year's Harvest Moon, being the full Moon nearest the fall equinox.
    * The evening of Sept. 19, Venus, Mars, Mercury and the star Spica are grouped near the western horizon a half hour after sunset; and later that evening the Moon is three moonwidths below the Pleiades star cluster when they rise around 10:30 p.m.

  • 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, Mercury and Mars are low in the west with Jupiter dominating the south.
    Morning: None.

August 23, 2008
Stargazer #486

Evening Sky Full of Planets

Now is a good time for evening stargazers to view four of the five naked-eye planets.

The easiest is Jupiter which dominates the southern sky in the early evening. Far outshining all stars, Jupiter is the third brightest night sky object behind only the Moon and Venus.

While Jupiter appears as a bright star to the naked eye, most binoculars can reveal its disc-like shape. And if the binoculars are held very steady, up to four of Jupiter's moons can be seen looking like tiny stars in alignment.

On any given night, however, all four may not visible since, as they orbit Jupiter, one or more might be hiding behind or in front of the huge planet. These four largest of Jupiter's many moons--Io, Europa, Ganymede, and Callisto--are called the Galilean Moons in honor of Galileo who discovered them with his new telescope in 1610. They are only slightly larger than our moon, but 1,500 times further away.

Jupiter is now up when the skies darken and doesn't set until the wee hours of morning, so you can watch it all evening. Not so with the other three.

Mars, Venus and Mercury are low in the west at dusk and set before the sky gets completely dark, so don't linger. Start looking 30 minutes after sunset. If you have binoculars, use them, and since the planets are quite low, you'll need a clear view of the western horizon.

Of the three Venus is by far the brightest and easiest to spot. Once you've found Venus, look for fainter Mercury three moonwidths to the lower left. Again, binoculars will help, especially for those (like me) with aging eyes.

Fainter Mars is 10 degrees to their upper left. (Remember, the width of your fist held at arm's length is 10 degrees.)

After you've found them, keep watching them nightly as this is a show that changes each evening.

For the next week or so Venus and Mercury stay in about the same position relative to each other as they gradually approach Mars. The evening of Aug. 31, a thin crescent Moon visits the planetary trio. By Sep. 4, the planets form a nearly equilateral triangle with brilliant Venus to the right, Mercury to the lower left and Mars to the upper left.

In what might be the show's climax, Venus passes less than a moonwidth from Mars Sept. 11. After that, Mercury and Mars sink into the setting Sun and Venus begins asserting herself as the "evening star" where she will remain until well into 2009.

Maybe you've noticed there's been no mention of Saturn. The ringed planet, which has been gracing our evening sky all year, is now hidden in the glare of the Sun. Sep. 3 it reaches conjunction with the Sun--astronomers' way of saying it is exactly on the other side of (behind) the Sun. By October it will have moved into the morning sky.

  • Next Two Weeks. Avg. sunrise: 7:03 a.m.; avg. sunset: 7:55 p.m. (exact for Waco, TX)
    * Tonight the Moon is at 3rd quarter.
    * Thurs. morning the crescent Moon is three moonwidths above the Beehive cluster low in the east shortly before dawn.
    * The Moon is new Aug. 30.
    * The evening of Sep. 2, the crescent Moon is below the star Spica.

  • Star Party. The Central Texas Astronomical Society hosts it free monthly public star party tonight at the Waco Wetlands beginning at 8 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

August 9, 2008
Stargazer #485

A Collision of Galactic Proportions

Recently Eric and his 14-year old son, Tristan, of Johannesburg, South Africa, asked in an email: "What would happen if there was another galaxy headed on a collision course with our galaxy? Would we know about it before we were vaporized?"

The answer contains both bad and good news. The bad news: another galaxy IS on a collision course with our Milky Way galaxy. The even larger Andromeda galaxy is headed our way and the collision will spell the end of our galaxy as we know it.

So where's any good news in that? Fortunately, it will happen 5 billion years down the road. So don't quit your job, drop out of school, or cancel your life insurance.

What's more, while there will no longer be a Milky Way or Andromeda galaxy, neither will be vaporized. According to astronomers Abraham Loeb and T.J. Cox ("Our Galaxy's Date with Destruction," Astronomy, June 2008), the collision will result in the merger of the two galaxies, producing a gigantic galaxy which, combining the names, they dub "Milkomeda." Such mergers, visible in amateur scopes, are common throughout the cosmos.

Although both galaxies contain billions of stars, the likelihood is that few will actually collide with other stars. Galaxies consist mostly of empty space (ignoring the speculative existence of "dark matter" about which astronomers know so little.)

If our Sun was the size of a Ping-Pong ball, the next nearest star would be 625 miles away--that's about four or five Ping-Pong balls within an area size of Texas. So we needn't worry about being vaporized by a stellar crash when the galaxies collide.

Still, we're not completely off the hook. The Milky Way-Andromeda merger will, by coincidence, occur about the time our Sun dies, and when that happens, Earth almost certainly will be vaporized, but again, that's far into the future.

Nearer-term threats are far more likely to come from asteroid and comet impacts. That's why, in my view, our species must allocate more resources to finding and tracking these objects, and devising realistic strategies and means for dealing with them when threatening ones do come our way--and it's just a matter of time.

  • Next Two Weeks. Avg. sunrise: 6:54 a.m.; avg. sunset: 8:11 p.m. (exact for Waco, TX)
    * Wednesday (Aug. 13) evening, low in the west a half hour after sunset, Venus is a moonwidth to the left of Saturn.
    * The evenings of Aug. 14-16, Venus (brightest), Saturn, and Mercury (faintest) are grouped together.
    * The Aug. 16 full Moon, called Green Corn Moon and Grain Moon, features a partial eclipse not visible here.
    * The evening of Aug. 20, Mercury is two moonwidths below Venus.

  • Meteor Shower. The Perseid meteor shower, usually one of the best, peaks Monday night and Tuesday morning, with the best viewing likely from 2 a.m. until dawn, after the moon sets. Perseus, from which Perseids seem to radiate, is 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: Venus, Saturn and Mercury are very low in the west with Mars well to their upper left; Jupiter is the brilliant object in the southeast.
    Morning: There are no morning naked-eye planets visible after Jupiter sets around 4 a.m.

  • Stargazing Class. Paul's free 4-session Learning the Night Sky course is Aug. 18-21, 7:30 - 9:30 p.m. Call or email for more information or to register.

July 26, 2008
Stargazer #484

Starnymph and Songsmith

It's time for another telling of the magical story of Starnymph and Songsmith.

