Skywatch May 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.

Wednesday, May 1st. Written by Ray Bogucki.

The tightening alignment of the five bright planets continues to provide a fascinating show in the western evening sky. The lowest two planets, Venus and Mercury, continue to climb higher towards Saturn and Mars, which are already a close pair. Saturday night, Mercury will reach its farthest eastern elongation from the Sun and will begin to turn back toward the Sun. At this time, a telescope will show Mercury appearing one-half illuminated like a tiny, first quarter Moon. Venus will continue moving eastward until it meets and forms a compact triangle with the Saturn-Mars pair this weekend. All three planets will be easily visible together in a single binocular field - a spectacular sight! Venus will then pass extremely close to Mars a week later, and eventually pass close to Jupiter early in June.

For early risers, the Earth will put on a different kind of show as it now begins to pass through the broad cloud of debris left in Earth's orbit by Halley's Comet, giving rise to the meteor shower known as the eta-Aquarids. This shower should reach maximum rates early Sunday morning. Because the constellation Aquarius, which contains the radiant for this shower does not rise until about 3 a.m., the meteors are best observed after that time, in the hour or so before the beginning of morning twilight. The Moon will be one day past last quarter and will rise about the same time as Aquarius, causing some interference with the observation of the fainter meteors. Nevertheless, this is a dependable shower with a larger number of meteors than most. Aquarids are fast meteors, moving at 65 kilometers per second and often leaving persistent trains.

Thursday, May 2nd. Written by Peter Jennes.

On Tuesday, NASA released the first images from the refurbished Hubble Space Telescope. During the servicing mission, astronauts replaced solar panels and the power control unit, and also installed an exotic cooler for the infrared camera. While those installations were critically needed, replacing the Widefield and Planetary Camera was the main objective of the mission. Although the Widefield camera provided a wealth of discoveries and memorable images like the Pillars of Creation and the Hubble Deep Field, the aging camera was ready for retirement.

Despite the Widefield Camera’s impressive legacy, technological advances enabled the creation of a far more sensitive instrument. The new camera, called the Advanced Camera for Surveys or ACS, has twice the field of view and twice the resolution of the old Widefield camera. In fact, the first images from the ACS show detail similar to the Hubble Deep Field from an exposure that took less than one-tenth the time. Using the improved resolution of the new Survey Camera, astronomers believe they will be able to image galaxies as they appeared less than one billion years after the Big Bang. In addition, the wider field of view of the ACS will enable astronomers to map galaxy associations and the large-scale structure of the universe with greater detail than ever before.

Although you won’t see Hubble-like detail, a small telescope can sample the large-scale structure researchers are working on. Starting with our own galaxy, the Milky Way belongs to the Local Cluster of galaxies. This small cluster is made up of dwarf elliptical galaxies that are almost impossible to see and monster spiral galaxies like the Andromeda and Pinwheel Galaxies that are visible in binoculars. Moving further out, the next galaxy cluster is the Virgo Cluster. Several members of this cluster are visible through small telescopes near the tail of Leo. Our own Local Cluster is an outlying member of the Virgo Cluster and when all the members are put together, they form the Virgo Supercluster of Galaxies. Continuing outward, additional galaxy clusters dot the sky and join together like chains strung across the sky. Using the refurbished Hubble to study these structures, astronomers hope to learn more about the dark matter that binds the clusters and the dark energy that accelerates their spread.

Friday, May 3rd to Sunday, May 5th. Written by George Mileski

Of all the objects in the sky at this time the ones that stand out the most are in the western part of the sky. They are of course the five planets, Jupiter, Saturn, Mars, Venus, and Mercury. This is the month to see them because at the end of this month two of them will be below the horizon, that is Mercury and Saturn. That leaves us with Venus, Jupiter and Mars that can still be seen at the end of this month. On Friday the triangle of planets, Saturn, Mars and Venus keeps getting tighter, they will be about four degrees apart with Mercury below and to the right of them. The next few nights will bring them even closer together.

Below Mercury is the open cluster the "Pleiades" also called the "seven sisters". When this group is higher in the sky its a great binocular object. West of the triangle of the planets is Aldebaron the brightest star in the constellation Taurus. It represents the eye of the bull for that constellation. Jupiter lies further east of the planet triangle. By Sunday the five planets will span 36 degrees, it should be a great sight and the weather forcast is favorable.    

