The Dudley Observatory

This is the Dudley Observatory Skywatch Line for Tuesday, September 5th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 6:23 AM, and it set tonight at 7:25 PM. Sunrise tomorrow will be at 6:25 AM, and it will set tomorrow at 7:23 PM.

The Moon is currently in a waxing gibbous phase today, with the Full Moon on Thursday. It rises at 6:34 PM today, and will set at 4:37 AM tomorrow morning.

Look southwest tonight about an hour after Sunset, and you will see what looks like a bright star. It is actually the planet Jupiter. The largest of the nine planets in our Solar System, it would take just about 12 Earths to form a line across its equator. A telescope of around 40 power will reveal the two main equatorial cloud bands, and as many as four moons orbiting the planet.

Look for the Summer Triangle of Vega, Deneb, and Altair after darkness. Vega will be the bright star overhead at around 9:00 PM.

Low in the Northeast at the same time, look for the Square of Pegasus, also known as the Fall Square. Nearby is the famous Andromeda Galaxy, our closest neighbor galaxy in space.

In the morning sky, just before Sunrise, look for Venus and Saturn. They are very low in the northeast. Venus is the brighter of the two, with Saturn just above it.

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.

Skywatch for September 6, 2006
by Bernard Forman

The Sun sets tonight at 7:21 PM. The waxing gibbous moon, in Aquarius, rises at 7:25 PM and sets tomorrow morning at 6:00 AM. Full moon occurs tomorrow.

Of the naked eye planets, only Jupiter is readily visible in the evening sky. Jupiter is in Libra, and sets before 10:00 PM. Look for Jupiter low in the west southwest after sunset.

Saturn, on the other hand, is a morning object. In the constellation Leo, the Lion, look for Saturn low in the east before dawn. Closer to the horizon is Venus, less than two degrees away from Regulus. Although much brighter than Saturn, Venus rises more than an hour later so dawn will definitely interfere.

With the moon almost full, and none of the naked eye planets well placed, tonight will not be particularly suitable for observing the sky, even if the sky is clear. Amateur astronomy can be a frustrating hobby. The planets can be studied even under light polluted skies or when the moon is up but only Mars, Jupiter and Saturn show much detail, and that’s not even true for Mars every year. And, like now, Jupiter and Saturn are not always well placed, high in the sky, where the atmosphere is steady. The moon is a glorious sight, but generally best observed at times other than full moon so that shadows show craters, mountains and other features in stark relief.

To observe deep sky objects we require dark, moonless nights away from artificial lights. Dry air affords transparent skies, highly desirable for observing dim, extended objects. Unfortunately, even when the sky is clear, a rare occurrence lately, moisture in the air often impedes our view. We feed the mosquitoes in the Spring and get chilled in the Winter. And, for most of us, it helps if all the right conditions occur on a Friday or Saturday night.

Although sometimes frustrated, amateur astronomers are, perhaps more than others, keenly aware of the changing seasons, and how the stellar patterns return to their place, at their time, year after year. An object missed due to a cloudy summer awaits the amateur astronomer a year hence. With each passing year, we visit old friends in the sky while we continue to hunt for dim objects never previously viewed. The sky is always there, but should be studied slowly and, perhaps, methodically. It reveals its beauty and mystery fully only to those willing to spend the time and effort necessary for something so vast.

Third, the plane of the Moon's monthly orbit around the Earth is tilted about 5 degrees to the plane of the ecliptic, the Sun's apparent path through the stars. The two planes intersect at two points opposite each other in the sky, known as nodes. The Moon passes through each node once in its monthly orbit, but the Earth's much longer orbital period places the Sun at each node only once each year. Only when the Sun is at or near a node can the Sun and Moon line up precisely enough to cause a solar or lunar eclipse. This year the Sun passes through the nodes to produce eclipse seasons in March and in September. True to form, there was one lunar and one total solar eclipse last March. Likewise, today's Full Moon will pass through the Earth's shadow to produce a partial lunar eclipse around 1 p.m., several hours before moonrise here, but observers on the other side of the Earth will enjoy the event. Two weeks from now, on Sept. 22, the New Moon will pass directly between the Earth and the Sun to produce a solar eclipse. But, remember that in two weeks the Moon will be at apogee and it will appear smaller than usual, not large enough, in fact, to completely cover the Sun. The result is known as an annular eclipse when even at maximum coverage the black, eclipsing Moon is surrounded by a fiery ring of Sun all around its circumference. This event will be witnessed, from land, only at the northern tip of South America.

Skywatch Line for Monday, September 11.
by Joe Slomka

The Sun sets tonight at 7:12, with night falling at 8:50. Dawn breaks at 4:55 AM, ending with sunrise at 6:32.

At sunset, Jupiter is the only planet visible. As the sky darkens, binoculars show Jupiter a half-degree above the Alpha Librae, the brightest star in the diamond-shaped constellation Libra. Alpha itself is a wide double star. All three can be seen within a single binocular field. By nightfall, Jupiter is very low in the West and too low for useful observation. Uranus and Neptune are the only visible planets, but detailed star charts and telescopes are necessary to find them.

