Skywatch July 2002

These scripts are written by members of the Albany Area Amateur Astronomers and read by the staff of the Dudley Observatory. All scripts are copyright and may not be reproduced without permission of the writer and the Dudley Observatory. Scripts are published to the web in the week following their recording. Daily scripts may be heard by calling 518-382-7584 after 5pm.

 

 NOTE: Times given in the scripts are all local Schenectady, New York time.

Monday, July 1st. Written by Joseph Slomka.

The Sun sets tonight at 8:38, with the night darkest at 10:53 PM. Dawn breaks at 03:05 AM, and ends with sunrise at 5:20.

As the Sun sets, Venus is the first planet to pop into view. It is only moderately high in the West, and gets lower daily. Venus, in a telescope or binoculars, presents a uniform brightness, due to sunlight reflecting off its perpetual cloud cover. This cloud cover is so thick that no optical views are possible. Only in the 1970's could scientists pierce this veil with either radar or heavily protected space probe.

To Venus' lower right, just above the horizon, lie Jupiter and Mars. If you are lucky to have a clear horizon, the pair will shimmer in our murky atmosphere. Jupiter is the brighter of the two, with Mars about a degree to the upper right.

A similar pair inhabits the dawn sky, again very close to the horizon. Saturn and Mercury are much closer together than Jupiter and Mars. Mercury is the brightest of the pair. Mercury becomes lower daily, while Saturn climbs higher.

On this beautiful moonless night, if we look east at twilight's end, a hazy white band of light seems to stretch from the North Pole to horizon. This band is commonly called "The Milky Way". Examination of the Milky Way with binoculars or telescopes reveals it to be a continuous band of stars or clouds of dust or gases. Our galaxy is a gigantic pinwheel, with several arms. Our Solar System is located in one of these arms. When we look at the Milky Way, we are seeing through this arm out into space. From Lyra to Sagittarius the Milky Way seems to divide in two. A giant dust cloud causes this "Great Rift". We can see similar dust clouds on other galaxies. If we follow the Milky Way to the horizon, we come upon the constellation Sagittarius. The center of our galaxy is located in that constellation, but we cannot see it due to dense star and dust clouds.

Tuesday, July 2nd. Written by Jonathan Cassidy.

We have lost most of the planets for the summer, where did they go? They are now in the morning because Saturn has swung around the far side of the sun and Mercury has gone by Earth in its quicker tighter orbit of the sun.

For the hearty among us we can see a very nice conjunction of planets Wednesday, tomorrow. The only difficulty, and why we need hearty souls, is that it can be seen only in the very early morning hours, around 4:45 AM.

Next week on Thursday July 8th we will be able to see Saturn with the old crescent moon and the next morning we will see Mercury together with the VERY old crescent moon. Just three days later we will see the young crescent moon near Venus, because the moon has passed the sun, in our sky, going the opposite direction of the planets

Thus the Moon can be observed going around the sun from east to west while the planets go around the sun from west to east. I expect this bothered some early astronomers.

Wednesday, July 3rd. Written by Ray Bogucki.

Four of the five bright planets that lined up in the western sky earlier this spring have formed two close pairs, one in the evening, and the other in the morning twilight periods. Mars and Jupiter lie close together low in the west just after sunset. Jupiter will pass behind the Sun at its conjunction on July 19, while the more rapid eastward motion of Mars will delay the Red Planet's conjunction until August 10.

In the early morning sky, Saturn continues its steady motion westward relative to the Sun, rising earlier each day. Mercury, which reached its farthest western elongation from the Sun ten days ago, is now dropping back toward the rising Sun. Yesterday, the two planets passed within a fraction of a degree of each other. They will still be close together tomorrow morning, although the hazy weather renders the morning twilit sky very bright, making binoculars a real help in finding the two planets. Next week they will be farther apart but easier to find. On Monday morning, before sunrise, the thin waning crescent Moon will act as a guide, lying just to the left of Saturn, while on Tuesday it will sit just to the left of Mercury.

On Saturday, at midnight, the Earth will reach aphelion, that point in its elliptical orbit where it is farthest from the Sun. This event occurs when the Earth is experiencing the hot, sticky weather known since antiquity as the "dog days of summer". This season was so named by the ancient astronomers, who knew that at this season, the Sun was making its closest approach to Sirius, the brightest star in the sky also known as the "Dog Star" from its location in the constellation Canis Major, the Big Dog. Some astronomers thought that the hot weather resulted from the combined heat given off by the Sun and Sirius. This was a curious assumption, since in the cold days of winter, when Sirius shone brilliantly in the night sky, there was very little evidence that it was radiating any significant heat to the Earth.