Many eons ago Songsmith, who lived among the animals of the forest, made beautiful songs each day and set them adrift. One night as he was singing under the starry sky, a blindingly bright falling star appeared. When his sight returned, he saw beside him the lovely Starnymph.

She spoke, "For ages I've heard your songs and wanted to come to you, but Starmother said it would be dangerous. She said each day our love for each other would deepen. But since you are a mortal human and will die long before I will, my pain of losing you might be more than my heart can stand."

I said to Starmother, "I'll chance a broken heart – please let me go.”

So Starmother said, “OK, but you can stay only as long as Songsmith makes a new song each day before the midnight hour. Should a day pass that he makes no song, you will have to return to the Starpeople."

And I said, “Oh, Starmother, I know our love will make his music even more beautiful." So Starmother said, "Then, my child, catch a falling star and go to him."

So the years passed, and Starnymph and Songsmith were happier than they'd ever been. Their love deepened as Starmother had said, and each day Songsmith's songs came easily and freely.

But one evening he said, "I am tired. Before making a song, I must rest." And Starnymph said, "I too am tired."

Soon both fell fast asleep. Before they knew it, the midnight hour was upon them and the new day bell began to ring. On the third chime, Starnymph awoke and tried to arouse Songsmith, but he didn't awaken until the twelfth chime. A day had passed that he made no song. Rubbing his eyes, he looked up and saw Starnymph rising into the heavens, her tears falling at his feet. His tears joined hers, forming a reflection pool. Gazing into the pool, he realized that the wonderful years with Starnymph had become decades, and he understood why he was so tired--he had become a very old man.

From his broken heart came one last song. As he finished, life slipped from him, and as it did, a star began to twinkle more brightly. Touched by the love of Starnymph and Songsmith, Starmother had decreed, "Songsmith has earned a place among our Starpeople, and he and Starnymph belong together."

To this day, looking through a telescope at the head star of Cygnus the Swan, a star called Albireo, one sees not one star but two--soft yellow Starnymph and pale blue Songsmith. And listening with the heart, one hears his final song still drifting through the heavens.

  • Next Two Weeks. Avg. sunrise: 6:45 a.m.; avg. sunset: 8:23 p.m. (exact for Waco, TX)
    * Sunday (July 27) morning the Moon is above the Pleiades star cluster, and the Delta Aquarid meteor shower peaks.
    * Friday (Aug. 1) is Lammas, a traditional cross-quarter day celebrating the middle of summer; and Friday's new Moon produces a total eclipse of the Sun that won't be visible from our part of the world.
    * Aug. 2 a half hour after sunset, a thin crescent Moon is to the left of Venus near the western horizon.
    * The evening of Aug. 3 the crescent Moon is below Mars and to the left of Saturn low in the west.
    * The evening of Aug. 6 the Moon is to the lower left of the star Spica.
    * The Moon is at 1st quarter Aug. 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.)
    Evening: Venus is low in the west northwest at dusk, beginning its stint as the "evening star" for the rest of 2008; Mars and Saturn are a little higher in the west, and Jupiter is the brightest object in the southeast.
    Morning: Jupiter sets an hour and a half before sunrise.

  • Stargazing Class. Paul's free 4-session Learning the Night Sky course is Aug. 18-21, 7:30 - 9:30 p.m. Call or email for more information or to register.

Two Stargazers for the price of one this time! ~Paul

July 12, 2008
Stargazer #483A

Learning the Night Sky Class

The Stargazer, in cooperation with the Central Texas Astronomical Society, is offering a free four-session "Learning the Night Sky" course the evenings of Aug. 18-21. Designed for novices, the course is for those who wish to begin learning the basics of stargazing and the constellations of summer.

The Aug. 18 & 19 sessions will be indoor classes from 7:30 - 9:30 p.m. held at the Stargazer's residence at 918 N. 30th St., Waco. These sessions include understanding how the night sky moves, cosmic and angular distances, solar system and deep space objects for observation, and basic stargazing equipment.

The Aug. 20 & 21 sessions will be outdoor under-the-stars classes from 8:30 - 10:00 p.m. to be held at a yet-to-be-determined dark-sky site beyond city lights. (The dates of the outdoor sessions are subject to change if the sky is cloudy.)

In the outdoor sessions participants begin learning the season's major constellations--a goal that can sound daunting. However, the Stargazer has devised a system which makes the task surprisingly do-able. The night sky is partitioned into nine regions, each of which has a story or theme to tie together the constellations within that region. Some stories come from antiquity while others are Stargazer originals, but all are fun, entertaining and helpful learning tools.

This class will focus on four regions prominent in the summer: circumpolar, macho quadrangle, Sagittarius's tea party, and the Milky Way triangle.

We will also learn about planets--where to look for them and how to tell them from the stars. By chance, six planets--Mercury, Venus, Mars, Jupiter, Neptune and Uranus--will be out in the early evening.

No prior experience is required, and participants need no equipment beyond materials for taking notes if they wish. The course closely follows the Stargazer's book, A Beginner's Guide to Learning the Night Sky, so it will be available for $25. However, purchasing the book is not required and loaner copies may be borrowed at no cost.

All ages are welcome although children at least 10 years of age have worked out the best in prior classes. Since parents are the best judge of their children's interest, attention span and potential for disruptive restlessness, they can best decide the appropriateness of this course for their children and vice versa.

There is no charge for the course, but registration is requested for planning purposes. To register or learn more, contact the Stargazer at 254-753-6920 (home), 254-723-6346 (cell) or

July 12, 2008
Stargazer #483B

Telling Planets from Stars

Currently early evening stargazers see Saturn and Mars setting in the west and Jupiter rising in the southeast. But in a sky full of stars, telling which ones are the planets isn't easy.

To the naked eye, planets appear as starlike points of light, and like stars, they are of different brightness and colors. So how can one tell which are planets and which are stars?

There are five naked-eye planets--Mercury, Venus, Mars, Jupiter, and Saturn--but the number of these planets visible on any given night varies from none to five. And the number even changes throughout the night as planets rise and set.

For casual stargazers, there is no foolproof way to pick out the planets from among stars, but the following pointers can help.

First, note the brightness. Venus and Jupiter always outshine all stars, and Mercury, Mars, and Saturn usually outshine all but the brightest stars. So brightness is one clue.

Second, you've likely heard that "stars twinkle, planets don't," which is often true. But this difference is subtle and varying. Twinkling is caused by turbulence in Earth's atmosphere, so that greater turbulence produces more twinkling while steadier air makes for less twinkling. So, when the stars twinkle noticeably, look for any brighter objects that don't.