Some other interesting binocular sights are "Berenice's Hair" in the constellation "Coma Berenice". Its small and very faint and is located between the constellation "Leo the Lion" and "Bootes". It contains a group of stars that are somewhat shaped like the letter "Y" which points north to the big dipper. Another interesting site is the star cluster, the Beehive or M44 the Messier catalog number, in the constellation Cancer. This is located between the star Regulus in Leo the Lion and Pollux in Gemini.  

The moon reaches last quarter on Saturday, it rises at 2:43AM. The meteor shower called "Eta Aquarid", occurs anytime in the early morning from 3AM till dawn from May 4th thru the 6th. The radiant lies near the water-jar asterism in Aquarius looking east. Comet Ikeya-Zhang can be seen before sunrise between the constellations Cepheus and Draco, heading for Draco. It is getting harder to see, its about a magnitude 5 or so.  

Monday, May 6th. Written by Joseph Slomka.

As the sky darkens, the alignment of bright planets continues. However, all the participants are located lower each day, and frequently switch positions. Jupiter is still highest in the southwest. Mars, Saturn and Venus form a tight triangle. Venus is the brightest, and will be the first to break through the twilight. The three planets should occupy the same binocular or low power telescope view, since each is about two and a half degrees from its neighbors. Elusive Mercury is to this group's lower right, about eighteen degrees above the horizon. Finally, the pretty star cluster, the Pleiades, finishes off the line, seven degrees to Mercury's lower right, just above the horizon. By twilight's end, only Mercury and the Pleiades dip below the horizon. The other planets hover low over the western horizon.

Pre-dawn observers can still find comet Ikeya-Zhang in the head of Draco, the Dragon. The comet is now fading, as it heads out into the cold, distant reaches of the Solar System.

If an observer looks north tonight, he will see a long chain of stars between the Big and Little Dippers. This chain ends with a small rectangle pointing at Hercules. This is the constellation Draco, the Dragon. Draco is important for several historical reasons. One of its stars, Thuban, was the pole star about 2830 BC. There is speculation that ancient Egyptians used Thuban as a reference point in building the great pyramids. There is no specific mention of Draco in any Greek legend, and the origin of this constellation seems lost. However, this large constellation makes a fitting guardian of the North Pole. Draco was originally pictured as a true dragon, with wings sprouting from its midsection. Draco's wings were clipped around 600 BC, and reshaped into a new constellation, Ursa Minor, the Little Dipper. Its brightest star, Gamma Draconis, is slowly approaching our Solar System. In a million and a half years, Gamma will be a bright as Sirius is today.

Tuesday, May 7th. Written by Jonathan Cassidy.

We have a planetary night tonight. Look in the west after sunset this week and find Venus, Mars and Saturn making a nice compact triangle of less than 3 degrees, less than the width of two fingers at arms length. Below this group is elusive Mercury and above the group is Jupiter.

Though the planets are near each other this week they are going in different directions:

Mercury is speeding by of us, Venus is catching up to us. Mars, Jupiter and Saturn are falling behind our position in the solar system.

This relative motion brings the planets together in our sky and takes them apart from each other. It is an ever changing senario that defeats the old earth or sun centered concept of the universe.

Watch this group over the time of this month and see them change position at what seems to be different rates of speed. The different apparent speeds are due to their position relative to us and the Sun. The inner planets always seem to be going fast while the outer ones seem to wander slowly.

Wednesday, May 8th. Written by Ray Bogucki.

Perhaps the best known star pattern in the northern hemisphere is the Big Dipper, part of the constellation Ursa Major, the Great Bear. The Big Dipper is currently almost directly overhead in the evening sky. For centuries, the most utilitarian function of the Big Dipper was to provide the two stars at the end of the bowl of the dipper as "pointer stars" for Polaris, the star that marks the northern pole of the Earth's rotational axis. Polaris resides in the constellation, Ursa Minor, the Little Bear, whose major pattern is known as the Little Dipper. Because its stars are much fainter than those in the Big Dipper, the Little Dipper is about as little known as the Big Dipper is well known. Nevertheless, the bowl of the Little Dipper also serves a utilitarian purpose. The magnitudes of the four bowl stars of the Little Dipper are roughly 2, 3, 4 and 5. Thus, a quick glance at the bowl stars allows amateur astronomers to gauge the darkness, clarity and transparency of the night sky. If the fifth magnitude star in the bowl is clearly visible to the eye, it should be a good night for sky watching.