Thursday, July 4th. Written by Alan French.

The Sun sets tonight at 8:37 PM. If you look toward the west about an hour later, you will quickly notice Venus shining brightly above the western horizon. Venus is now just in front of or to the lower right of the constellation Leo, the Lion. The brightest star in the constellation Leo, Regulus, is about 10 degrees above Venus. You can estimate this distance by holding your fist at arm's length. The distance across your knuckles is 10 degrees.

Stars appear bright in our sky because they are either relatively close to us or they are intrinsically bright. Regulus, the 20th brightest star in the night sky, lies fairly close to our Sun. It is 69 light years away, meaning the light you see tonight left Regulus in 1933.

Regulus is also known as Cor Leonis, which means "Heart of the Lion." When the skies are reasonably dark, but before Venus sets, you should be able to trace out Leo above the western horizon. Extending upward and the right of Regulus is a backwards question mark of stars. These form the lion's next and head. To the upper left of Regulus is a triangle of stars that mark the rear part of the lion. The one farthest from Regulus is Denebola, which comes from Deneb-el-Asad, or "Tail of the Lion."

Not everyone saw a lion in the stars we know as Leo. The Babylonians saw a Great Dog. Stars in the constellation have also been seen as a crayfish, a god of Thunder and Lightning, and a sleeping woman.

The westward motion of the stars and the eastward motion of Venus among the stars will bring Venus and Regulus closer together during the coming days. They will be closest next Wednesday night, when there will be a little over one degree between them - about one tenth their separation tonight. Watch them approach during the coming evenings.

The Moon will not rise until almost 2:00 AM tomorrow morning, so the beauty of the evening sky will be unhampered by Moonlight.

Friday, July 5th to Sunday, July 7th. Written by George Mileski

On Friday July 5th looking in the west, you will see Venus less than five degrees from the star Regulus in the constellation Leo the Lion. Regulus is to the upper left of Venus and in the days ahead they will be getting a lot closer. On Saturday at dawn looking in the east you will see two planets, Mercury and Saturn, Mercury is to the lower left of Saturn. Mercury is also brighter than Saturn. These planets are very low to the horizon so a pair of binoculars maybe a good idea. To the upper right of Saturn is the star Aldebaran and higher yet looking west is the crescent moon. 

In the east after dark look for the summer triangle. The triangle is Vega, Deneb and Altair the brightest stars of three separate constellations. They are so much brighter than their neighbors that the triangle is the prominant summer and early-autumn configuration. The most prominant of the constellations associated with the summer triangle is Cygnus, its main stars forming a cross, with Deneb at its top. Popularly known as the Northern Cross. Cygnus is a swan, in mythology, its tail at Deneb and its wings stretching beyond the cross's arms. The swan's neck extends to the foot of the cross, to the third-magnitude star Albireo.  

Altair is the brightest star in Aquila the eagle, a collection of third and fourth magnitude stars with a birdlike outline. Vega's constellation is the small but distinctive Lyra the harp. The brightest star in the southern summer sky is Antares, located in the fishhook shaped constellation Scorpius, which barely scrapes above the horizon on summer evenings. To find Antares, look at the summer triangle and follow a sight line from Deneb through the northern crosses long arm on to Antares, thats about 80 degrees.

Antares is distinctly orange. In Greek, Antares means "rival of Mars" and the name fits. When following the ecliptic, Mars often is near Antares and the two look almost identical. Antares has a diameter about 500 times our sun, its a red super-giant. If it were to replace the sun, It would easily enclose earth's orbit.     

Monday, July 8th. Written by Joseph Slomka.

The Sun sets tonight at 8:35, with twilight ending at 10:47 PM. Dawn breaks at 3:14 AM, with the Sun rising at 5:25.

Venus pops into view a few minutes after sunset, and, for most people, the only planet visible. As the sky darkens, another object appears just to Venus' left. This is the bright star Regulus, the main star of the constellation Leo, the Lion. Tonight, the pair is separated by about two degrees. Tomorrow night, Venus gets even closer; and Wednesday night, Venus passes atop Regulus. The difference between planet and star are easy to see. Regulus, despite its reputation as the twenty-first brightest star, is only a pinpoint of light in even the largest backyard telescopes, while Venus is clearly a partially illuminated ball. An ordinary pair of binoculars demonstrates this nicely.

By twilight's end, the southern sky is full of wonders. The appropriately named Scorpius dominates our attention. To its left, the teapot shaped constellation Sagittarius, and the southern terminus of the Milky Way, with the Great Scutum Star Cloud. This area is loaded with interesting binocular objects. The brightest star is a red star that marks the scorpion's heart, Antares. Just to Antares' right is the globular cluster, M 4. Just above the scorpion's tail, the twin clusters M 6 and M 7 are also binocular objects. This area is ideal for the binocular tourist to simply scan the skies.