Third--and this is very helpful--relates to where in the sky to look. Planets orbit the Sun on nearly the same plane, so they all closely follow the Sun's path across our sky, called the ecliptic. The Moon orbits Earth on nearly this same plane, so it too travels close to the ecliptic.

Like the Sun, the planets (and Moon) generally rise in the east and set in the west. Facing south with your arms stretched out slightly more than 180 degrees, any visible planets will be in front of your arms--never behind you or straight overhead. All that are above the horizon will be somewhere along the great ecliptic arc beginning in the east, rising and tilting to the south, and ending in the west.

One caveat. The season and time of night affect the ecliptic's exact rising and setting points, making them sometimes a little left or right of due east and west. And the amount of southerly tilt varies so that sometimes the ecliptic is tilted more than half way down toward the southern horizon while at other times it reaches nearly straight up. Still, knowing the approximate path is useful in identifying planets.

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--never deep into the night. The outer planets, when not passing behind the Sun, might rise or set, and thus be seen, any time during the night.

This column always tells which naked-eye planets are visible in the morning and evening, and where to look for them. More precise information is available in monthly magazines like Sky & Telescope and Astronomy, and from websites like,, and

  • Next Two Weeks. Avg. sunrise: 6:36 a.m.; avg. sunset: 8:33 p.m. (exact for Waco, TX)
    * Tomorrow (July 13) evening the Moon is to the right of Scorpius' brightest star Antares in the south.
    * Friday, July 18, the full Moon is called Thunder Moon and Hay Moon.
    * The Moon is at 3rd quarter July 25.

  • 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: Reddish Mars and brighter Saturn are low in the west with Jupiter climbing higher in the east.
    Morning: An hour before sunrise Mercury is very near the east northeastern horizon as Jupiter is setting in the west southwest.

June 28, 2008
Stargazer #482

Evening Rendezvous in the West

Over the next two weeks Saturn and Mars, Leo's brightest star Regulus, and the Moon will rendezvous low in the west just after dusk. It's an event to begin watching nightly.

This evening ruddy-colored Mars is three moonwidths to the lower right of the slightly brighter Regulus with brighter Saturn to their upper left. An hour after sunset as twilight turns into darkness, the trio will be hard to miss two and one-half fist-widths (held at arm's length) above the western horizon.

Monday and Tuesday evening Mars passes within two moonwidths to the upper right of Regulus. Their close proximity provides an opportunity to observe how "stars twinkle, planets don't." While this adage is usually true, it is less obvious when objects are near the horizon and seen through more of Earth's atmosphere. There even planets can twinkle some.

By continuing to observe nightly, you'll see Mars approach Saturn. July 4, when you're out watching fireworks, notice how the three are aligned and almost equally spaced.

July 5 the Moon joins the trio to their lower right. The four will be aligned from the upper left to lower right.

The next evening presents what might be the highlight of the entire show as the crescent Moon moves to the trio's left. With your hand extended at arm's length, you can hold the Moon, two planets and a star in the palm of your hand.

By July 7 the Moon is well to the trio's upper left, and getting bigger and brighter. But the show still isn't over.

July 8-11 Mars passes less than two moonwidths to Saturn's lower left. Their closest approach comes July 10 when they are little more than a moonwidth apart.

  • Next Two Weeks. Avg. sunrise: 6:29 a.m.; avg. sunset: 8:37 p.m. (for waco, TX)
    * Sunset tomorrow night is the latest for the year at latitude 30 degrees North.
    * Monday morning the Moon is less than 4 moonwidths below the Pleiades star cluster low in the east.
    * Tuesday morning, an hour before sunrise low in the east, look for a thin crescent Moon and the star Aldebaran to its right a little more than the width of your fist held at arm's length; between them nearer the horizon is Mercury, the same brightness as the star.
    * Wednesday is the midpoint of the year 2008, and the Moon is new.
    * Friday the Earth is at aphelion, its farthest from the Sun in its elliptical orbit, at 94.3 million miles.
    * Friday evening, an hour after sunset, the thin crescent Moon is to the left of the Beehive cluster low in the west -- use binoculars to spot the cluster.
    * July 9 the Moon is at 1st quarter, and Jupiter is at opposition (on the opposite side of Earth from the Sun) when it rises at sunset, is up all night and sets at sunrise.

  • 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 and Mars are low in the west; Jupiter is rising in the east.
    Morning: Mercury is near the eastern horizon an hour before sunrise; Jupiter is low in the southwest.

  • StarDate. A reader asked Stargazer to list the stations that carry the University of Texas McDonald Observatory's popular daily "StarDate" radio program. The two-minute program is carried by over 500 stations nationwide and 25 in Texas--far too many to list here. So here's how to find a station in your area. On the Internet go to StarDate. Under the Radio button, select Find Affiliates, then enter your state. Up will pop a list of cities, stations (with their frequencies) and air times.

June 14, 2008
Stargazer #481

Tunguska Event

A hundred years ago, on June 17, 1908, an event occurred over a remote part of Russia, the likes of which had not been seen before or since. Something exploded 3-6 miles in the air with far more power than the atomic bomb dropped over Hiroshima in 1945.

A little after 7 a.m. near the Podkamennaya Tunguska River in Siberian Russia, the sky blazed with light, the ground shook like an earthquake, thunder-like explosions were heard and blasts of hot wind blew people off their feet. Many who witnessed--and survived--the event feared the world was coming to an end.

The result was the virtual devastation of a forest area some 30 miles in diameter where an estimated 80 million trees were felled with their bark and branches stripped off. Surely any animals and humans in the ground-zero area would have been killed.

Fortunately the explosion happened over a largely uninhabited area, but it has been calculated that if it had occurred 5 hours later, it would have exploded over St. Petersburg. Given the devastation of Hiroshima with a much less powerful bomb, one shutters to think of the effects of this event over a large city.

So what was it? Since it happened years before the creation of nuclear bombs and when human flight was still in its infancy, it was almost certainly of natural rather than human origin.

A number of hypotheses have been put forth, including a few rather wild ones. Some have suggested that Earth was impacted by a black hole or antimatter; others have postulated that an alien spacecraft exploded while trying to land on Earth.

1927 Leonid Kulik expedition photo of fallen trees

While none of these ideas can be unequivocally disproved, all lack the supporting evidence to be taken seriously. Most scientists think a comet or meteoroid several 10's of meters in diameter exploded shortly before impacting Earth's surface--a hypothesis backed by good, although not conclusive, evidence.

So what's the prospect of a repeat? No one can predict for sure, but the late Gene Shoemaker, an impact expert, estimated that these events might be expected once every 300 or so years.