Polaris, at the end of the handle of the Little Dipper, is a large star, about 3500 times more luminous than the Sun, but its distance of 430 light-years reduces its brilliance to second magnitude. For centuries, Polaris has been used by mariners and travelers as a guide star. Its position is very close to true north while its distance in degrees above the northern horizon is a measure of the observer's northern latitude. This has not always been the case. Because Earth's axis of rotation is tilted 23.5 degrees from perpendicular to the plane of our orbit around the Sun, gravitational pulls by the Sun and Moon on the Earth's equatorial bulge cause a slow precession or "wobble" of our rotational axis. Once in every 26,000-year cycle, the Earth's rotational axis sweeps out a conical shape while the extension of our northern axis traces a circle in the sky with a 47-degree diameter. Forty-six hundred years ago, during the ancient Egyptian period of pyramid building, the north-marking star was Thuban, in Draco, the Dragon. Fourteen thousand years from now, the brilliant star, Vega, will be close to the northern pole.

Thursday, May 9th. Written by Peter Jennes.

The moon is now a slender crescent in the predawn sky and that makes tonight ideal for star hopping practice. Amateur astronomers use star hopping as a way to find dim stars by moving from bright stars to dimmer target stars. However, before you begin star hopping, make sure to look Mars and Venus in the west. Tonight, these two planets are about one-half degree apart and by tomorrow night, they will be almost twice as close.

The dim stars of Virgo are good targets for beginning star hoppers. At first magnitude, Spica is the brightest star in Virgo and will act as our starting point. Star hop to Spica by starting with the Big Dipper's bowl and follow the curved handle away from the dipper to the first bright star you see. This is Arcturus, the brightest star in the Bootes and the third brightest star in the sky. By finding this star, you have followed a star hopper's mnemonic, "arc to Arcturus."

From Arcturus, use another mnemonic to find Spica. This one is stated, speed south to Spica. That is, a line drawn south from Arcturus leads to Spica. By following the saying, arc to Arcturus, speed south to Spica, you have found the sky's sixteenth brightest star by using the sky's third brightest star.

From Spica, you can begin tracing the dimmer parts of Virgo. The brightest sections of Virgo occupy a fifteen degree patch of sky stretching west from Spica. Use Spica as the lower left corner of an imperfect rectangle that is tipped upwards on its west end. Three, third magnitude stars make up the other corners of this rectangle. This starry rectangle is longer east to west than it is north to south.

Now, use the two most western stars of the rectangle as pointer stars. Draw a line north from these two stars. Extend this line about one and one half times the distance between the two stars. In that region of space, you will find another third magnitude star. This star is Epsilon Virgo, otherwise known as Vindamiatrix. Having found these stars, you have outlined most of a somewhat dim constellation. With a star atlas and a little more star hopping, you should be able to find the remainder of this famous springtime constellation.

Friday, May 10th to Sunday, May 12th. Written by George Mileski

Have you ever noticed how the moon appears larger when its near the horizon than when its overhead, I think we all have. The difference is so apparent, it seems impossible that its not real. Yet how could this be? The moon is no closer to us on the horizon than it is overhead. You get the same effect with the sun. It seems enormus as it dips below the horizon. The moon illusion or horizon illusion as it is sometimes called was recognized as an enigma as long as 350 B.C., when Aristotle incorrectly attributed it to atmospheric "vapors" that distort images close to the horizon. Around the year 1000, Arabian physicist Ibn Alhazan offered the explanation we use today. He suggested that a familiar background such as distant trees or houses, provides a frame of reference not available when the moon is overhead. 