Just as the sky becomes darkest, the constellation Scorpius lies due South. Scorpius is unique in that it actually looks like its namesake, the Scorpion. Scorpius is an ancient constellation and, until Roman times, included what is now Libra to form the scorpion's claws. In Greek legend, Scorpius slew Orion, the Hunter. After a titanic battle, the gods put both in the sky, at opposite ends of the heavens. The constellation's main star is Antares, "Rival of Mars." The star is named because both are red. Antares is a giant red star, 700 times larger than our Sun. It is nearing its end as it exhausts it nuclear fuel.

Tuesday, July 9th. Written by Jonathan Cassidy.

This is the darkest week of the month. A good time to view dim objects in the sky. We now have two bright stars near the top of the sky, Arcturus to the west and Vega to the east of the zenith, or top most part of the sky.

One third of the way from Arcturus to Vega is a horseshoe shaped figure called "Corona Borealis", or northern crown. Go another one third of the way, along the same line, and find a trapezoid of stars of near equal brightness. They seem dim if seen under street lights but brighter from a dark sky location. With binoculars scan the sides of this trapezoid and try to find the side nearest Arcturus. There you might see a fuzzy thing, larger than the surrounding stars and ill defined. This is M13, the brightest globular cluster visible from the mid-northern latitude.

Globular clusters are balls of 100's to 100,000's of stars that orbit our home galaxy, the Milky Way. The can be found above and below the plane of the galaxy. Temperature of the stars in a globular clusters cause scientists to think they are very old. Perhaps twice as old as our sun. This is seen in the number of red giant and white dwarf stars.

Wednesday, July 10th. Written by Ray Bogucki.

Of the five bright planets that formed the spectacular lineup in the western sky two months ago, Venus, alone, remains to dominate the evening sky. Tonight, in its continuing eastward motion through the stars, Venus passes about two Moon-widths north of Regulus, the brightest star in the Zodiac constellation Leo the Lion. Looking eastward along the plane of the ecliptic, we pass through the constellations Virgo the Virgin and Libra the Balance, before encountering Scorpius the Scorpion, low in the south. Scorpius is one of the brightest constellations of the Zodiac and one of the few in which the pattern of stars actually looks like the figure it represents.

It's interesting that Libra, the constellation to the west, was once part of Scorpius. When Julius Caesar designed his new Julian calendar, he needed one more Zodiac figure to make twelve for the twelve months. Roman astronomers solved the problem by cutting off the scorpion's claws and designating them as the new figure, Libra the Balance, which is the only inanimate object in the Zodiac. The history of this event is preserved in the delightfully mellifluous Arabic names for the two brightest stars in Libra, Zuben Eschamali (zoo-BEN ess-shah-MAH-lee) and Zuben el Genubi (zoo-BEN-el-jeh-NOO-bee) which translate into the more prosaic names, Northern Claw and Southern Claw.

The brightest star in Scorpius is the red supergiant Antares. The second brightest has been Shaula (SHAW-lah) the "Sting", at the end of the scorpion's upraised tail, but there is a new contender. Delta Scorpii (SCOR-pee-eye), the middle star in the row of three forming the scorpion's head, has doubled in brightness in the last two years and now rivals Shaula. Delta is a hot giant star which appears to be similar to Gamma in Cassiopeia. Both are rapidly rotating stars, evolving off the main sequence and occasionally throwing material from their equators. Both are in long-term outburst.

Thursday, July 11th. Written by Peter Jennes.

The Albany Area Amateur Astronomers host regular public Star Watches one weekend a month. At these events members of the club set up a variety of telescopes for guess to look through. They will be pointed at some of the brighter celestial sights, including star clusters, nebulae, galaxies, and double stars.

This coming weekend there will be Star Watches on Friday and Saturday night. The one Friday night is at the George Landis Arboretum in Esperance. The one Saturday night is at Indian Meadows Park in Glenville. Both start at 10:00 PM. They are free and open to all ages. Star Watches are canceled if the skies are mostly cloudy. For further information call 374-8460.

If you have a really clear view and low horizons in the west-northwest you have a chance to see a young crescent Moon tonight. The Moon will be less than two days past new this evening. The Sun sets at 8:35 tonight. Look for the Moon starting about one half hour after sunset, or just after 9:00 PM. The most obvious landmark in the western sky is the planet Venus, shining brightly a bit north of due west.