  • Next Two Weeks. Avg. sunrise: 6:24 a.m.; avg. sunset: 8:37 p.m. (for Waco, TX)
    * Wednesday's full Moon is called Rose Moon, Flower Moon, and Strawberry Moon.
    * Friday is the summer solstice, the longest day of the year, marking the beginning of summer.
    * After rising around 10:30 p.m. the evening of June 19, the Moon and Jupiter travel across the sky together all night.
    * The Moon is at 3rd quarter June 26.

  • 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: As darkness falls Mars and Saturn are setting in the west.
    Morning: Brilliant Jupiter, rising soon after 10 p.m. is seen in the southwest by morning while Mercury begins its morning stint low in the east.

May 31, 2008
Stargazer #480

Where Are Venus and Mercury?

Other than the Moon and fleeting objects like bright meteors and artificial satellites, the planet Venus is the brightest body in our night sky. It far outshines all the stars and other planets. And Mercury, although most have never seen it, also gets brighter than any star.

But as bright as they are, these two innermost planets orbit nearer the Sun than does Earth and thus are seen only in the morning or evening, never in the middle of night. When blazing in the morning sky, Venus is called the "morning star," and when in the evening, the "evening star."

At the moment, neither Venus nor Mercury is readily visible as both are hidden in the glare of the Sun.

Venus spends some eight months as the "morning star" before hiding from view for some six weeks while passing behind the Sun (a position called superior conjunction). It then becomes the "evening star" for eight months before again hiding from view for another six weeks when it passes between the Earth and Sun (called inferior conjunction).

This 584-day cycle, repeated year after year, was well known to several ancient civilizations, like the Mayas of Central America for whom Venus was an important god.

This year Venus passes directly behind the Sun June 8. It then begins its stint as the "evening star" in early July, and remains in the evening sky the rest of 2008.

Mercury follows a similar but more rapid pattern with a 116-day cycle. Being nearest the Sun, Mercury speeds around our star faster than any other planet, zipping along at 107,000 mph and completing its orbit in a mere 88 Earth-days. (For comparison, Venus travels 78,000 mph, orbiting the Sun every 225 Earth-days, and Earth, traveling 67,000 mph, orbits the Sun every 365 days.)

Owing to its more elliptical and tilted orbit, Mercury's periods of visibility and invisibility are more varied. On average, it spends some six weeks in the morning sky, two weeks hidden in the glare of the Sun, six weeks in the evening sky and another two weeks in the Sun with the cycle being repeated about three times each Earth year.

June 7, the day before Venus is at superior conjunction behind the Sun, Mercury by coincidence is at inferior conjunction between the Earth and Sun. So as Venus is about to emerge in the evening sky, Mercury will soon appear in the morning sky.

  • Next Two Weeks. Avg. sunrise: 6:23 a.m.; avg. sunset: 8:32 p.m. (for Waco, TX)
    * The Moon is new Tuesday.
    * The evening of June 7 the crescent Moon is below Mars with the Beehive cluster to the lower right.
    * The next evening the Moon is below the star Regulus with Saturn above them.
    * The Moon is at 1st quarter June 10.
    * June 11 is the year's earliest sunrise at latitude 30 degrees north.
    * June 13 is Friday the 13th, an unlucky day for the superstitious, but they're in luck as this is the only one this year.

  • 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: Mars is three fists (held at arm's length) above the western horizon with Saturn the brightest object two fists to Mars' upper left.
    Morning: Jupiter is the brightest object in the south.

May 17, 2008
Stargazer #479

Mars Passes Through the Beehive

The night sky is about to present an early evening show well worth a look--not a flashy display like a meteor shower or lunar eclipse, but still one to behold. The planet Mars is approaching the Beehive, a subtle but fairly large star cluster, which it will pass through May 21-23.

Although much smaller, Mars greatly outshines the stars of the cluster due to their greater distance. Mars is a modest-sized planet--twice the diameter of our Moon and half that of Earth. And like all planets and moons, Mars shines by reflecting sunlight. Every other year when its orbit brings it near Earth, it grows brighter, sometimes outshining the stars and rivaling bright Jupiter. But when further away--like now--it appears only as a moderately bright and slightly reddish star. At its nearest, Mars comes within 34 million miles of Earth.

The Beehive is composed of over 200 stars 515 light years away--more distant than most of the naked-eye stars in our night sky. Like our Sun, each star in the Beehive cluster emits light from the nuclear reactions deep within its core. The cluster's brighter stars are spread over a region of space 11 light years in diameter. For comparison, Alpha Centauri, our nearest neighboring star, is 4 light years away, and Sirius, our night sky's brightest star, is less than 9 light years distant.

Yet as huge as the cluster is, from Earth it covers an area only somewhat larger than a full Moon. To the naked eye, it looks like a faint, softly glowing stellar cloud with individual stars eluding detection. Through binoculars, however, the Beehive is at its dazzling best as several dozen stars swarm into view, giving rise to its name. Unless viewed at very low power, the entire Beehive won't fit into a telescope's field of view.

Mars spends three nights passing through the cluster, but several nights before and after will also be exciting, so start looking now. Here's how to find this beautiful sight.

Around 10 p.m., face west--a little to the left of where the Sun went down. The width of your fist held at arm's length being 10 degrees, look for the bright star, Procyon, 16 degrees above the horizon. Mars, a little fainter than the star, is 20 degrees further up. Don't be confused by Gemini's almost equally bright stars, Pollux and Castor, 15 degrees to the lower right of Mars. Using binoculars--any size will do--be prepared to have your socks knocked right off your feet.

  • Next Two Weeks. Avg. sunrise: 6:27 a.m.; avg. sunset: 8:24 p.m. (for Waco, TX)
    * Monday's full Moon, called Planting Moon and Milk Moon, occurs almost at apogee when the Moon is farthest from Earth in its elliptical orbit, thus it appears slightly smaller than most full Moons.
    * The morning of May 24 the Moon is below Jupiter.
    * The Moon is at 3rd quarter May 27.
    * In the early evenings of May the Milky Way seems to disappear as it lies flat around the horizon.

  • 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 is very low in the west at dusk with Mars higher in the west and Saturn well to Mars' upper left.
    Morning: Jupiter is the brightest object in the south.

  • Star Party. The Central Texas Astronomical Society hosts its free monthly star party May 24 at the Waco Wetlands beginning at 8:30 p.m. An indoor program is followed by a laser-pointer guided tour of the night sky and telescope viewing, weather permitting. For directions see my Website.

May 3, 2008
Stargazer #478

Phoenix to Look for Martians

Imagine a Martian exclaiming to a friend, "The Earthlings are coming again, and this time they're looking for us!"

