|
Dudley Observatory
Supporting research and education in astronomy, astrophysics, and the history of astronomy |
|
|
|
Skywatch September 2005 THURSDAY SEPTEMBER 1, 2005 by Barlow Bob Observe the dark night sky during the New Moon on September 3rd. The First Quarter Moon is on September 11th. The waning Moon is very thin when it rises just left of Mercury an hour before sunrise on September second. Bring binoculars to observe this event.
In twilight on September first, look low in the west - southwest for the astonishing sight of Venus, the brightest planet, very close to the second – brightest Jupiter. Hardly more than one degree separates them. This is less than the width of your little finger held at arm’s length. To their left is a dimmer star Spica.
Venus remains in good view for the rest of the month, but Jupiter sinks lower and deeper in the Sun’s afterglow each day, disappearing from view around the end of September.
Mars is getting very bright as it draws nearer Earth. It is rising earlier each night: Around 10:30 p.m. at the beginning of September. Stay up late enough for Mars to rise high and you will find that it’s displaying a globe large enough to offer a chance for very fine telescopic views. Mars will grow larger still during September.
Saturn rises several hours before dawn. All month it lingers near M44, The Beehive Cluster of stars. Binoculars or a low-power telescope provide fine views. A telescope at higher power also shows Saturn’s globe and its splendid rings.
Skywatch Line for Friday, September 2, through Sunday, September 4, 2005 This is the Dudley Observatory Skywatch Line for Tuesday, September 6th, Skywatch Line for Sept. 7, 2005 by Bernard Forman
Tonight the Sun sets at 7:18 PM followed by the waxing crescent Moon, which sets at 8:54 PM. New Moon occurred last Saturday and first quarter Moon occurs next Sunday. To the lower right of the Moon, also in the constellation Virgo, are Venus, at minus four magnitude, and Jupiter, to the lower right of Venus, at less than minus two magnitude. Jupiter sets at 8:39 PM, followed by Venus at 8:45 PM.
Of all the sights visible on a clear dark night, one of the most magnificent, and also easiest to see, is the Milky Way. Actually, the term refers both to our home galaxy and the misty band of light which seems to start in the constellation Sagittarius in the south, arches high overhead passing through Aquila and Cygnus, and through Cassiopeia and Perseus in the north. The Milky Way continues round the celestial sphere and is visible during winter nights, but is brightest in Cygnus, Aquila, Sagittarius and Scorpius.
Our Milky Way galaxy is an enormous spiral galaxy containing over a hundred thousand million stars. Primarily comprised of a central bulge, a disk and a halo, the Milky Way we view at night is the disk of our galaxy. While the central bulge and halo contain older stars and relatively little gas and dust, the disk is primarily populated with younger stars and considerable amounts of gas and dust. The disk is approximately one hundred thousand light years in diameter with our solar system being about two thirds of the way out from the center.
Find a dark location on a moonless summer night and wait until your eyes have become fully dark adapted. With nothing more than your eyes, scan the Milky Way from Sagittarius in the south to Cassiopeia in the north. Notice how its shape is not a smooth line, and how it splits in places, particularly obvious in Cygnus and Aquila. This is caused by the gas and dust blocking our view of the disk beyond.
With the naked eye, the Milky Way appears as an amorphous cloud. But a simple pair of binoculars reveals thousands upon thousands of stars. One of the great treats in amateur astronomy requires nothing more than sitting in a lawn chair or lying on a blanket, on a comfortable summer night and, binoculars in hand, scanning the Milky Way.
Skywatch Line for Friday, September 9, through Sunday, September 11, 2005
Skywatch Line for Monday, September 12 The Sun sets tonight a 7:10
with night falling at 8:47 PM. Dawn breaks at 4:56 AM and ends with sunrise at
6:33. Dudley Observatory Skywatch Line for Tuesday, September 13th, 2005
Skywatch Line for September 14 Tonight, the Sun sets at 7:06 PM. The waxing gibbous Moon, in the constellation Capricornus, rises at 5:38 PM and sets at 1:41 AM. First quarter Moon occurred last Sunday and the Moon will be full next Sunday.