The crescent Moon will be to the right and below the Moon. If Venus marked the center of a clock, the Moon will be at about 4 o'clock. The distance between the two will be a bit over 21 degrees. You can gauge this distance using a fist held at arms length. The distance across the knuckles is 10 degrees, so the Moon will be a bit over two fists away from Venus. To spot the Moon you will need an obstruction free view of the western sky, and the sky must be free of clouds and haze. Your best chance for success will probably be one hour after sunset, when the sky is reasonably dark and the Moon is still a little above the horizon. If you started looking, earlier, a pair of binoculars would improve your chances of spotting the Moon.

If you miss the Moon tonight, look tomorrow night. The Moon should be quite obvious a bit less than 10 degrees to the right of Venus. You might also notice a star to the lower right of Venus on either night - it is the star Regulus, the brightest star in Leo, the Lion.

Friday, July 12th to Sunday, July 14th. Written by George Mileski

Tonight in the west about an hour after sunset, check out Venus with the star Regulus to its lower right, the waxing crescent moon lies to the right of Venus. On Saturday the moon's position has changed, it is now above and a little to the left of Venus. By midnight the summer triangle is climbing high. Vega, the main star of "Lyra the harp" is almost overhead. To the northeast lies Deneb in the middle of the milky way, a full magnitude fainter than Vega and the most prominent star of "Cygnus the swan". 

Using binoculars check out the area of sky around Deneb. If the sky is dark and transparent enough, you should be able to pick out a large area of dim nebulosity 3 degrees east of Deneb. This is NGC7000, better known as the North American Nebula, so named for its distinctive shape. The nebula spans almost three moon-widths, measures 45 light-years across and is 1600 light-years from earth. It is very dim, almost lost in this sea of stars in this region of the sky.   

If you scan down the milky way to near the southern horizon, where Scorpius the Scorpion lurks. It is in this area you'll be treated to some of the richest star fields in the night sky. Scorpius is one of the few constellations in our sky that actually looks like what its suppose to represent, a scorpion. Its main star is Antares, whose name means "rival of Mars". Next to Antares is one of the closest globular clusters in our solar system, M4 in Messier's list of sky objects. It is also one of the easiest to locate. It is 1.3 degrees west of Antares, a hazy spot using binoculars.  

West of Scorpius is the constellation Libra "the scales". Its two brightest stars are zu-ben-el-ge-nubi and zu-ben-es-cha-mali. These names come from Arabic phases meaning the southern claw and the northern claw. The stars in this constellation are rather dim. To me the the stars resemble a kite.

Monday, July 15th. Written by Joseph Slomka.

The Sun sets at 8:32, with night falling at 10:40 PM. The Moon is already up and sets just after midnight. Dawn breaks at 3:23 AM, and ends with sunrise at 5:31.

Venus is the only planet visible after sunset. It appears low in the West. Being the brightest planet, Venus appears shortly after sunset, but its low position means that atmospheric instability will mar the view. Study Venus in your binoculars and notice its phases and brightness. As Venus approaches Earth, it gets brighter and larger, but also thinner in its phase. This is due to its position between Earth and Sun.

Saturn is the only bright planet visible in pre-dawn skies. About an hour before sunrise, notice that Saturn lies directly in the path of Taurus, The Bull. Saturn appears to be in danger of being gored. The contrast of milky white Saturn and the red star Antares cannot get more dramatic.

Since the diamond-shaped constellation Libra occupies center stage tonight, a study of the constellation's history is appropriate. The constellation possesses a prehistoric identity crisis. From ancient times it is identified as the claws of the constellation Scorpius. In fact, names for the two brightest stars are Arabic for "Northern Claw" and "Southern Claw," labels that persist to this day. The other tradition associates the constellation with a balance scale. About 4000 years ago, the Spring Equinox, with equal portions of day and night, took place in that portion of the sky. The relation with a balance is obvious. Another tradition identifies the constellation with the Scales of Justice, an image we see in any county courthouse. Emperor Julius Caesar reformed the Roman legal system and the calendar. To commemorate these accomplishments, he named a month after himself (July) and instituted Libra, Latin for "scales," as a constellation. Whichever legend appeals to you, studies of constellations are fascinating for their astronomical `and cultural significance.

Tuesday, July 16th. Written by Jonathan Cassidy.

The first quarter moon glides by Spica tonight. The glow of the moon from first quarter to third quarter can make identifying the bright stars easier. This is because all the dim ones are hidden in the glare of moon glow.

The moon tonight, and this week is among several bright stars, these include: Spica, Regulus, Deneb and Arcturus. Here are the positions and how to know these stars: First go outside at night and face south, the sunset will be to your left.