That's what any thinking Martians could be saying--if any existed, which they probably don't. But what about non-thinking Martians, or long-ago Martians? Do they or did they exist?

That's what NASA is hoping to learn more about when the Phoenix spacecraft lands on Mars May 25. While Phoenix isn't actually carrying Earthlings, it is packed with an array of our scientific instruments to analyze the chemistry and mineralogy of Martian soil and ice, looking for indications of current or past life.

As countless science fiction books and movies can attest, we have long been fascinated with the idea of life on Mars. Yet early explorations dampened our hopes for actually finding life. Mars is incredible cold, it seemed bone-dry, and its atmosphere is too thin and oxygen-poor to sustain life as we know it.

Recent discoveries, however, have resurrected our hopes. Strong evidence for the presence of water, a prerequisite to life, has been found in the form of gaseous water vapor in Mars' atmosphere and water ice a short distance beneath Mars' surface. There are also indications that liquid water flowed on Mars as recently as 100,000 years ago. Geologically, that's like yesterday. Finally, scientists have found life thriving here on Earth in extreme conditions previously thought far too harsh for life even to exist, much less thrive.

According to NASA, "It is possible that bacterial spores can lie dormant in bitter cold, dry, and airless conditions for millions of years and become activated once conditions become favorable." If so, then "such dormant microbial colonies may exist" on Mars.

NASA's Mars Exploration Program, of which Phoenix is one component, has several goals: learn about Mars' climate and geology; determine whether life ever arose on Mars; and prepare for human exploration.

The specific goals of the Phoenix Mission are to study the history of water in Mars' north polar region, search for evidence of a habitable zone, and assess its biological potential.

So, while Phoenix might not actually find any Martians, it could well give us a much better idea of whether they exist, or have existed in the past.

  • Next Two Weeks. Average sunrise: 6:36 a.m.; average sunset: 8:14 p.m. (for Waco, TX)
    * Monday morning in the hours before dawn, the Eta Aquarid meteor shower peaks without interference from the new Moon.
    * Tue. evening a very thin crescent Moon is above Mercury with the star Aldebaran to their left just above the west northwestern horizon an hour after sunset; use binoculars.
    * Fri. evening the Moon is below Mars.
    * The evening of May 10 the bright Moon is above Mars and grazes the Beehive star cluster; use binoculars to see the cluster to the Moon's upper right.
    * May 11 the Moon is at 1st quarter.
    * The evening of May 12 the Moon is to the left of Saturn with the fainter star Regulus below the planet.
    * The early evening of May 13, Mercury is at it best, being at its highest above the setting Sun (called greatest elongation.)

  • 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 is near the west northwestern horizon at dusk with Mars high in the west and Saturn higher in the south.
    Morning: Jupiter is the brightest object in the south.

April 19, 2008
Stargazer #477

The Big Dipper As Your Nighttime Guide

The Big Dipper is probably the night sky's most familiar star pattern, and it's no wonder. It's visible from most of the northern hemisphere where over half of all humans live. And it really looks like a large dipper or ladle, although other cultures associate it with other objects such as a plow, a wagon or a bear. As well known as it is, the Big Dipper isn't an official constellation, but rather is a part of the huge constellation Ursa Major, the Big Bear.

Whether seen as a bear, a dipper or something else, the Big Dipper is a useful pattern in the night sky. The end stars of the bowl point to the North Star (also named Polaris), and are called the "pointer stars." The North Star is directly above Earth's North Pole and seems to never move in our sky. As Earth revolves on its axis every 24 hours, the Big Dipper swings around in a big counterclockwise circle with the pointer stars always showing the way to Polaris.

The old slave song "Follow the Drinkin' Gourd," referring to the Big Dipper, gave directions to run-away slaves traveling at night. The drinking gourd always pointed to the North Star, directing them north to freedom in Canada.

Big Dipper

While it still points modern-day stargazers to Polaris, it helps in other ways as well. The curved handle "arcs to Arcturus," a bright reddish star 30 degrees away in the constellation Bootes. (The width of your fist held at arm's length is 10 degrees.) The spring constellation Leo, the Lion, when above the horizon, is seen 40 degrees from the bottom of the bowl, and winter's Gemini and Auriga are 45 degrees in front of the bowl.

During the evenings of fall, the Big Dipper swings below the horizon and is all but absent from our sky. According to an old Stargazer legend, it's during the fall that the dipper is near the Earth filling its bowl with water. In the winter, with the dipper east of Polaris, the water is frozen solid. During spring, with the dipper upside down above Polaris, the thawed water pours spring rains upon Earth. Then during the summer, with the dipper to the west of Polaris, the land is hot and dry because the dipper has no water left to cool and moisten the Earth.

  • Next Two Weeks. Avg. sunrise: 6:48 a.m.; avg. sunset: 8:05 p.m. (for Waco, TX)
    * Tomorrow's full Moon is called Grass Moon and Egg Moon.
    * Wed. morning the Moon is to the right of the reddish star Antares.
    * The morning of Apr. 27 the Moon is below Jupiter.
    * The Moon is at 3rd quarter Apr. 28.
    * May 1 is May Day, a cross-quarter day celebrating the middle of spring.
    * The evening of May 2 Mercury passes near the Pleiades star cluster just above the western horizon an hour after sunset; binoculars will help.

  • Naked-eye Planets. Evening: Mars is high in west with Saturn high in the south. Morning: Venus is sinking into the rising Sun as Jupiter is climbing higher in the southeast.

  • Star Party. The Central Texas Astronomical Society hosts a free public star party April 26 at the Waco Wetlands beginning at 8 p.m., weather permitting. For directions to the Wetlands, see MAPS & DIRECTIONS elsewhere in this website.

April 05, 2008
Stargazer #476

Cosmic Sizes and Distances

Tuesday evening the crescent Moon will graze the Pleiades star cluster low in the west after dark in what should be a lovely sight to naked eyes and dazzling in binoculars.

As it passes in front of some of the stars, it might seem as if the huge Moon is swallowing the tiny stars.

Such occurrences provide excellent examples of how misleading appearances can be, especially regarding sizes and distances in the cosmos. It's easy to see how our ancient ancestors formed what we now know to be such wrong conceptions of the universe.

There's no question the sky looks big, and the Sun, Moon, stars and other night sky objects are far away. But only in recent decades have we come to realize just how big and how far away.

One of the largest appearing objects, the Moon, is really tiny with its 2,159-mile diameter being less than the width of the U.S. And orbiting Earth at an a average distance of only 239,000 miles, it's little more than an extension of Earth.

