The Dudley Observatory

Skywatch Line for Friday, June 30, through Sunday, July 2, 2006
by Alan French

The International Space Station will pass over the capital district this
weekend, and you'll have two chances to see it. The ISS appears as a moving
star, and it is brightest and easiest to spot when it is highest in the sky.
We see the ISS because it is still up in sunlight while we are down in the
Earth's shadow. These passes will be interesting because the ISS will move
into the Earth's shadow and fade from view before it moves below the
horizon.

The times given here are for Schenectady, but they should be close enough
for anyone living in the capital district.

On Saturday night, the ISS will appear above the northwestern horizon at
10:04. I often find I do not spot it until it has risen a bit higher in the
sky, so you might not see it until a little after the appearance time. The
ISS will be highest at 10:06:44 when it will be 52 degrees above the
north-northeastern horizon. If you didn't spot it coming up from the
horizon, look very high in the north-northeast at 10:06 and watch for a
bright star moving toward the east.

The ISS will begin moving into the Earth's shadow and fading from view at
10:08:21 when it is still 22 degrees above the eastern horizon. How long
can you see the ISS before it vanishes from sight?

On Sunday night, the ISS will appear above the west-northwestern horizon at
10:26:44. It will be highest at 10:29:28 when it will be 50 degrees above
the southwestern horizon. If you missed it coming up from the horizon, look
high in the southwest at 10:29 for a bright star moving toward the south.

The space station will begin moving into the Earth's shadow at 10:30 when it
is still 44 degrees above the southern horizon. Watch as it slowly fades
from view as it moves deeper into the Earth's shadow.

Flight Engineer Jeff Williams and Commander Pavel Vinogradov currently man
the ISS. The shuttle Discovery is scheduled for launch at 3:49 PM EDT on
July 1, and it will dock with the space station. According to the NASA
timeline, Discovery will dock with the ISS on day 3 of the mission.
Discovery is delivering European Space Agency astronaut Thomas Reiter to the
ISS. He will return the station to three crewmembers.

This is the Dudley Observatory Skywatch Line for Tuesday, July 4th, Independence Day, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 5:24 AM, and it set tonight at 8:42 PM. Sunrise tomorrow will be at 5:24 AM and Sunset will be at 8:41 PM.

The First Quarter Moon was yesterday, so starting today the Moon is in a waxing Gibbous phase. It rose this afternoon at 2:19, and will set a little after midnight. Tomorrow it will rise at 3:22 PM, and will set at 1:00 tomorrow morning. Tonight and tomorrow night, the Moon will be near the planet Jupiter.

Mars and Saturn are very low in the west about an hour after Sunset a few degrees from each other and the Planet Jupiter is high up in the south west in the constellation of Libra. Look for Leo the Lion in the south west, and the Big Dipper just west of directly overhead.

The bright stars of the Summer triangle, Vega, Deneb, and Altair are in the east after 10 PM, getting higher each night.

Venus, the brightest object in the Solar System after the Sun and the Moon, is in the east about an hour before Sunrise. By that time, the Summer Triangle and the Milky Way are west of overhead.

Yesterday, July 3^rd, the Earth was at Aphelion, farthest from the Sun. However, the Northern hemisphere is tilted towards the Sun, so we get more direct rays of Sunlight, and warmer weather.

Public Programs at the Suits-Bueche Planetarium at the Schenectady Museum, are on Saturdays and Sundays at 1, 2, and 3 P. M. The 1:00 program is “The Sky Above Mister Rogers Neighborhood”, a program for young people. At 2 P. M. is “Hubble Vision”, and at 3 P. M. is a live narration of the Summer Sky. “Hubble Vision” also plays Tuesday through Fridays at 2 PM.

The Sun sets tonight at 8:36 PM. The waxing gibbous moon rises today at 3:21 PM and sets tomorrow morning at 1:20 AM.

Of the naked eye planets, only Jupiter is easily visible in the evening sky as Mercury, Saturn and Mars are very low in the west at sunset. Jupiter, at brighter than minus two magnitude, will be unmistakable, but, if you need a little help, this evening it will be less than six degrees above the Moon. Venus, on the other hand, is a morning star rising at 3:24 AM Thursday morning, or two hours before the Sun, in the constellation Taurus, the Bull. Look low in the east northeast before sunrise. At almost minus four magnitude, Venus should be readily visible if you have a good view of the horizon.