Regulus will be the bright star to the west of the moon, near the sunset. Deneb will be above the path of the moon and Spica will be just below that path. Spica will be the closest bright star tonight. Arcturus is the yellowish bright star above the moon

If you know, and can find with ease, these bright stars and severl others in each season you are well on the way to navigating the night sky on your own.

The moon's position changes each night and each month. Take time during the brightest time of the moon to identify the brightest stars.

Wednesday, July 17th. Written by Ray Bogucki.

Skywatch line for Wed., July 17, 2002 Tonight, the Moon, just past first quarter, stands between Virgo and Libra and observers fret that the increasing brightness of the waxing Moon is beginning to wash out the visibility of the fainter deep sky objects. It's interesting to note that although the Moon is about 50% illuminated, it casts only about one-tenth of the light of the full Moon. This effect follows from the fact that the surface of the Moon is rather dark, with an albedo of 0.07, or approximately the reflectivity of an asphalt road. Most of the sunlight is absorbed, resulting in heating of the Moon's surface. At the current phase, the sunlight is reflected from the Moon to the Earth at about 45 degrees while at full Moon, the sunlight bounces back directly on itself to the earth. The crystalline nature of the rocks on the Moon's surface greatly enhances the reflected light at this 90 degree angle. A bit farther out in our solar system, several objects will be keeping appointments with the Sun. Jupiter will pass behind the Sun at conjunction this Friday night, followed by Mercury on Saturday night. The asteroid Vesta follows next, disappearing behind the Sun on Monday night. Vesta's orbit lies well beyond the orbit of Mars and was the fourth asteroid to be discovered, in 1807. At 538 kilometers in diameter, Vesta is the third largest asteroid known. While it is only one-half the diameter of Ceres, the first and largest asteroid discovered, Vesta is often the brightest asteroid in the night sky, occasionally reaching naked eye visibility. The honor of supplying a name for asteroids is customarily given to the discoverer. The earliest discovered asteroids were named after gods from Greek and Roman mythology. After these were used up, the names became more whimsical, including names of friends, presidents, cities, colleges, flowers, pets and even favorite desserts. Several thousand asteroids are now known and catalogued.

Thursday, July 18th. Written by Alan French.

The Moon rose at 3:06 PM this afternoon, so it will be nicely placed in the evening sky. Sunset is at 8:30 PM tonight, and one hour after sunset the Moon will be a pretty sight in the south southwest. Tonight is a good time to observe the moon.

A few features are visible even to the unaided eye. Most obvious is the terminator, the line between the light and dark portions of the moon. Right now, this is the line that shows where sunrise is occurring on the moon. The terminator is creeping very slowly to the left across the face of the moon, but within the course of one night its progress usually goes unnoticed to the naked-eye observer. If, however, you look at the Moon again tomorrow night, you should be able to see a noticeable shift of the terminator from tonight's position.

It is also quite easy to notice distinct light and dark areas on the moon. The dark areas are called maria (MAR-ee-uh) which means "seas" in Latin. Galileo and other early astronomers assumed that the maria were bodies of water. We now realize that there is no water on the moon. The maria are actually dark and relatively smooth plains caused by ancient lava flows that spread over the floors of huge impact basins.

The bright patches on the moon show us areas where mountains and craters are found. Although these highlands make the moon appear quite brilliant, the moon's surface is actually rather dark. On the average, the moon only reflects about 7% of the sunlight that falls on it. This means that the moon's surface is approximately as dark as an asphalt parking lot.

When you turn a pair of binoculars toward the moon, the view is wonderfully improved. If you can support the binoculars steadily, a few dozen craters and mountain peaks become clearly visible. Details are most obvious along the terminator. Since that is the sunrise line, objects near it cast long shadows that make them stand out in bold relief. Observing the moon with even a small telescope will reveal a wealth of detail, showing craters as small as four miles across. With a telescope, changes are plainly visible in less than half an hour as the terminator proceeds in its slow march across the face of the moon. This ever-changing vista can give anyone with even the most modest equipment a lifetime of observing pleasure.

The Moon will glide below the horizon at 1:29 AM tomorrow morning, ending our chance for lunar observing for the night but allowing the fainter stars to reveal themselves.

Friday, July 19th to Sunday, July 21st. Written by George Mileski

The moon is a waxing gibbous one, approaching Antares, the brightest star in Scorpius, the Scorpion. On Sunday the 20th, the moon will be near Sagittarius. In the west the only planet to be seen is Venus, just think, back in early May there were five planets in the western sky, now there is just one. In the morning sky at this time there is only Saturn to be seen. The distance between Venus and Regulus is increasing. Regulus in the constellation "Leo the lion", is to the lower right of Venus. 