And while the Sun and Moon appear the same size, that too is deceiving. The Sun's diameter of 864,000 miles is 400 times that of the Moon (and over 100 times Earth's diameter). The Sun and Moon look of equal size because, by coincidence, the Sun's average distance of 93 million miles happens to be 400 times that of the Moon's average distance.

But even all these sizes and distances pale in comparison to those of the Pleiades. Each of those 100 or so "tiny" stars is a sun, many larger than our own. And their distance? How about 2.4 quadrillion miles (add 14 zeros!). Such a large number is so cumbersome astronomers use a unit of measure called a light year--the distance light travels in a year (5.9 trillion miles). So really the Pleiades are only 407 light years away--relatively nearby, cosmically speaking.

It quickly gets far more mind-boggling. Our Milky Way galaxy, 100,000 light years in diameter, is but one of countless billions of galaxies, most of which are thousands to millions of light years distant from each other. So while seeing the Moon graze the Pleiades is aesthetically beautiful, it gives no clue as to the true enormity of our universe.

  • Next Two Weeks. Avg. sunrise: 7:04 a.m.; avg. sunset: 7:55 p.m. (for Waco, TX)
    * The Moon is new today.
    * Fri. evening the Moon is near Mars in the early evening, and pulls within one moonwidth before they set around 2 a.m.
    * The Moon is at 1st quarter Apr. 12.
    * The evening of Apr. 14 the Moon is to the right of Saturn, and the next evening to the planet's lower left with the slightly less bright star Regulus to the right.

  • 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: Mars is overhead with Saturn high in the southeast. Morning: Brilliant Venus hovers near the eastern horizon shortly before sunrise; Jupiter is the brightest object higher in the southeast.

  • Eclipse Countdown. It's now only 16 years until the April 8, 2024, total eclipse of the Sun passes directly over the heart of Texas. Live healthily so you can join me in watching it.

  • Astro Milestones. Apr. 12 is the 47th anniversary of Yuri Gagarin's 1961 historic 108-minute orbital flight around Earth--an early Space Age milestone. Astronauts now spend months in Earth orbit in the International Space Station.

March 22, 2008
Stargazer #475

Pirates' Eye Patch

Have you ever wondered why pirates are often shown with an eye patch? I've assumed the patch covered a damaged or missing eye, the result of their notoriously violent lives.

But recently a friend offered an another explanation. Perhaps the eye patch had to do with dark adaptation, something close to the hearts of stargazers.

Just as eyes automatically focus when viewing at different distances, they also adjust to the amount of light available. In bright light, our eyes' pupils partially close, allowing in less light, whereas in under low-light, the pupils open wide so more light can enter. In addition to the pupil responses, there are also changes in the retina--the part of the eye that receives the light--that help the eyes adjust.

We're familiar with this. When we walk into a dark movie theater it's often hard to find a seat until our eyes begin to adjust to the darkness. And when we leave, the brighter lights are often uncomfortable until our eyes adjust to the increased light.

Stargazers typically view very faint objects, so we want our eyes as dark adapted as we can get them. Under dark skies, our wide-open pupils and the changes in the retina make it easier to see the faint fuzzies we like to view. However, a second or two of bright light from a flashlight or auto headlight ruins night vision, making it impossible to see faint objects until our eyes readjust to the dark--something that can take several minutes.


Now back to the pirates. On ships where lighting was with candle lanterns, it was rather dark in the lower decks. After being below for a while their eyes would adapt to the low-light and they could see. But if they were to briefly go topside, the bright light would ruin their dark-adapted eyes, making it difficult to see when they went back below.

So, as the story goes, when going topside they covered one eye with a patch so that eye would still be dark adapted when they went back down.

According to my ophthalmologist, Dr. John Quinius, the story could be plausible. Our eyes' pupils normally react in tandem, so an eye patch wouldn't keep the covered eye's pupil opened wide. But changes in the retina occur individually, so the covered eye might conceivably remain more dark adapted.

Of course, if this was common practice, one would think all sailors of the day would have done it, yet I don't recall pictures of non-pirate sailors with eye patches. Whether true or fanciful, it makes for a good--and plausible--story.

  • Next Two Weeks. Avg. sunrise: 7:21 a.m.; avg. sunset: 7:46 p.m. (for Waco, TX)
    * Monday morning Venus is two moonwidths to the upper left of Mercury just above the eastern horizon 30-45 minutes before sunrise.
    * The Moon is at 3rd quarter Mar. 29.
    * The morning of Apr. 4 a thin crescent Moon is above Venus near the eastern horizon 30 minutes before sunrise.

  • 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: Mars is high overhead with Saturn high in the southeast.
    Morning: Venus and Mercury are near the eastern horizon 30 minutes before sunrise with Jupiter higher in the southeast.

  • Star Party. The Central Texas Astronomical Society hosts its free monthly star party Mar. 29 at the Waco Wetlands beginning at 7:30 p.m. After an indoor program there will be a guided tour of the night sky and telescope viewing, weather permitting. For directions/map see my Website.

March 8, 2008
Stargazer #474

Why Is Easter So Early This Year?

If it seems like Easter comes early this year, you're right. Based on the start of spring and the phase of the Moon, this year's March 23 is almost as early as Easter can ever be.

Most holidays are fixed to a specific date, like Independence Day on July 4 and Christmas on December 25. But two widely celebrated holidays vary from year to year--Thanksgiving and Easter.

Thanksgiving, a religious holiday in the minds of many, is officially a civil holiday. It was originally a harvest festival in what is now Canada in the late 1500s, and in what became Massachusetts in the early 1600s. In some, but not all, of the earliest years of U.S. history Thanksgiving was celebrated by annual presidential proclamations through 1815.

Then there were none until President Lincoln resumed the holiday as the last Thursday of November. In 1941, Congress and President Franklin Roosevelt set the date as the fourth, rather than last, Thursday in November, reportedly succumbing to pressures from the business community to extend the time for Christmas shopping.

Easter, however, is a holiday of Christianity. It celebrates the religion's foundational belief that following his execution, Jesus briefly came back to Earthly life and then ascended into heaven. In that this event was linked to the Jewish Passover, the date for Easter was originally linked to Passover.

The date for Passover is based on the Hebrew lunisolar calendar that regards both the solar (seasonal) year and the phases of the Moon. Lunisolar calendars, which have been used by many cultures, probably predate all modern religions.

So given its roots, it's not surprising that Easter is based on a lunisolar calendar and linked to the spring season. No longer tied to Passover, Easter is now celebrated on the first Sunday following the full Moon which falls on or after March 21, the symbolic first day of spring. (Astronomically, the first day of spring varies from March 19-21.)