At sunset tonight, Venus and Jupiter may still be seen low in the west southwest. Jupiter is dimmer and closer to the horizon than Venus, so Venus will be considerably easier to see. Mars, on the other hand, rises at 9:34 PM and is readily visible late tonight west of the Pleiades. Currently in the constellation Aries, the Ram, Mars rises high in the sky, and will be considerably higher at the next opposition in November than it was at its famously close opposition in 2003. Accordingly, though it will be slightly smaller than at last opposition, the views from our part of the world should be considerably better. Already, under steady skies, detail on the planet is readily visible in moderate size telescopes.
By sundown tonight, most of Scorpius has already set. Sagittarius is low in the southwest. The bright star low in the west is Arcturus. Once it is dark enough to see the Big Dipper, which is skimming the northern horizon, follow the arc of the Dipper’s handle to Arcturus.
Probably the first stars visible after the Sun has set are Vega and Deneb, high overhead, and Altair toward the south. These three stars make up the Summer Triangle, which is still prominent. To the west of the Summer Triangle is the constellation Hercules, roughly halfway between Arcturus and Altair. The most obvious part of Hercules is a group of four stars forming the “keystone”. A simple sky map or planisphere will make finding it easy.
Rising higher in the east is the Great Square of Pegasus, followed by the constellation Andromeda. One of the most famous deep sky objects in the entire sky is M 31, the Andromeda Galaxy. Halfway between third and fourth magnitude, the Andromeda Galaxy should be a naked eye object on a dark moonless night. However, the galaxy is large, over three degrees, or six times the Moon’s diameter, along is long axis, so its light is spread out. Any light pollution or haze will hide it. From a truly dark site, such as in the Adirondacks, the galaxy will appear as a faint, misty patch and is a glorious sight in binoculars. The Andromeda Galaxy is the largest galaxy in the Local Group, a small cluster of galaxies that includes our own Milky Way. At 2.2 million light years distant, it may be the furthest object visible without optical aid.
Skywatch Line for Friday, September 16, through
Sunday, September 18, 2005 The Sun now sets just after 7:00 PM, and rises around 6:39 AM. Every day it rises a bit later, and sets a little earlier as the Sun moves south and the days continue to shorten. Bright moonlight will dominate the weekend skies, and the Moon will be Full at 10:01 PM on Saturday night. The full Moon of September is called the Fruit Moon. This full Moon, being the full Moon closest to the Autumnal Equinox – the first day of Fall – is also the Harvest Moon. Around the autumnal equinox the Moon's path through the sky means it rises only about 30 minutes later each night, so there are several nights with bright moonlight illuminating the early evening sky - adding to the time early farmers could harvest their crops. The Moon will rise further north each night from now until September 24. Try to catch moonrise during the coming week and notice how much farther north it is by the end of the week. When it rises farther north it also travels higher in the sky, and on the 25th, around sunrise, the Moon will be quite high in the sky. The International Space Station will pass directly over the Capital District on Saturday night. We see satellites like the ISS because they are still up in the sunlight while we are down in the Earth's shadow. Satellites look like stars moving across the sky, and the ISS, because of its size, appears as bright as the brightest stars when it is high in the sky. The ISS will first be visible just before 7:43 PM Saturday coming up from the west-northwestern horizon. It will be highest and pass almost directly overhead just after 7:45, and will vanish into the Earth's shadow as it approaches the southeastern horizon at 7:48. On its journey across the sky it will pass very close to the star in the end of the Big Dipper's handle, and then extremely close to brilliant Vega. Vega is the brightest star in Lyra, the Lyre, and is almost directly overhead. After passing Vega, the ISS will pass by Albireo, the star that marks the head of Cygnus, the Swan, before vanishing from sight. The Albany Area Amateur Astronomers will meet at the Schenectady Museum at 7:30 PM this coming Tuesday night, September 20. This month's program is "Thirty Things You've Never Heard Of." On a nice clear night, you take your telescope out beneath the stars and wonder what to look at. You've gazed upon the Andromeda Galaxy, the Ring Nebula, the Great Cluster in Hercules, and the Pleiades a hundred times. What else can you see? Avid observer Sue French will introduce you to some of the lesser-known wonders of the deep sky, including treats to enjoy with any size scope. The meeting is free and open to all. This is the Skywatch Line
for Monday, September 19. Dudley Observatory Skywatch Line for Tuesday, September 20th,
2005, written by Steven Russo, Planetarium Manager of the Suits-Bueche
Planetarium at the Schenectady Museum.