One of the constellations you will find high in the sky at this time of the year is Hercules. It is the fifth largest constellation. To find Hercules follow the imaginary line between Arcturus and Vega, and remember that the line crosses two star patterns, the semi-circle of Corona Borealis or the Northern Crown, and the Keystone of Hercules. If you look carefully with binoculars at the Keystone, you will see a beautiful globular cluster, the most spectacular, visible from the northern hemisphere known as M13, This is supposed to be a naked eye object, I have never been able to see it myself this way. The cluster M13 probably contains 100,000 or more stars. The cluster is 21,000 light-years away. Another globular cluster in Hercules, outside of the Keystone, to the north is M92, about 25,000 light-years away.  

As far as 1st-magnitude stars are concerned, we have two enormous triangles in the sky. One is the world famous "summer triangle" of Vega, Deneb and Altair high in the east. The other is Arcturus, Spica, low in the southwest, and Antares in the south. Antares is easy to recognize with its red-ish hue, and its right in the middle of a pattern of stars, the distinctive lines of Scorpius, the Scorpion. If you look at Scorpius with binoculars, it has globular clusters, open clusters and is a great binocular study, At the bottom of Scorpius is the open clusters M6 and M7.

Monday, July 22nd. Written by Joseph Slomka.

The Sun sets tonight at 8:20, with twilight ending at 10:30 PM. Dawn breaks at 3:33 AM, and ends with Sunrise at 5:37.

As the Sun sets, Venus is the only planet visible low in the West. The planet is about two-thirds illuminated, but the brightest object in the sky except for the nearly Full Moon, located in the handle of the teapot-shaped constellation Sagittarius.

Since the Moon dominates the sky, and blots out most galaxies and star clusters, let us concentrate on Earth's satellite. Our Moon is very unusual. It is about one sixth Earth's diameter, one-sixth the gravity, and one-eightieth the mass. These facts amount to a double planet system; only Pluto's satellite, Charon, is larger in relation to the main planet. Its low gravity means that it has no atmosphere.

Thirty-three years ago, Apollo 11 landed on the Moon - the first such landing. Our ideas about the Moon changed dramatically from that moment on. We now know that the Moon is made mostly of light rocks.

Before Apollo 11, most scientists thought that the craters were old volcanoes. The only certainty is that the Moon, early in its history, underwent a severe history of bombardment, leaving behind craters that binoculars can see. This led to a reexamination of Earth history and the realization that large space rocks hit Earth in the past, and could do again in the future.

Despite the fact that the Moon was visited several times by astronauts and is only two light seconds away, we know remarkably little about its history and composition. There are three competing theories. One is that the Moon formed the same time as Earth, with the two bodies orbiting about a common axis. A second hypothesis is that the Moon is a body that accidentally wandered into Earth's gravity field and was captured. The prevailing theory is the Moon formed after a Mars-sized body sideswiped Earth, and knocked off a layer of crust. It rapidly coalesced into the body we see nightly. If this third option is correct, it explains many oddities about the Earth-Moon relationship.

Tuesday, July 23rd. Written by Jonathan Cassidy.

Full moon this week so the night sky will not be too dark. There is one group of stars that we should look for tonight and tomorrow.

To the south is a bright reddish star called Antares. It is the brightest and reddest of all the star in that region. Next you will see the near full rising moon. Near to the rising moon you will pick out a group of stars that resemble a teapot. This asterism is as large as your hand at arms length. In dark sky conditions there are too many other stars to make out the teapot with ease. Tonight it is easier because the light of the full moon makes the smallest stars invisible.

Knowing where the Teapot is can help us navigate through the Milky Way Galaxy on dark sky nights. The Teapot is part of the constellation Sagittarius. This constellation in some cultures is seen as a centur archer. The spout rises first, with an equilateral triangle of stars marking the top following and the stars of the handle coming up last.

If you find the teapot tonight try it on a dark moonless night in a dark place. When it is dark out we can see smoke rising from the spout of the teapot. This is the center of the milkyway galaxy. The rest of the galaxy extends up the sky toward Cygnus the swan.

Wednesday, July 24th. Written by Ray Bogucki.