Summer is, for many sky watchers, a particularly special time of year. It is during summer that the constellations Scorpius and Sagittarius, never very high in the sky from our part of the world, are at their highest. Try spending a few hours outside some clear, dark summer evening. First Scorpius, then Sagittarius, passes the meridian and reaches their highest point in the sky. When an object passes the meridian, we say that it transits or culminates. Circumpolar objects actually culminate twice, once when they reach their highest point in the sky as they pass from east to west, and once when then pass the meridian between the pole and the horizon. The former is referred to as upper culmination and the latter as lower culmination. But back to Scorpius and Sagittarius.

Looking in the direction of Scorpius and Sagittarius, we are peering toward the center of our own galaxy. And what a beautiful sight it is. First, we see the Milky Way rising like steam from the spout of the teapot asterism in Sagittarius. Second, a simple pair of binoculars will reveal numerous treasures simply by scanning the area.

When out observing on a recent night, I let my telescope sit idle while using a simple pair of 10 X 50 binoculars. Turning toward the area in question, I could easily spot, from Messier’s catalog, M 6 and M 7, two beautiful open clusters in Scorpius, M 4 in Scorpius and M 22 and M 28 in Sagittarius, three globular clusters, and M 8 and M 20, two diffuse nebulae in Sagittarius. In a telescope, a more magnified view reveals why M 8 and M 20 are referred to as the Lagoon and Triffid nebula, respectively. And there’s more. In particular, the area is a treasure trove of globular clusters great and small, as well as open clusters and diffuse nebulae, many visible in binoculars or a small telescope.

Skywatch line for Thursday, July 6, 2006
by Ray Bogucki

The planet Mercury is now very difficult to find very low in the West at sunset. Mercury sets just 40 minutes after the Sun while the sky is still bright with twilight glow. It will pass between Earth and the Sun in mid-July and then reappear, rising before the Sun as a morning star in the last few days of July. Saturn, a little above and to the left of Mercury, is still visible low in the West at sunset. The ringed planet sets about an hour and a half after the Sun while some fading twilight still remains on the western horizon. Although Saturn can still be spotted, observers with telescopes will find the image badly degraded as the light from the planet travels through a long path of the densest, dirtiest and most turbulent air just above the horizon. Mars, a little above and to the left, or east, of Saturn, sets about 2 hours after the sun and suffers from the same imaging problems as Saturn, but will still be detectable for a few more weeks.
The only good planetary viewing in the evening skies lies with Jupiter, which now shines about 30 degrees above the south-southwestern horizon at nightfall. This bright, minus 2.2 magnitude beacon dominates the evening sky. Tomorrow (Friday) night, Jupiter will put on a show for viewers with telescopes when the third Galilean moon, Ganymede, will cast its small, but easily visible shadow on Jupiter's surface. The little dark spot will enter Jupiter's disc just after 11 p.m. The shadow will transit across Jupiter's face for about two hours, exiting the disc shortly before the planet sets.
Two months ago, the Earth overtook and passed Jupiter, placing it at opposition. Earth's faster orbital speed made Jupiter appear to be moving backwards or westward among the stars in what is known as retrograde motion, but tonight the retrograde motion ends. Earth has reached a section of its orbit in which we are currently traveling directly away from Jupiter, so it will appear to remain stationary among the stars. By tomorrow night, it will begin slowly to return to its normal eastward motion among the stars until we approach the opposition of Jupiter again next year.
As a final note, observers who have noticed a faint haze in the air even on clear nights may be seeing a highly diffuse layer of smoke from forest fires burning in Saskatchewan Province in western Canada carried here by the prevailing westerly winds.

This is the Skywatch Line for Friday, July 7, through Sunday, July 9.
by Alan French

The Moon was at first quarter on Monday, July 3, and it will be Full this
coming Monday, July 10, so bright moonlight will dominate the weekend sky.

The Moon will be farthest south on Sunday night, July 9. If you look to the
southeast just before 10:00 PM, you will find the Moon only 12 degrees above
the horizon, and in the "Teapot" pattern of stars that makes up the
constellation Sagittarius. Objects in the sky are highest when they are due
south, yet Sunday night's Moon will be only 18 degrees above the horizon
when it is due south just after midnight.

The space shuttle Discovery is now docked to the International Space
Station. Unfortunately, we have only one chance to see the ISS pass over
our area, and that occurs on Friday night. The ISS will not be very high in
our skies, but it will be fun to see the ISS and know that the Discovery and
her crew are also up there.