Since the moon looks huge by comparison with these familiar objects, the mind insists that it is vast in size. This theory sounds plausible but is fails to explain why the same effect occurs with a perfectly flat desert or ocean horizon. Somehow looking up has something to do with the illusion. As a test, volunteers were put in a dark room with a disk straight ahead and an identical disk at the same distance overhead. Again everyone thought that the overhead disk was smaller. So apparently two factors are involved: (1) association with the distant horizon and (2) looking straight ahead as opposed to looking nearly overhead. Yet there is more to it than that. But nobody is sure just what it is. It is one of the most powerful illusions in nature. 

The night sky for Friday finds the bright planet Jupiter in the west, with Venus and Mars to the lower right of it, they are less than a degree apart, the closest they will get to each other. Saturn is directly below Venus, and Mercury is to the right and below Saturn. On Sunday the moon will be new. The comet Ikeya-Zhang is located in the constellation Hercules. Its getting dimmer, about a magnitude 6, so you need binoculars or a telescope to see it. It can be seen about 10:00PM or so in the N.E.

Monday, May 13th. Written by Joseph Slomka.

The Sun sets tonight at 8:09 PM. Night falls two hours later. Dawn breaks at 3:36 AM and ends with sunrise at 5:34.

The planetary alignment is now breaking up. Jupiter remains highest, but only halfway up the sky. Twenty degrees to Jupiter's lower right, Venus and Mars are bunched up. Both are within a two degrees of each other, easily fitting into the same binocular view. Venus is the brightest object in the sky; in telescopes it appears about eighty-six percent illuminated. Mars is visibly dimmer than Venus. Saturn, Mercury, and the Moon form another tight group about seventeen degrees above the horizon. Again, all three should fit into the same wide binocular field. Saturn is the brightest; Mercury is a bit below, and dimmer.

The Moon is less than one day old and forms a very thin crescent, only two percent illuminated. Binoculars may be necessary to pick out this very young Moon. Can you spot it? Some astronomers have informal contests to spot the youngest Moon. Some religions rely upon sightings of the thin crescent to mark the new month's beginning.

After nightfall, Comet Ikeya-Zhang now occupies the constellation Hercules. The comet is about five degrees above M-13, the famous star cluster. Both should be observed in binoculars. The comet is now receding into the outer Solar System, and rapidly dimming.

Tuesday, May 14th. Written by Jonathan Cassidy.

Ursa Major, the great bear, is at the zenith this month. We see this constellation's brightest stars as the asterism called "the big dipper". The dipper makes up the tail and body of the bear. Dimmer stars can be traced to make the head and legs.

Seeing a bear in this area of the sky has been a common legend among many diverse cultures. The American Natives sew three hunters chasing a bear, and the middle hunter carried a cooking pot. This can be seen as the middle star of the dipper's handle which has a small companion star.

Peoples of Greece and central and easters Asia also saw a bear. However they all had different myths associated with the same general group of stars.

The Big Dipper is circumpolar. That is is revolves around the pole star and never sets below the horizon. In the spring the bowl seems upside down this has been seen as the dipper pouring water on the spring crops. As the Dipper goes around the Sun it dips to the horizon and picks up water, seen in the autums of each year, later to dump its load in the spring.

Wednesday, May 15th. Written by Ray Bogucki.

Tonight, all of the bright objects in our solar system are strung out in a 48-degree arc, spanning from the Sun to Jupiter. With Venus moving rapidly eastward the order now stands with Mercury lowest, followed by Saturn, Mars, Venus and Jupiter. The Moon has also joined the line standing next to Mercury very low in the twilight last Monday. Last night it passed within a degree of Venus and tonight it stands about two-thirds of the way from Venus to Jupiter. In fact, in a rare event yesterday, the Moon actually occulted Saturn, Mars and Venus in quick succession, as seen from different locations on the Earth.

Mercury, swinging rapidly toward the Earth, will be the first planet to disappear from the lineup, as it drops quickly back towards the Sun and is lost in the glare. It will pass between the Earth and Sun, at inferior conjunction, in 12 days. By month's end, Saturn will also disappear into the bright twilight. The Earth's orbital motion will cause Saturn to pass behind the Sun in early June.

Meanwhile, Venus will continue its movement toward Jupiter. It will pass close to Jupiter in early June and during the entire first week of June, we will witness a spectacular pairing of our two brightest planets low in the west. By late June, both Jupiter and Mars will disappear into the glare of the setting Sun and Venus will reign alone as the evening star.