Skywatch line for Wed., July 24, 2002 Three of the bright planets, Mercury, Mars and Jupiter, are too close to the Sun for useful viewing. Venus still shines low in the west, but it sets just about the time that evening twilight ends. Saturn, close to the southern horn of Taurus the Bull, now rises at 3 a.m., about an hour before the onset of morning twilight, so it presents good viewing for early risers. About 4 a.m. tomorrow, Saturn will be about 10 degrees above the horizon and very close to the famous Crab Nebula, the expanding remains of a supernova that blew itself apart in the year 1054 AD In fact, Saturn's brightest moon, Titan, will be transiting across the nebula. The two planets that are most conveniently placed for observation in the late evening are the more distant gas giants, Uranus and Neptune. Neptune is in Capricornus while Uranus is on the Aquarius-Capricornus boundary. Tonight, the Moon is full and passing just 4 degrees south of Neptune. Tomorrow night it passes about 4 degrees south of Uranus, which is just at the edge of naked-eye visibility, although the brightness of the Moon will necessitate the use of binoculars and a sky atlas to find the planet. Uranus is always a pretty sight in a small telescope, its pale blue-green disk shining steadily in contrast to the nearby twinkling stars. The color is caused by the large amounts of methane in its atmosphere. It is interesting to note that currently, the disk of Uranus appears just the same size as the disk of Mars. The actual radius of Uranus is about 7 times larger than the radius of Mars, but by coincidence, Uranus is currently about 7 times farther away than Mars. Even though their disks are both about 3.7 arc-seconds, Mars shines 40 times brighter than Uranus. This happens because, while sunlight falling on Mars is about one-half the intensity of sunlight on the Earth, sunlight striking Uranus is 400 times fainter. In fact, an observer on the frozen world of Uranus would see the Sun only as a very bright star, shrunken in diameter down to a little larger than Jupiter appears to us.

Thursday, July 25th. Written by Alan French.

The Moon was full during the morning hours this past Wednesday, so it will be somewhat over a day past Full when it rises tonight. Moonrise is at 9:40 PM tonight, so a very bright gibbous Moon will dominate tonight's sky.

The orbit of the International Space Station, or ISS as it is often known, often takes it over our area. Sometimes is passes directly overhead, and sometimes it is not far above the horizon. Tonight you can see the ISS not once, but twice as it travels high above the Capital District. After the Sun sets we are down in the relative darkness of the Earth's shadow, but the ISS is still up where the Sun is shining, and the reflected sunlight makes the Space Station easily visible to the unaided eye.

During the first visible pass, the ISS will not be far above the horizon. It will first appear just after 9:15 PM above the southern horizon. It will be highest just before 9:18 when it will be 22 degrees above the southeastern horizon. Simply look for a reasonably bright star moving along the southeastern horizon after 9:17 PM. The ISS will vanish above the northeastern horizon just after 9:20 PM.

On its second pass, the ISS will be higher in the sky. It will make its first appearance above the west-southwestern sky at 10:51 PM. It will be highest just before 10:54 PM when it will be 45 degrees above the north-northwestern horizonm and will vanish below the northeastern horizon a bit before 9:57.

Satellites are often a bit difficult to spot when they first come above the horizon, and are easiest to spot them as they approach their highest point.

The Albany Area Amateur Astronomers will hold a public Star Watch in the Pine Bush beginning at 9:30 PM on Friday night, July 26. A variety of telescopes will provide views of the night sky and their will also be a constellation program. Look for the reflective "Star Watch" sign at 1250 Kings Road. Star Watches are free and open to all ages. The program is canceled if the skies are mostly cloudy.

Friday, July 26th to Sunday, July 28th. Written by George Mileski

The moon on Friday the 26th of July is a waning gibbous moon. The planet Uranus lies 4 degrees north of the moon and is visible in binoculars but a finder chart from the April issue of Sky and Telescope on pages 94 and 95 will help locate it. The planet Venus is the beacon in the west, with the star Denebola to the upper right. Denebola is the tail of the constellation " Leo the lion". The planet Venus has phases as our moon, right now it has a gibbous phase or about 60% or so illuminated. 

Again this is visible in binoculars. Try looking before the sky gets to dark, if you have a telescope, use it instead. 

South of the constellation Hercules you will come to a large five-sided pattern of stars in the constellation Ophiuchus. The constellation was known to the ancient peoples as the Serpent Bearer, but nowdays no one sees a person holding a snake. Instead some people call it the coffin, because to them it looks like a large box. The brightest star in the constellation, Alpha Ophiuchi or Ras Alhague, is the one shown at the point formed by the star pattern at the left side of the constellation. Extending out both sides of Ophiuchus are parts of the constellation called Serpens, the serpent or snake. This is the only constellation that is broken into two parts. The head of the snake, Serpens Caput, has a row of stars extending upward from Ophiuchus toward Corona Borealis.  