Unless the formula is modified, Easter will never fall earlier than March 22 or later than April 25.

  • Time Change. Tonight before retiring, set your clocks forward 1 hour ("spring forward") from Standard to Daylight- Saving Time.

  • Next Two Weeks. Avg. sunrise: 7:39 a.m. CDT; avg. sunset: 7:37 p.m. CDT. (for Waco, TX)
    * Wednesday evening the Moon is above the Pleiades star cluster.
    * Friday evening the 1st quarter Moon is to the right of Mars high overhead.
    * The evening of Mar. 18 the Moon is above Saturn with the star Regulus between them, and the next evening is below the planet.
    * Mar. 19 is the spring (vernal) equinox, the first day of spring.
    * The Mar. 21 full Moon is called Sap Moon and Crow 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: Mars is high overhead with Saturn well up in the east.
    Morning: Brilliant Venus and Mercury are hovering near the east southeastern horizon at dawn while Jupiter is higher in the southeast and Saturn is setting in the west.

  • Astro Milestones. Mar. 13 is the 227th anniversary of William Herschel's 1781 discovery of Uranus from Bath, England. Mar. 14 is the 129th birthday of Albert Einstein (1879-1955).

February 23, 2008
Stargazer #473

Happy Leap Day

Most of us seem to prefer it when things come out even. A Dollar Store has more appeal than a Ninety-Eight-and-One-Half Cent Store, and it makes more sense that a bottle of drink is 12 rather than 12.17 ounces. And wouldn't it be easier if they just said gasoline is $3 a gallon rather than $2.99.9? It just seems to simplify life a bit when things come out even.

Unfortunately, Mother Nature doesn't share that sentiment when it comes to time. Two of our more important measures of time are based on natural phenomena. A day is one rotation of Earth on its axis, and a year is one revolution of the Earth around the Sun.

If Mother Nature shared our compulsive need for orderliness, she would have made one year an exact number of days, but she didn't. In the time Earth revolves around the Sun (one year), our home planet rotates on its axis 365.2422 times, thus a year is a fraction short of 365 1/4 days.

Since our calendars (and minds) can't easily handle having a 1/4-day each year, we even it out by adding a whole day to the calendar every four years. By convention, we add that day to each year that is evenly divisible by 4. That day, Feb. 29, is called Leap Day, and the year is called Leap Year. In the U.S.,it's easy to remember as it coincides with presidential election years. So, next Friday will be Feb. 29, not Mar. 1.

When it comes to months, Mother Nature is even more untidy. It takes our Moon 29 1/2 days -- approximately one month ("moonth") -- to orbit Earth. Since we don't like fractions of days, we round a month to 30 days. But even that doesn't quite work as there aren't an even number of months in the year. So we add an extra day to some months -- except February which got short-changed.

See how messy all this is. Mother Nature could have been so much more orderly if she had Earth revolve around the Sun in exactly 360 days, and the Moon orbit Earth in exactly 30 days. Then those of us with compulsive tendencies could rest easier.

On the other hand, maybe a little disorder keeps life more interesting. In any case, happy Leap Day.

  • Next Two Weeks. Avg. sunrise: 6:56 a.m.; avg. sunset: 6:27 p.m. (for Waco, TX)
    * Wed. morning Mercury is 2 moonwidths above the much brighter Venus very low in the east southeast 45 minutes before sunrise.
    * Thurs. morning the 3rd quarter Moon is to the right of the star Antares, and the next morning is to the star's lower left.
    * The morning of Mar. 2, the crescent Moon is to the right of Jupiter low in the southeast, then the next morning is below the planet.
    * The morning of Mar. 5 a thin crescent Moon is just to the lower right of Mercury with Venus to the lower left; all are within the same binocular field of view near the east southeastern horizon shortly before dawn.
    * The Moon is new Mar. 7.

  • Naked-eye Planets. Morning: Mercury and brilliant Venus are near the east southeastern horizon with bright Jupiter to their upper right; Saturn is setting in the west. Evening: Mars is high overhead as Saturn rises in the east.

  • Star Party. The Central Texas Astronomical Society hosts its free monthly star party tonight at the Waco Wetlands beginning at 7 p.m. After an indoor program there will be a laser-pointer guided tour of the night sky and telescope viewing. For directions and map see my Website. (Canceled if raining.)

February 09, 2008
Stargazer #472

Total Eclipse of the Moon

Hope you got up early Feb. 1 to see Venus and Jupiter team up low in the east. The two brightest planets were dazzling, even if at an inconvenient hour. Now comes another show and at a much more agreeable time for most of us.

The evening of Feb. 20 will feature a total eclipse of the Moon over most of the western world, including the U.S. The earliest stage begins at 6:35 p.m. when subtle shadings of the Moon's surface become visible. Partial eclipse starts at 7:43 when the Moon begins entering the darkest part of Earth's shadow. The Moon becomes totally eclipsed at 9:01, reaching mid-eclipse at 9:30. It begins emerging from Earth's shadow at 9:52, with partial eclipse ending at 11:09, and the final stage ending at 12:17 a.m. You can't ask for better timing.

During totality, when the Moon is wholly within Earth's shadow, it will dim considerably, but it's not likely to disappear. Depending upon Earth's atmospheric conditions, the Moon will appear somewhere between a dark gray and a beautiful coppery orange. We won't know which until it happens.

Lunar Eclipse

Twice during each of the Moon's 29 1/2-day orbits around our planet, the Sun, Earth, and Moon align. At new Moon, the Moon is between Sun and Earth, and at full Moon, Earth is between the Sun and Moon.

If the alignments were exact, every new Moon would result in a total eclipse of the Sun with the Moon passing in front of the Sun, and every full Moon would cause a lunar eclipse with the Moon moving through Earth's shadow. But our Moon's orbit is a bit out-of-level with Earth's orbit around the Sun, so solar and lunar eclipses don't happen monthly. During most new Moons, the Moon passes just above or below the Sun's disk. And during most full Moons, the Moon passes just above or below Earth's shadow.

While total lunar eclipses aren't rare, they are infrequent. In the past 20 years our part of the world has seen fewer than a dozen good ones, most recently last August before dawn.

The next good one won't come until December 2010, and it happens after midnight, so let's hope for clear skies for time.

  • Next Two Weeks. Avg. sunrise: 7:09 a.m.; avg. sunset: 6:16 p.m. (for Waco, TX)
    * The Moon is at 1st quarter Wed.
    * Fri. evening the Moon is near Mars and the star El Nath.
    * The Feb. 20 full Moon is called Snow Moon, Hunger Moon and Wolf Moon.
    * The morning of Feb. 21 the Moon is below Saturn and to the left of the star Regulus.