Even as Mars and Jupiter are disappearing in the evening twilight, however, the planetary show will continue as Saturn and Mercury reappear in the early morning sky. On July 2, the innermost and outermost of the naked-eye planets will shine together in the early morning twilight, low in the east-northeast within half-a-moon width's distance of each other. This means that the two planetary disks will easily be visible side-by-side even in the narrow field of a moderate-sized telescope -- a rare sight.

Thursday, May 16th. Written by Peter Jennes.

The six-day-old crescent Moon will be in the southwest at sunset. At this age, the Moon’s Southern Hemisphere is just beginning to reveal its rugged highland terrain. The southern highlands are covered with craters that testify to the massive bombardment the early solar system underwent from swarms of meteors. By comparing the cratered south with the smooth maria visible to the north, you can sense the contrasting geologic forces that have shaped the moon. The energy released by impacts and eruptions are frozen in time and available for detailed inspection on the Moon.

In observing craters, you will see that some of them have central mountain peaks. These mountains are the frozen splashes of lunar debris that was tossed up during the impact. To get an idea of the energy released on impact, you need to realize that some of those splashes are thousands of feet high and the basin they formed in average ten to sixty miles in diameter. Putting this another way, picture a hole stretching from Utica to Amsterdam and having several of the High Peaks nestled inside.

The most prominent maria on tonight’s moon will be Mare Crisium or the Sea of Crises. The Sea of Crises is nearly circular and has a dark, smooth floor. The north-south diameter of this lunar sea is almost 280 miles while the east-west diameter is almost 350 miles. This makes the Sea of Crises about equal in area to the state of Washington. Like all maria, the floor of the Sea of Crises is vast lava plain that formed from volcanic eruptions billions of years ago.

South of the Sea of Crises, a portion of another lunar sea, the Sea of Fertility is visible. With a telescope, several major craters are visible around the western edge of the Fertility basin. This chain of craters includes Langrenus, Vendelinus, and Petavius. Langrenus is nearly 90 miles in diameter and it has an unusually small central peak. Vendelinus is slightly larger than Langrenus but more difficult to spot because it is flooded by lava. The final crater, Petavius is over 100 miles in diameter and nearly 14,000 feet deep. The floor of this ancient crater displays an entire mountain chain with peaks rising over 8,000 feet above the crater’s floor.

Friday, May 17th to Sunday, May 19th. Written by George Mileski

Venus as everyone knows is the brightest planet in the sky, in fact its so bright it can be seen in the middle of the day with the naked eye, if and I mean a big if, you know where to look. Before Venus can be located in the daytime sky, a preliminary sighting in a dark evening sky will establish its general location. Try to catch Venus as soon as the sky darkens after sunset. Once you spot it, try to mark its position with a straight line through the top of a telephone pole, a chimmey or anything that projects into the sky. The next night stand in the same location and look for Venus earlier in the evening slightly above and to the left of the marked position.  

Venus appears to move the width of a thumb, held at arm's length, and thats roughly two degrees in eight minutes. This is not Venus's motion but earths rotation. Therefore, if Venus was previously observed 15 minutes after sunset, search the sky right at sunset, two outstretched thumb widths, roughly four degrees above and to the left of the marked position. Keep backing up in this manner until Venus is viewed well before sunset. By using this method its easy to find Venus in a clear blue sky, an hour or more before sunset.  

Another guide to Venus during the day is to follow the crescent moon. At certain times of the month the moon will be positioned near Venus. You can find out what days this is by using the " Abrams Planetarium" sky calendar or "Sky and Telescope" magazine and there are other astronomy publications and calendars to use for this. 

Binoculars are very helpful when looking for Venus during the day, but you should block the sun by standing at the side of a building or something so you don't accidently look at it with the binoculars, just to be safe. Once your eyes are focused on Venus during the day you'll wonder why you never saw it before. I have also seen Jupiter during the day, again using the moon as a guide for it. Its not easy to see, you need binoculars, better yet a telescope.  