Sunrise today was at 6:44 AM, and it will set tonight at 6:59 PM. It will
rise tomorrow at 6:45 AM, and will set tomorrow at 6:57 PM.
The Moon is currently in a waning gibbous phase, with the Last Quarter on
the 25th. It rose at 8:13 this evening, and will set at 11:10 tomorrow
morning.
On Thursday, at 6:23 PM, the season of Autumn will arrive in the
Northern hemisphere. Daylight and night will be about equal on that date.
Venus and Jupiter are low in the south west after Sunset. Venus is the
brighter of the two, and is farther to the east of Jupiter than it was last
week.
The Summer Triangle of Vega, Deneb, and Altair is getting higher up in
the sky each night in the north east, with bright blue Vega overhead by 8:00
PM. Running through the center of the triangle, is the Summer portion of
our Milky Way Galaxy. Appearing as a dim smudgy band of light under dark
skies, a pair of binoculars will reveal countless numbers of stars.
And don’t forget about the planet Mars, looking like an orange-reddish
star getting into good viewing position at around 11:00 PM in the east. The
Moon will be near Mars on the evening of the 22nd.
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 Friendly Stars”, a program for young people. At 2 P. M. is “Light
Years from Andromeda”, and at 3 P. M. is a live narration of the Summer Sky.
“Light Years From Andromeda” also plays Tuesday through Fridays at 2 PM.
Dudley Observatory Skywatch Line for September 21st Tomorrow is the first day of Autumn as the equinox occurs at 8:23 PM. The autumnal equinox is the point where the Sun crosses the celestial equator moving southwards. Currently that point is in the constellation Virgo. Interestingly, while the term equinox means equal night, day and night are not of equal length on the equinoxes. The equinox is calculated based upon the center of the Sun being on the ecliptic. However, at that time, the top of the Sun is still above the horizon. Also, refraction of the Sun’s image by the Earth’s atmosphere makes the Sun appear higher. Thus, on the equinoxes, day is somewhat longer than night. In addition to Mars, which rises at 9:09 PM and is prominent all night, Saturn rises after 2:00 AM and, at almost zero magnitude, is prominent in the east before dawn. At that time, Saturn is less than one and a half degrees from the Beehive Cluster in the constellation Cancer. The Beehive Cluster, also known as M 44 or the Praesepe, together with Saturn, will be a pretty sight in binoculars or a telescope capable of showing a wide field. By 11:00 PM tonight, the Summer Triangle is well to the west of the meridian and the Great Square of Pegasus is prominent in the south. The Milky Way crosses the sky overhead, going almost from due east to due west. With the Big Dipper skimming the northern horizon, Cassiopeia is prominent near the meridian, high up in the north. At about the same time, the Pleiades should become obvious in the east, followed by the red star Aldebaran and the Hyades open cluster, in Taurus. Of course, once we see these famous open clusters rising in the east, the winter constellation Orion can’t be far behind.