  • 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: Mars is high overhead as Saturn rises by 7:30. Morning: "Morning star" Venus and Jupiter are low in the southeast with Saturn the brightest object low in the west.

  • Astro Milestones. Feb. 15 is the 444th birthday of Galileo Galilei (1564-1642). Feb. 18 is the 78th anniversary of Clyde Tombaugh's 1930 discovery of Pluto from Lowell Observatory in Flagstaff, Arizona. Feb. 19 is the 535th birthday of Nicolaus Copernicus (1473-1543).

January 26, 2008
Stargazer #471

The King and Queen Meet in the Morning

Friday morning (Feb. 1), Jupiter, the king of the sky gods, and Venus, the queen, pass breathtakingly close low in the east southeast as dawn begins to break.

If you're not a morning person, make this an exception as the sight will be worth getting up for. And if you are normally up and out in the mornings, you'll want to start watching now as the drama unfolds. Currently Venus, the brighter of the two, is above Jupiter, but each morning she coyly edges two moonwidths closer. When she catches him, she'll be just a moonwidth to his left.

But that's not all. Another piece of the drama is occurring further up as the crescent Moon is marching toward the couple at the pace of a moonstride each morning. (Hold your hand at arm's length while making a "hook 'em horns" sign; the distance between your extended fingers is a moonstride.)

The morning of the royal rendezvous, look for the crescent Moon to the right of Scorpius' brightest star, the reddish Antares, higher in the southeast.

Venus & Jupiter

But the show doesn't end Feb. 1. The morning of Feb. 3 a thin crescent Moon smiles down upon the pair from their upper right, and then the next morning is below them nearer the horizon.

Other than an occasional meteor or flaring satellite, the Moon, Venus, and Jupiter are the three brightest objects in the night sky. So when they all come together, it's a sight you won't want to miss.

Postscript: Readers with telescopes (or even binoculars) will want to zoom in on Jupiter as it is now two moonwidths to the left of a globular star cluster, M22. In binoculars M22 looks like a fuzzy out-of-focus star, larger but much fainter than Jupiter. Telescopes, however, begin to reveal its true nature.

Jupiter's dominating brightness gives the impression that M22 is one of his lesser subjects, but not so. At 400 million miles away (that's about 35 light-minutes), Jupiter is a next door neighbor compared to M22's distance of 10,000 light-years. Vastly more imposing than a mere planet, M22 contains a half million suns.

  • Next Two Weeks. Avg. sunrise: 7:21 a.m.; avg. sunset: 6:04 p.m. (for Waco, TX)
    * The Moon is at 3rd quarter Tuesday.
    * Feb. 2 is Candlemas (and Groundhog Day), a cross-quarter day celebrating the middle of winter.
    * The Moon is new Feb. 6.

  • Naked-eye Planets.
    Evening: Mercury is near the western horizon a half hour after sunset, Mars is high and bright in the east, and Saturn rises by 8:30 p.m.
    Morning: Venus and Jupiter are low in the east as Saturn is mid way up in the west.

  • Star Party. The Central Texas Astronomical Society hosts its free monthly star party tonight at the Waco Wetlands beginning at 7 p.m. After an indoor program there will be a laser-pointer guided tour of the night sky and telescope viewing. (Canceled if raining.) See MAPS & DIRECTIONS elsewhere in this website.

January 12, 2008
Stargazer #470

Looking Forward to 2008

Standing at the beginning of 2008, the Stargazer extends his best wishes to all. Hopefully, 2007 was good for you, and that the new year proves even better.

As always, we can count on Mother Nature to feed our souls with glimpses of her awesome beauty--if we take the time to notice. Here are some night-sky delights to touch our deeper selves.

The morning of Feb. 1, just before dawn, the queen and king of the heavens, Venus and Jupiter, pass within kissing distance of each other--right out in the open for all to see.

The evening of Feb. 20 features a total eclipse of the Moon visible over the entire U.S.

The evenings of May 21-23, reddish Mars passes in front of the beautiful Beehive star cluster, producing what should be a stunning sight in binoculars and small telescopes.

The evenings of July 5 and 6 see Saturn, Mars and the star Regulus closely aligned and joined by a crescent Moon.

This year's always-popular August Perseid meteor shower will be better in the morning than evening with the best show expected in the wee hours of Aug. 12 from 3 a.m. (when the Moon sets) until dawn. Other favorable 2008 meteor showers are likely to be the Eta Aquarids in May, the Delta Aquarids in July, the Draconids in October, the Taurids in November, and the Ursids in December.

The evening of Aug. 13 Venus passes within a moonwidth of Saturn, then the early evenings of September will display some interesting groupings of Venus, Mars, Mercury and the Moon.

The evening of Dec. 1, in what is likely to be the most dazzling celestial show of the year, the night-sky's three brightest objects--the Moon, Venus, and Jupiter--congregate after sunset.

And as we speak, the MESSENGER spacecraft, launched in 2004, is making its first flyby of Mercury. Skimming a mere 125 miles above the planet's surface on Jan. 14, it is imaging unseen parts of the innermost planet, so be watching the news for never-before-seen photos of our neighbor. Only somewhat larger than our Moon, Mercury is the least explored planet, other than the remote Pluto, so in 2011 MESSENGER will return and begin orbiting the tiny planet for more extensive study.

For Venus lovers--and who isn't--she continues as the "morning star" until mid spring, swings behind the Sun in June, then in mid summer emerges as the "evening star" for the rest of 2008.

The final thing to expect this year is the unexpected. While many night sky events are as predictable as the sunrise, we're often treated to surprises, like Comet Holmes which burst on the scene in October 2007, and is still faintly visible. So stay tuned and we'll do our best to keep you informed.

  • Next Two Weeks. Avg. sunrise: 7:28 a.m.; avg. sunset: 5:51 p.m. (for Waco, TX)
    * The Moon is at 1st quarter Tuesday.
    * The evening of Jan. 19, the Moon is to the lower left of Mars which is to the lower right of the star El Nath high in the east.
    * The Jan. 22 full Moon is called Old Moon and Moon After Yule.
    * The evening of Jan. 24, the Moon is to the right of Saturn as they rise around 9 p.m.

  • Naked-eye Planets. Evening: Mars dominates the high eastern sky with Saturn rising in mid evening. Mercury is becoming visible just above the western horizon at dusk and is at its best a few days before to a few days after Jan. 21. Morning: Venus is in the east with Saturn high in the southwest and Mars setting in the west.

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