In the western part of the sky the winter constellations will soon be leaving us, that is Orion, Gemini, and Auriga. The moon will be at first quarter on Sunday the 19th of May in the constellation Leo the Lion. The highlight in the west is of course the lineup of planets. The comet Ikeya-Zhang is found in the constellation Hercules. It is strictly a binocular or telescope object, it keeps on getting further away and dimmer. It will move into the constellation Corona Borealis on Sunday.    

Monday, May 20th. Written by Joseph Slomka.

The Sun sets tonight at 8:16; the sky becomes darkest at 10:19 PM. Dawn breaks at 3:24 AM, and ends with sunrise at 5:27.

The planetary alignment is now breaking up. Jupiter is still the highest planet, but is now less than halfway between horizon and zenith. Venus is the brightest object in the sky and lies about 13 degrees below and to Jupiter's right. Mars follows, but is very difficult to spot because of its small size, inherent darkness, and low altitude. Mercury follows Saturn. Mercury is only six degrees above the horizon, and becoming lower each day. Mercury soon departs our skies, hides behind the Sun, and reappears in evening skies.

The Moon passed First Quarter yesterday, meaning that the Moon is located almost due South by sunset. It also means that dim objects, like Comet Ikeya-Zhang in Hercules, will probably be washed out by the reflected sunshine.

As twilight ends, the constellation Bootes rides high in the eastern sky. The constellation is kite-shaped and trails behind Leo. The Greek word Bootes refers to a "herder" or "driver". However ancient legend is not clear whether Bootes is driving cattle or the Great Bear, Ursa Major. Arcturus is the Lucida, the brightest star in the constellation. The origin of the word Arcturus is shrouded in mystery, but is apparently one of the first stars to be named. Its rising was feared by sailors, for it forecast the stormy spring season, but anticipated by farmers for the same reason. Arcturus is 37 light years away and one of the brightest stars in the sky. It is a giant reddish yellow star, twenty million miles in diameter, 115 times the Sun's brightness, but only four times our Sun's mass. In other words, Arcturus is a giant shell, which is cooling down. Its surface temperature is only 4200 degrees Kelvin, quite cool for a star. Arcturus travels at a very high speed. It will approach our solar system in a couple thousand years and then speed rapidly away into the cold, dark reaches of space.

Tuesday, May 21st. Written by Jonathan Cassidy.

We have gibbous moon tonight. The light from the moon is brighter each night. This brightness wipes out our view of dim objects in the night sky. Let us look at the brighter stars to help us navigate around the sky at night.

The big dipper stand out no matter how bright the moon is so let us star there. We all know that the stars at the far end of the bowl pount north roughly to Polaris, the star nearest the geographic north pole. In the other direction these same two stars point at the constellation Leo, the lion. While the two stars at the handle end of the bowl point at Regulus, the brightest star in Leo.

The arc of the handle can be followed out to find Arcturus, the bright star in the same arcing path. Thus giving us one of our best sayings to aid our navigation "Arc to Arcturus". Then from Arcturus "Speed on to Spica" the next brightest star, this in the constellaiton Virgo, near the horizon.

The east most bowl star and the next two handle stars line up to point to Hercules and to the particular region of that constellation where you can find M13. M13 is the brightest globular cluster seen from the norther hemisphere. It can be found with binoculars.

Wednesday, May 22nd. Written by Ray Bogucki.

Tonight, at nightfall, the Big Dipper flies high overhead in the northern sky, its two outer bowl stars pointing faithfully at Polaris, the North Star. If you turn 180 degrees and face due south, you will find that Polaris has a southern counterpart at this time of year. Shining in the south, just a little lower in altitude than Polaris is the bright star, Spica, in the Zodiac constellation, Virgo, the Virgin. Spica is easily identified tonight because it lies just below and a bit to the left of the waxing, gibbous Moon. Located just a few degrees off the ecliptic, Spica is occasionally occulted by the Moon.

With a diameter eleven times larger than, and a mass eleven times greater than our Sun, Spica is a magnificent blue-white giant. Spectroscopic studies show that Spica has a companion star six times larger than the Sun, and that both stars orbit their common center of gravity once every four days at the amazing distance of only eleven million miles, too close to be split by any ordinary telescope. Their combined luminosity is more than 2000 times that of our Sun, and even though they lie at the significant distance of 260 light-years, their combined light reaches us with a brightness that makes Spica a first-magnitude star.