This is the Skywatch Line for Friday, September 23, through Sunday, This is the Skywatch Line for Monday, September 26 Dudley Observatory Skywatch Line for Tuesday, September 27th, 2005
Dudley Observatory Skywatch Line for Wednesday, September 28h,
2005 Tonight, the Sun sets at 6:41 PM, preceded by the waning crescent Moon at 5:01 PM. New Moon occurs on October 3rd. The Moon doesn’t rise until 2:46 AM tomorrow morning so, weather permitting, tonight should afford a good opportunity to observe the heavens. In fact, as the Moon approaches the New Moon phase, it rises later each morning, thus affording increasing time under dark skies for the next several days.
If you can possibly get to a star party this weekend, such as those held locally by the Albany Area Amateur Astronomers, by all means do so. Arrive early to watch people set up their equipment and dress warmly, as the nights are cooler now, and feel even colder because you don’t tend to move around much at star parties. Bring binoculars if you have a pair, and a red flashlight to help you see in the dark without ruining your night vision.
As late as 8:00 PM it still won’t be truly dark. Scorpius has already set and Sagittarius will be on the horizon in the southwest. But now may be one of your last chances until next summer to view some of the magnificent sights around the teapot asterism in Sagittarius. Scanning the sky above the teapot’s spout with binoculars, you can spot the Lagoon and Trifid nebulae. To the left of the star at the top of the teapot, you should be able to spot M 22, the largest globular cluster in the northern sky. Chances are likely that at least one of the amateur astronomers is thinking the same thing, and trying to get a last view of one or more of these objects through his telescope. Be sure to ask to have a look.
By 9:00 PM the sky should be relatively dark, and the Milky Way visible. One of the great pleasures in astronomy is scanning the Milky Way with binoculars so take some time to observe the Milky Way.
Once the sky gets dark, relatively bright objects, such as M13, the great globular cluster in Hercules, become spectacular sights. It’s a good idea to compare globular clusters, as they vary in brightness, size and the density of their stars. You may get to compare M 13 with M 92, also in Hercules, or M 56 in Lyra. Its also a good idea to compare how the same object appears in different telescopes, especially if you think you might want a telescope some day.
Other showpiece objects to look at in a telescope are the Ring Nebula, in Lyra and the Dumbbell Nebula in Vulpecula. Both are planetary nebulae, the outer shells of gas cast off from extremely hot stars late in their lifetimes.
There are galaxies on view, and your binoculars will show you the Great Andromeda Galaxy. In one of the telescopes, you should be able to also see two of its satellite galaxies.
Finally, Mars rises before 9:00 PM and will be a fascinating sight once it gets higher up later in the night. A view of Mars through a telescope will make your star party a memorable one.
Skywatch Line for Friday, September 30, through
Sunday, October 2, 2005 The skies are dark and moonless over the weekend, and current predictions are for clear skies, so it should be a fine weekend for stargazing. Mars now rises toward the east just after 8:30 PM, and the red planet continues to brighten as it moves toward its closest approach to Earth on October 30. It is large enough to show some detail through a telescope, especially if you look at Mars when it is high in the sky around 3:45 AM. A telescope magnifying just over 100 power will now make Mars appear as large as the Full Moon does to the unaided eye, and should reveal some dark markings on the planet. Weather permitting the Albany Area Amateur Astronomers will host public Star Parties this coming weekend. At Star Parties 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. Friday night's program is at the George Landis Arboretum in Esperance, and begins at 8:00 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. Saturday night's Star Party is in Indian Meadows Park in Glenville, also beginning at 8:00 PM. Indian Meadows Park is off of Droms Road in East Glenville, and is marked by a large sign. 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. Keep in mind that the temperature feels 20 to 30 degrees cooler when you are inactive under the night sky – so dress appropriately! Temperatures are predicted to drop into the lower 40s on Friday night, and to the upper 40s on Saturday. It never hurts to have some extra layers of clothing in the car – some guests leave early because they get chilled. Star Parties are canceled if the skies are mostly cloudy. Call Alan or Sue French at 374-8460 for more information or to verify a cancellation due to cloudy skies. |
|
|
|
|
Dudley Observatory |
|
|
Copyright © 2007 Dudley Observatory. All Rights Reserved. |
|