To see the ISS you will need a good view to the southwest, and it would be
an added bonus if the view was also good to the west and south. The ISS
does not appear as bright when it is low in the sky, so you'll also want
clear, haze free skies.

Watch for the ISS coming up from the western horizon, traveling fairly low
on the horizon, at 9:10:37 PM. The ISS will pass below the bright star
Regulus, about half way down to the horizon. The ISS will be highest at
21:12:38 when it will be 18 degrees above the southwestern horizon.
(Remember that a fist held at arm's length spans 10 degrees across the
knuckles.) When highest the space station will be passing through the top
of the constellation Corvus, the Crow.

After passing through Corvus, the ISS will pass below Spica, about half way
down to the horizon, and then below Jupiter, the brightest star toward the
south. The ISS will vanish from view toward the south just before 9:15 PM.
We will not see the ISS again until the end of the month, when it will be in
the morning sky.

Skywatch Line for Monday, July 10.
by Joe Slomka

The Sun sets tonight at 8:35 PM and ends with nightfall at 10:46. Dawn breaks at 3:16 and ends with sunrise at 5:27 AM.

The Moon turns Full at 10 PM tonight. This means that it rises at sunset and sets at sunrise. It also means that the Moon's glare hinders observation of all but the brightest objects.

Three of those are planets. Saturn and Mars lie low in the southwest. At sunset they are moderately low, but can be hidden by trees or hills. Saturn is brighter and slightly higher; its creamy white color identifies it. Mars is smaller, dimmer and to Saturn's lower right. It will be more difficult to pick out of the twilight, but the distinct red color should give it away.

Jupiter is higher and almost due South. Its brilliance easily overcomes the Moon's glare. Even its four satellites are easily seen tonight in binoculars.

On moonless nights, amateur and professional astronomers may observe a satellite racing through the field of view or through a photograph. It is a common occurrence, and most people do not give it another thought. This date in 1962 marks a milestone. Telstar, the first commercial satellite, was launched.

The first artificial satellite, Sputnik, was launched in 1957. A series of military and scientific satellites followed. However, long before Sputnik, Arthur C. Clarke, a novelist, had a different dream. In 1947, he wrote a paper predicting that a satellite placed in a special orbit could act as a relay for radio signals. Clarke said that, if you launched a satellite into orbit high above the Earth at the same speed as the Earth's rotation, the satellite would appear to be stationary in the heavens. AT&T first launched Echo, a silvered plastic balloon, which literally bounced signals across the Atlantic. On July 10, 1962, AT&T launched Telstar, a true relay station. Telstar received and retransmitted signals between the US and Europe. Today, many such satellites crowd our skies and make worldwide television, telephone and Internet service routine. Telstar also paved the way for commercial services like dish TV and radio services.

This is the Dudley Observatory Skywatch Line for Tuesday, July 11th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

The Moon is in a waning gibbous phase today, rising at 9:37 PM, and setting at 6:56 tomorrow morning.

The bright stars of the Summer triangle, Vega, Deneb, and Altair are in the east after 10 PM, getting higher each night.

Venus, the brightest object in the Solar System after the Sun and the Moon, is in the east about an hour before Sunrise.

High overhead during July, you can find a small horse-shoe shaped group of stars known as Corona Borealis, which means "Northern Crown". To the east of the crown lies the constellation of Hercules, which contains the famous star cluster known as the Hercules Cluster. It was discovered by Edmund Halley (of comet fame) in 1714, and was the 13th object catalogued by Charles Messier in 1764, hence the astronomical name; M13.

The Hercules Cluster contains about 100,000 stars, and is around 14 billion years old. In 1974, a radio message was sent out to this cluster from the Arecibo Radio Telescope, in hopes that any intelligent life may get the message and respond. The Cluster is so far away, that the message will not reach there until roughly the year 25,000, YES, twenty five thousand!
It is visible in a good pair of binoculars or a small telescope.

The Sun sets tonight at 8:33 PM. The waning gibbous moon, in Capricornus, rises at 10:09 PM and doesn’t set until 8:13 AM tomorrow morning. With the full moon having occurred late last Monday, and being in the sky virtually all night, its light will seriously interfere with any astronomical observing, except for Jupiter during the evening and brilliant Venus before sunrise.