Halfway along a line from Spica to the bowl of the Big Dipper lies a very close open star cluster, in the constellation, Coma Berenices (KO-mah BEH-re-NYE-seez). Lying at about the same distance away as Spica, this is a true cluster with all its stars born at the same time from the same cosmic cloud of gas and dust. The dozen or so visual stars are fainter and more spread out than those in the better-known Pleiades. The cluster was more familiar in times past when skies were darker, but it still presents a splendid sight from a dark sky location. The view in binoculars is breathtaking. The author, G.P. Serviss described the cluster as .." a curious twinkling, as if gossamers spangled with dewdrops were entangled there. One might think the old woman of the nursery rhyme who went to sweep the cobwebs out of the sky had skipped this corner, or else that its delicate beauty had preserved it even from her housewifely instinct..."

Thursday, May 23rd. Written by Peter Jennes.

Tonight, an eleven-day gibbous moon hangs low in the southeast at sunset. Along the terminator, the contrast between darkness and light allow lunar features to stand out in great relief. Elevated features cast shadows that make minor rises appear as massive mountains. Lips of craters near the terminator gleam in sunlight while their interiors lie trapped in blackness. Tonight, lighting conditions for seeing these effects are at their best in the southwest quadrant of the Moon. Some of the Moon's most unusual craters are located in this quadrant so it will be worthwhile to spend time exploring this region with your telescope tonight.

If you follow the terminator down until you are near the southwest limb of the Moon, you will come to Schickard, a large crater with its western edge exactly on the terminator tonight. Schickard is about 140 miles in diameter and nearly two miles deep. Because of its size and because the crater floor appears to be relatively smooth, Schickard is called a walled plain. In fact, Schickard is one of the largest walled plains on the moon. The floor of Schickard and the floors of other walled plains appear smooth because their interiors are flooded with ancient lava flows. However, unlike other walled plains the floor of Schickard is domed upward and if you were standing in the center of the crater, you might not be able to see the crater walls. Through a telescope, the interior of Schickard displays dark, lunar mare like coloration while the central section is light colored like the rest of the lunar highlands.

Friday, May 24th to Sunday, May 26th. Written by George Mileski

When you step outside and look at the night sky, there is more than just stars, planets and the moon in the sky. You will see pulsating aircraft lights, the flash of meteors, which are bits of cosmic debris entering the earth's atmosphere. There are other moving lights, that, apart from there motion, look like stars. What these are, are earth orbiting satellites. They shine with a white glow from sunlight reflecting off their metallic bodies and solar panels. 

The best time to look for satellites is during the first hour of darkness on spring and summer evenings. Try setting up a reclining lawn chair and watch the overhead region. Within a few minutes you should see several star like dots moving through the constellations. A satellite easily visible to the naked eye is typically the size of a delivery van, traveling at 17500 miles per hour and crosses the sky in two or three minutes at an altitude of 200 to over 300 miles.  Once you've had a little experience, telling the difference between a satellite and an airplane is easy. Most aircraft have either flashing lights or red or green wing lights, although a few have a steady white light like a satellite. Binoculars reveal engine exhaust or other lights on planes that appear to the naked eye as single white lights, satellites always appear white, starlike and untwinkling. 

If a satellite disappears as it crosses the sky, it has entered the earth's shadow. The shadow climbs higher as the sun sinks lower, which is why the best time to scan for satellites is the hour after darkness falls. Sometimes a satellite appears to pulsate in a regular rhythm, which means the entire device is tumbling. Active working satellites are always stabilized, so if the pulsing is obvious, you can be sure you're seeing something inactive or space junk.  

On Friday the 24th Jupiter and Venus will be about 10 degrees apart and closing. There are now only three planets in the west out of the five we started with at the beginning of the month, these are Jupiter Venus and Mars. On Sunday the moon will be full.  

Monday, May 27th. Written by Joseph Slomka.

Home  • About Us  • Collections  • Education  • Events  • Grants  • History  • Skywatch  • Site Map & Index

Dudley Observatory
107 Nott Terrace, Suite 201
Schenectady, NY 12308
(518) 382-7583
info@dudleyobservatory.org