The snake's tail Serpens Cauda, extends downward from the southern part of Ophiuchus toward the constellation Aquila. The upper part of Serpens contains a well-known globular cluster of stars called M5 which can easily be seen in a small telescope. There are three other globular clusters M10, M12 and M14.  

Southeast of Ophiuchus is the constellation Sagittarius shaped like a teapot. For now the only thing I will say for this area of sky is to sit down in a lawn chair with a pair of binoculars and take in the sights of globular clusters, open clusters and nebulas. This is a fantastic part of the sky to observe just using binoculars.   

Monday, July 29th. Written by Joseph Slomka.

The Sun sets at 8:19, with night falling at 10:18 PM. Dawn breaks at 3:40 AM, with sunrise at 5:44.

As the sky darkens, only Venus is visible in the West, it is about 20 degrees high, and sets about an hour and a half after the Sun. In binoculars or telescope, it appears about sixty percent illuminated.

Dawn is becoming interesting. Saturn is high in the East, while Jupiter is peeking above the horizon. Trees or hills may hide Jupiter. As time passes, Jupiter will become easier to see.

Below the constellation Pisces is the constellation Cetus, the Whale. One of its stars is Omicron, also called Mira. Mira is a variable star, which means that it periodically brightens and dims. Mira goes from ninth magnitude to third, or even brighter, in about 331 days. When astronomers first discovered this star, they called it "mira," meaning "wonderful". Mira is an old red star, nearing the end of its life, about 420 light years away and about 900 times larger than our Sun. In other words, if substituted for the Sun, Mira would reach to Jupiter. However, weighing in at a few solar masses, Mira is a virtual vacuum. Mira's variations are due to pulsations from processes deep within the star. Mira will peak in late July or early August. If you are up at or before dawn, look to the southeast. You will see the Great Square of Pegasus. Below, Pegasus is a fainter chain of stars that form the constellation Pisces. Pisces forms a "V" shape, pointing to the horizon. Below that "V" is part of Cetus that contains Mira. Look for a gradually brightening star. It will reach maximum, then turn red, and gradually dim. Since Mira dims earlier each year, this is one of last chances for you to observe Mira's cycles before the dawn and sunrise wash it out. The next chance may be the year 2007!

Tuesday, July 30th. Written by Jonathan Cassidy.

Find due east tomorrow morning. We have the return of Orion to the night sky Wednesday morning. The belt of Orion stand vertically above a point due east. This is good to note for astronomical navigation purposes.

To find our way around the sky to locate any object you will need to know where north south east and west are. Orion on the horizon gives us in the mid norther lattitudes an accurate east direction with out the need for instruments.

Once you establish the direction of east you can find north, south and west. Next night watch the center of our galaxy rise in the south east after Antares. You will not see this on a night with the moon up. See that near the horizon there is an asterism of stars that looks like a teapot. Find the spout and see the milkyway galaxy rising out of that spout like steam Notice how the galaxy extends up toward the bright triangle of stars we call the summer triangle.

Because Antares and the teapot are near the horizon they are not visible for long. Soon they set in the south west.

Wednesday, July 31st. Written by Mike Molitor.

Tonight Venus is the 'evening star'. Look for Venus in the west during twilight. It is dazzling at magnitude &endash;4.2 (minus 4.2). A small telescope should show Venus 60% illuminated, similar to the waning gibbous Moon tonight.

Two other planets are in the night sky, Uranus (magnitude 5.7) and Neptune (magnitude 7.8). Viewing these far away 'gas giants' is best done with a telescope and a good locator map. This summer they are a maximum of only 30 degrees above the southern horizon, making the viewing very challenging.

Mid-summer nights are best for experiencing the glory of the Milky Way. This time of year it stretches directly overhead from north to south. It is best to view from an open field, well away from the city and with no local lights. Recline in a comfortable chair, or lie in a sleeping-bag or on a blanket, and using just your eyes, experience the full expanse of the Milky Way. Add binoculars, and you can get lost among the star clouds and dust lanes of our own galaxy!

While viewing the Milky Way, be on the look-out for meteors. The delta-Aquarid meteor shower was at its peak rate on Monday, but a few meteors may still streak through our atmosphere for several nights either side of the peak. The radiant of the shower rises above our horizon around 11pm. The delta-Aquarid meteors are not as impressive as mid-August’s Perseid or November’s Leonid meteor showers, but it is always good to be on the look-out when any meteor shower is in-progress. Random fluctuations in the quantity of dust particles in the meteor stream can cause the number of visible meteors to increase dramatically.

The Moon rises at midnight tonight and its light will wash away the faint glories of the summer Milky Way, as well as the chance to view meteors.

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Dudley Observatory
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Schenectady, NY 12308
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