Perhaps one of the most difficult aspects of the universe to comprehend is that of scale. Imagine going to a star party some summer evening when the moon is a waxing crescent. Before the moon sets, many telescopes are pointed at the moon, whose mean distance from earth is about three hundred eighty-four thousand kilometers. At that distance, even binoculars will show several craters in addition to the maria, which the ancients mistook for seas, and small telescopes will show a wealth of detail.

Next, our attention is turned to Jupiter, whose distance from the Sun is more than five time’s that of Earth’s. When talking about objects in our solar system, except for the moon, the basic unit of distance employed is the astronomical unit, which is, approximately, the average distance of the Earth from the Sun, somewhat less than one hundred fifty million kilometers. When talking about the distance to the stars and beyond, we use the term light year, or the distance light travels in one year at the speed of just under three hundred thousand kilometers per second. In those terms, an astronomical unit is just over eight light minutes.

The nearest star to the Sun, actually a system of stars, is alpha Centauri, which is approximately 4.3 light years away. Regular listeners know that some stars are bright because they are close, such as Vega, at twenty-six light years distant, or because, though distant, they are intrinsically bright. A prime example is Deneb which, though not quite as bright as Vega, is seventeen hundred light years away.

Most of the objects you are likely to observe within our own Milky Way galaxy have distances measured in hundreds or, even, thousands of light years. The famous Ring Nebula in Lyra, lies some two thousand light years away. The brighter Dumbbell Nebula, in Vulpecula, lies a thousand light years distant. Other nebulae and open clusters may be somewhat closer, maybe a few hundred light years away, or further, up to several thousand light years distant.

Next Wednesday, we’ll venture out to the globular clusters surrounding our galaxy and to galaxies beyond our own Milky Way.

Skywatch line for Thursday, July 13, 2006
by Ray Bogucki

The constellation, Scorpius the Scorpion, is one of the brightest and most spectacular of the zodiac constellations. It lies low in the south at nightfall, and, at our midnorthern latitudes, puts in only a short appearance during the summer months. Scorpius is one of the few constellations whose star pattern actually suggests the shape of the object it represents. To see the whole pattern from this area, your best bet is to find a hilltop with an unobstructed view of the southern horizon. You will immediately recognize the two stars marking the scorpion's claws leading back to the three stars in a line forming the head, then passing though the bright reddish star, Antares, the heart of the scorpion, and continuing on until the segmented tail turns sharply upwards, ending in the bright star Shaula, which marks the sting hanging over the scorpion's back.

In mythology, the gods had become alarmed by the threat of the great warrior Orion to slay all of the animals on Earth. To prevent this disaster, they sent Scorpius to sting Orion. In the venomous battle that ensued, Orion was poisoned by the sting and died. To reward Orion for his unquestioned prowess as a hunter, they placed him among the stars of the winter, and to reward Scorpius for his compliance, they placed him among the stars far from Orion in the summer skies so there could be no further confrontation between the two enemies.

In ancient Rome, when Julius Caesar established the new Julian calendar, the Roman astrologers decided that they needed to add another zodiac sign, but all of the sites along the ecliptic, the path of the zodiac, were already assigned. They finally decided to insert a new sign which they called Libra, the Balance, between Scorpius and Virgo. They made the new space by cutting off the two bright stars marking the scorpion's claws and assigning them as a few surrounding fainter stars to the new constellation, Libra. This astronomical surgery is memorialized by the delightful ancient Arabic names of the two stars; Zuben el Genubi (zoo-BEN-el-jeh-NOO-bee) and Zuben Eschamali (zoo-BEN-ess-ska-MA-lee), which translate as "Southern Claw" and "Northern Claw" respectively. Next Thursday's Skywatch line will discuss some of the celestial treasures to be found in Scorpius.

This is the Skywatch Line for Friday, July 14, through Sunday, July 16.
by Alan French

Mars is still visible in the western sky just after sunset. During the
coming week the eastward motion of Mars will move it closer and closer to
the bright star Regulus. On Friday night, they will be five degrees apart.
A week later, they will be less than a degree apart.

On Friday night, look for the pair around 9:30 PM. They will be just a
little north of due west, and less than 10 degrees above the horizon. Mars
will be 7 degrees above the horizon, and Regulus will be two degrees higher
and a little less than five degrees from the red planet. If you have
trouble spotting them with your eyes alone, try looking with binoculars.

By Saturday night, the pair will be just over four degrees apart, and the
distance will have shrunk to less than four degrees by Sunday night. By
next weekend, they will be even lower in the sky at 9:30 PM, and separated
by less than one degree.

Weather permitting the Albany Area Amateur Astronomers will host a public
Star Party this weekend. At a Star Party a variety of telescopes are set up
for your viewing pleasure, providing views of galaxies, star clusters,
nebulae, and pretty double stars. During the early part of the Star Party,
club members will have their telescopes pointed at some of the celestial
showpieces. Later on, we take requests, as long as the object is above the
horizon.

The Star Party will be held Saturday night in Indian Meadows Park in
Glenville, beginning at 10:00 PM. Indian Meadows Park is off of Droms Road
in East Glenville, and is marked by a large sign on the eastern side of the
road. After passing the park buildings, bear left at the fork in the road,
and continue to a gravel parking lot on your left. The telescopes are set
up beyond the gravel parking lot. Please park in the gravel lot and walk to
the telescope area. If you are bringing a telescope, you may drive to the
observing area, but try to arrive early.

There is no admission charge and all ages are welcome. You are welcome to
stay as long or as briefly as you wish. Star Parties are canceled if the
skies are mostly cloudy. Call Jim or Marion Shearer at 399-6603 to verify
a cancellation due to cloudy skies.

The Albany Area Amateur Astronomers will meet at 7:30 PM this coming Tuesday
at the Schenectady Museum. Club member and Rising Star Intern Josh
Marsfelder will talk about how amateurs can contribute to our knowledge of
the universe. Club meetings are free and guests are always welcome.

The Sun sets tonight at 8:30 with night falling at 10:37 PM. Dawn breaks at 3:27 tomorrow morning and ends with sunrise at 5:33.

As the sky darkens, Jupiter attracts our attention as the brightest object in the sky; however, Mars can still be glimpsed low in the southwest. If trees or hills fail to hide Mars, see if you can track it this week. It slowly approaches Regulus, the brightest star in the constellation Leo. Saturday night finds them the closest; after which Mars passes Regulus.

Jupiter itself chases another star, Zuben-el-genubi, also known as Alpha Librae. Libra is diamond-shaped. Alpha is the brightest star and on the side nearest Jupiter. They approach each other throughout the month. Jupiter sets around midnight.

In the brief interval between Jupiter-set and Moonrise, the vast Milky Way spreads from North to overhead to South. Now is the ideal time to scan the area with binoculars. There are many star clusters and gas clouds. The region surrounding Sagittarius is especially rich.

The Last Quarter Moon rises after midnight and illuminates the pre-dawn sky. Shortly before sunrise, Venus joins the Moon. Venus lies low in the East. It holds its position now, but will soon begin to dip into the Sun's glare.

As appropriate for the upcoming racing season, two horses appear by midnight. The largest horse is, of course, Pegasus. The smallest is Equuleus. This dim constellation is easy to find. Pegasus flies upside down and is easily identified as a Great Square. Two thin chains sweep northward from the upper left. If one sweeps across the chain, binoculars reveal a large hazy oval; this is revealed, in telescopes, to be the Andromeda Galaxy at about two and a half million light years distant. You can see it with the naked eye under rural skies. Pegasus' neck flows from the lower right corner and angles up. Equuleus is the small angular line of stars West of the Pegasus' nose. A globular star cluster, M 15, lies exactly halfway between Pegasus' nose and Equuleus. This too is easily seen in binoculars.

This is the Dudley Observatory Skywatch Line for Tuesday, July 18th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 5:32 AM, and it set tonight at 8:30 PM. Sunrise tomorrow will be at 5:33 AM, and it will set tomorrow at 8:29 PM.

The Moon was at Last Quarter yesterday, so today it is a waning crescent. It will rise just after midnight tonight, and will set at 3:50 tomorrow afternoon.

Mars and Saturn are so low in the west that you have to catch them before it gets totally dark out. The Planet Jupiter is getting lower and lower each week, but can still be seen as a bright starlike object in the south west after darkness.

The bright stars of the Summer triangle, Vega, Deneb, and Altair are in the east after 10 PM, getting higher each night.

Venus, the brightest object in the Solar System after the Sun and the Moon, is in the east about an hour before Sunrise. The Moon will be near Venus on Saturday morning.

The Sun sets tonight at 8:28 PM. The waning crescent moon has, by then, already set, at 3:51 PM, and rises Thursday morning at 1:06 AM in the constellation Taurus, the Bull. Look for the moon less than a degree north of the Pleiades star cluster.

Last Wednesday I wrote of the concept of scale and distance in the universe. Starting with Earth’s moon we then moved on to the giant planet Jupiter where it became necessary to change the unit of distance from the kilometer to the astronomical unit. Moving on to the stars, nebulae and open clusters, we employ the light year, the distance light travels in one year. For those objecting to last Wednesday’s use of metric units, the moon’s mean distance from the Earth is approximately 239,000 miles, the astronomical unit is approximately 93 million miles, and the speed of light is slightly faster than 186,000 miles per second.

All the stars visible in the night sky belong to our own Milky Way, a spiral galaxy with a central bulge approximately 100,000 light years in diameter and 2,000 light years thick. We lie in a spiral arm approximately 30,000 light years from the center. The nebulae and open clusters we see at night lie near or near one of the spiral arms.

And inhabiting a halo surrounding our galaxy, we come to the globular clusters. One of the closest visible in our skies, is M 22 in Sagittarius at ten thousand light years away. The famous Hercules Globular Cluster, M 13 is a whopping 23,500 light years away.

The closest galaxies are the Large and Small Magellanic Clouds, companion galaxies to our own, which lie some 169,000 and 190,000 light years away, respectively. They are in the southern sky, not visible from our latitude.

If you stay out late enough, you will probably get to see the Great Andromeda Galaxy, visible without optical aid under clear, dark skies. The furthest object easily visible to the naked eye, its lies 2.4 million light years away. Like the Milky Way, it is part of the Local Group, as is M 33 in Triangulum, which is approximately 2.7 million light years away. Both objects are readily seen in binoculars. Most galaxies, in fact, are found in groups, many visible in amateur telescopes.

On a grander scale are galaxy clusters, such as the famous Virgo galaxy cluster, whose center lies some 70 million light years away. On a cosmic scale, the Virgo cluster is relatively close, with our Local Group on its fringe. Its members are prime targets for amateur astronomers in the Spring. And amateurs with large telescopes may even hunt down galaxies in cluster as far away as a billion light years.

Skywatch line for Thursday, July 20, 2006
by Ray Bogucki

At nightfall the bright constellation Scorpius crawls along the southern horizon. Last week we discussed the mythology and celestial surgery of the Scorpion. This week we examine a few of the fascinating sights in Scorpius.
The first point of interest is the alpha star, Antares, the brightest star in the constellation with its distinctly orange hue. The ancient name Antares means "Rival of Mars" and they are rivals in a couple of somewhat superficial ways. Antares is a bloated red supergiant with a staggering diameter that would encompass the entire orbit of Mars. Its orange color arises from its relatively cool surface temperature, about 3,000K. Mars, also orange colored, gives off no light of its own but only reflects sunlight from its rocky and dusty surface. The surface minerals contain much iron oxide, or rust, which reflect the reddish part of sunlight very well.
Both of these rivals also vary in brightness. Antares seems to undergo a long term pulsation of expansion and contraction in size leading to variation of about 40% in brightness. The change in the brightness of Mars is much more dramatic and exists for a different reason. When Earth and Mars are on opposite sides of the Sun in their respective orbits, they are about 250 million miles apart and Mars shows a tiny disk, less than 4 arc-seconds, in a telescope. When Earth overtakes Mars on the same side of the Sun, we approach to within about 35 million miles and Mars' disk swells to 24 arc-seconds and it appears 75 times brighter, second only to Venus among the planets.
About three Moon-widths to the right, or west, of Antares, binoculars or a small telescope will show a large cluster of stars known as M4, a globular cluster which, at 7,000 light-years, is perhaps the closest one to our Solar System. Globular clusters are spherically arranged groupings of hundreds of thousands or even millions of stars which may be 10 billion years old, some of the ancient remnants of the formation of our galaxy.
If we follow the line of stars outlining the back of the Scorpion to its very end, we come to Shaula, "The Sting", hanging over the Scorpion's back. A few degrees east of Shaula, in a dark sky, the naked eye can detect M7, a fuzzy patch of light, which shows up in binoculars or telescope as another type of star cluster, known as an open cluster, with tens or hundreds of very young stars born at the same time from the same gas or dust cloud. The Pleiades in Taurus are a well-known, and easily found cluster of this type. A slow seep of Scorpius with binoculars will reveal other star clouds, multiple stars and other wondrous sights in this very rich region of the Milky Way, close to the central bulge of our galaxy.

This is the Skywatch Line for Friday, July 21, through Sunday, July 23.
by Alan French

Last weekend we talked about the eastward motion of Mars among the stars and
how Mars was moving closer to Regulus, the brightest star in Leo, the Lion.
This weekend the pair is even closer together, and they will be closest on
Saturday night.

To catch them you will need a good, clear view of the western horizon and
you'll need to look for the pair at 9:25 PM. They will be a little over
five degrees above the horizon then, and the sky should be dark enough to
spot them. (Remember that your first three fingers, held at arm's length,
span five degrees.) If you wait until later, the skies will be darker, but
they will be even closer to the horizon, and probably much harder to spot.
They set just before 10:00 PM. If the horizon is clear and you have trouble
spotting the duo, try looking for them with binoculars.

On Friday night, Regulus will be just three quarters of a degree apart and
Mars will be to the upper right of Regulus. On Saturday night, they will be
just a little closer together, and Mars will be just above Regulus. By
Sunday night, the distance will have increased slightly and Mars will be
just to the upper left of Regulus.

Weather permitting the Albany Area Amateur Astronomers will host two public
Star Parties this coming weekend. At Star Parties a variety of telescopes
are set up for your viewing pleasure. During the early part of the Star
Party, club members will have their telescopes pointed at some of the
celestial showpieces. Later on, we take requests, as long as the object is
above the horizon.

Star Parties will be held on Friday, July 21, and Saturday, July 22. Both
Star Parties are at George Landis Arboretum in Esperance, and begin at 10:00
PM. If you enter Esperance traveling west on Route 20, watch for the
arboretum sign on your right, immediately after crossing the bridge over the
Schoharie River. After taking the right, follow the signs to the arboretum.
Continue up the hill past the main parking area and farmhouse, and turn
right into the Meeting House drive as you reach the top of the hill. A
reflective "Star Party" sign will mark the driveway.

The Star Parties will be canceled if the skies are mostly cloudy. If in
doubt, call 374-8460 after 6:00 PM.

The Sun sets tonight at 8:25 PM, with night falling at 10:27. Dawn breaks at 3:38 AM and ends with sunrise at 5:40.

The prominent feature of tonightâ€™s sky is the absence of the Moon. The Moon turns new at 12:31 AM. This means that the Moon is so close to the Sun that it will not be seen tonight.

There are two relatively bright planets to see. Mars is low in the West at sunset. It is so low that trees or hills could hide it. Mars is very close to Regulus, the brightest star in Leo. If you have trouble finding Mars, Regulus, the base of a backwards question mark, can help. The two are separated by a degree and a half. Both should fit in a single binocular view.

The other bright planet is Jupiter, the King of the Planets. Shortly after sunset, Jupiter blazes in the southern sky. Ordinary binoculars should show three moons surrounding Jupiter. Nightfall finds Jupiter low in the West, preparing to set shortly after Midnight.

Dawn finds only Venus, low in the East. Venus blazes brightly about twenty degrees above the horizon. Binoculars show it nearly in full phase.

With the Moon out of the way, observers are able to study dim or obscure objects. Several dim but lovely constellations are sandwiched between brighter Pegasus, Aquarius and Cygnus. One of these is Delphinus, the Dolphin. It looks like a diamond with a tail and replicates a dolphin leaping out of the water. It is found midway between Pegasus' and Cygnus' noses.

Most star names are derived from legends or description. Delphinus is an exception. Its two brightest stars, Alpha and Beta, were the subjects of a practical joke. An Italian astronomer, Niccolo Cacciatore, decided to give them proper names. In Latin, his name was "Nicolaus Venator". He assigned the name "Sualocin" to Alpha, and "Rotanev" to Beta. These names are "Nicolaus Venator" spelled backwards. The practical joke stuck! Today, these are accepted proper names for Alpha and Beta Delphini.

This is the Dudley Observatory Skywatch Line for Tuesday, July 25th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 5:39 AM, and it set tonight at 8:24 PM. Sunrise tomorrow will be at 5:40 AM, and it will set tomorrow at 8:23 PM.

The Moon is at New Moon phase today, the phase that cannot be seen from the Earth, as the Moons lit up side is facing away from us. Look for the very thin crescent, low in the west on Thursday evening. It will be near the planet Mars around 45 minutes after Sunset.

The Planet Jupiter is the only planet in the evening that is in good view. Look for it in the south west after darkness. It will appear as the brightest starlike object in the sky.

The bright stars of the Summer triangle, Vega, Deneb, and Altair are in the east after 10 PM, getting higher each night. Vega, is almost overhead at around 10 PM.

By 11:00 PM, you can find the Andromeda Galaxy low in the north east sky. It is our closest neighbor galaxy in space, and lies at a distance of 2.5 million light years away. To the naked eye, it appears as a dim smudge.

Venus, the brightest object in the Solar System after the Sun and the Moon, is in the east about an hour before Sunrise.

The Sun sets tonight at 8:22 PM. The moon, in Leo, was new yesterday afternoon and today will be low in the west at sunset. It sets at 9:29 PM .

Of the naked eye planets, Saturn and Mars are low in the west at sunset and will be extremely difficult to spot. Jupiter is still prominent at brighter than minus two magnitude in Libra, in the west southwest, but it sets shortly after midnight. Venus is prominent at almost minus four magnitude, rising at 3:44 AM Thursday morning in the constellation Gemini. Mercury rises less than an hour before the Sun and so will be extremely difficult, if not impossible, to spot.

At 10:00 PM tonight, the constellation Scorpius is due south, with Ophiuchus above and Sagittarius to its east. Peering toward where the three constellations meet we are looking toward the center of our galaxy. Much of Scorpius and Sagittarius are enmeshed in the Milky Way, which is particularly rich in this area. And, because of our vantage point well away from our galaxy’s center we can observe in that direction numerous globular clusters which inhabit a huge halo around the Milky Way.

Globular clusters are highly compact groups of old stars, from around a hundred thousand to perhaps a million or more. They are among the oldest objects in the universe. Located outside the plane of our galaxy, many are nevertheless found in the constellations of Sagittarius, Scorpius and Ophiuchus. In fact, the brightest globular cluster in the northern sky is M 22 in Sagittarius, near the top of the teapot asterism, although M 13 in Hercules is better known, possibly because, being viewed higher up, it is easier to spot.

Globular clusters vary in brightness, and our ability to resolve individual stars with amateur telescopes, in large part due to their distance, although some are intrinsically bright. M 13, for example, can be spotted without optical aid, even though it lies some 23,500 light years away. Containing around 300,000 stars it spans half the apparent width of the full moon. In contrast, M 4 in Scorpius is also around sixth magnitude but, as it is relatively close, less than 7000 light years away, it appears almost the size of the full moon, so its light is more spread out. Also, unlike M 13, M 4 never rises very far about the southern horizon, so we must look at it through a denser layer of Earth’s atmosphere.

Globular clusters each have their own “personality” and generally are best viewed in moderate to large size telescopes. If you go to a star party this summer, you are likely to see quite a few.

The Sun sets tonight at 8:17 PM with night falling at 10:15. Dawn breaks at 3:50 AM and ends with sunrise at 5:47.

As the sky darkens, Mars shines feebly in the West. It is quickly hidden by trees, buildings and, finally Earth itself. The six-day-old Moon glows low in the South. It is over one third illuminated and lies only one degree away from the bright star Spica in the constellation of Virgo. You many not spot Spica immediately, but it becomes obvious as the sky darkens. Jupiter shines East of the Moon and becomes more obvious by nightfall. Ordinary binoculars can see four of Jupiter's many moons by twilight's end: three are on one side, one on the other.

By midnight three dim and difficult planets are placed for persistent observers. Neptune inhabits Capricornus in the South, while Uranus lies in Virgo in the southeast. Uranus and Neptune can be seen through binoculars and small telescopes, but detailed star charts are necessary to find them. Pluto lies in a corner of Ophiuchus. This planet, which took years to discover, can be seen in large amateur instruments as a pinpoint among similar looking stars.

Tonight the Moon is quite visible in our sky. Earth has only one moon, while other planets have many; in fact, there are over 150 moons in our solar system. Only Mercury and Venus are without satellites. Most moons orbit their planets in the same direction as the planet's spin. This points to a common origin with the planet. Some moons are different. Our Moon is believed to be born of a catastrophic collision of Earth and another body. The Earth-Moon system can almost be called a double planet, since the Moon is so large. Most satellite systems are a fraction of their parent planets. The origin of Mars' two satellites, Phobos and Deimos, are also of questionable. Then there is Triton, one of Neptune's moons. It orbits in a direction opposite to Neptune's spin. Some researchers speculate that Triton was part of another system and was captured by Neptune, early in the Solar System's history.

Clear Skies