Saturn is already up as the Sun rises. If Saturn looks a bit dimmer than usual, you are right. The highly reflective rings are closing their angle to Earth, reducing the planet's luminosity. Shortly before sunrise, Saturn is moderately high, with Venus hovering above the horizon. Even though Venus is much brighter, low clouds or trees may hide Venus. Within the week, Venus will be lost in the Sun's glare.

Listeners of the Skywatch Line know that the Milky Way, which tonight stretches from horizon to horizon, represents the rim of our galaxy. They also know that the faint glow in Andromeda is that of a giant galaxy, similar to ours. However, these "island universes" are not isolated from each other. Their gravitational fields clump galaxies into groups. The Local Group is made of our Milky Way, the Andromeda, M 33 in Triangulum, and about a dozen other galaxies. This group is traveling together through space. Some galaxies also interact with each other. A prime example is M 51, off the Big Dipper's Handle. A telescope shows one galaxy stealing material from another. Some astronomers think that giant galaxies like our own grow by absorbing smaller ones. Colliding galaxies are common telescope sights. It is thought that two spiral galaxies will merge to form an elliptical galaxy. In fact, in about three billion years, Andromeda and the Milky Way will probably collide and merge. The result will be a giant galaxy marked by very active star formation.

This is the Dudley Observatory Skywatch Line for Tuesday, September 12th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 6:31 AM, and it set tonight at 7:12 PM. Sunrise tomorrow will be at 6:32 AM, and it will set tomorrow at 7:10 PM.

The Moon is currently in a waning gibbous phase today, with the Last Quarter on Thursday. It rises at 9:43 PM today, and will set at 1:57 PM tomorrow. Look for the Moon, next to the star cluster known as the Pleiades or Seven Sisters, on the 13^th, about an hour and a half before Sunrise.

With darkness falling earlier each night, some of the brighter stars are visible by 8:00. At that time, the bright star Vega in the Constellation of Lyra the harp, is overhead. Vega is part of the famous Summer Triangle of Vega, Deneb, and Altair.

With this darkness at 8 PM, the Planet Jupiter is still visible as a bright star-like object, low in the south west. The largest of the nine planets in our Solar System, it would take just about 12 Earths to form a line across its equator. A telescope of around 40 power will reveal the two main equatorial cloud bands, and as many as four moons orbiting the planet.

As the skies darken by 9 PM, look in the north east for the square of Pegasus, also known as the Fall Square. Nearby is the famous Andromeda Galaxy, our closest neighbor galaxy in space.

In the morning sky, just before Sunrise, look for Venus and Saturn. They are very low in the northeast. Venus is the brighter of the two, with Saturn just above it.

Skywatch line for Thursday, September 14, 2006
by Ray Bogucki

A quick scan of the evening sky or a good sky chart reveals that, at this time, none of the bright planets are high in the sky for good observing. Jupiter still dominates the evening sky low in the southwest but it sets about 9:30 p.m. after less than an hour in a fully dark sky. The turbulent evening air near the horizon generally makes for very poor definition in a telescope. You may have noticed that Jupiter and the stars near it appear to be lingering in the west rather longer than usual. This impression arises because, while the stars and slow-moving Jupiter set about four minutes earlier each day because of Earth's daily advance in its orbit, the days are shortening so the Sun is also setting earlier by two minutes each day. Thus, Jupiter appears to be catching up with the Sun by only two minutes per day. This effect involves all the summer constellations which will linger in the west all through the autumn months, while the Sun sets earlier each day. The brilliant star Vega, which is nearly directly overhead at nightfall tonight will not be seen setting in the west at nightfall until Christmas time.

The two smallest planets, Mercury and Mars, are too close to the Sun to be seen at all this month. On the other side of the day, Venus can still be seen rising in the East, but it rises into a sky already bright with morning twilight, less than an hour before sunrise. it will continue to drop closer to the Sun until it finally passes, invisibly, behind the Sun in late October.

The one bright exception to all this planetary Sun-hugging is Saturn, the magnificent ringed planet, which rises into a dark sky about 4a.m., an hour before the onset of morning twilight. Like Jupiter and the stars, Saturn moves westward about four minutes each day, thus rising about four minutes earlier each morning. But, unlike the situation with Jupiter, the shortening days have the Sun rising a minute later each day so that Saturn is departing from the Sun by five minutes each day and seems to be vaulting into the early morning sky. The impression of Saturn's rapid daily ascent is reinforced by the observation that while Saturn rose this morning only an hour before morning twilight, by the end of this month it will be rising two and a half hours before twilight, providing excellent observing for those willing to get up at 4:30 a.m. when the atmosphere is usually more stable.

The Sun sets tonight at 7:00, with night falling at 8:36 PM. Dawn breaks at 5:03 AM and ends with sunrise at 6:39.

At sunset, Jupiter is the only easily seen planet. It is found low in the southwest and sets in two hours. As the sky darkens, binoculars help you pick out some of Jupiter's moons, but the rapidly sinking scene makes for shaky images.

By nightfall, Jupiter is very low. Uranus and Neptune, now the farthest planets, are visible low in southern skies. Telescopes and detailed star charts help in finding these distant worlds.

Early risers see a pretty scene about an hour before sunrise. Looking east, the observer spots Saturn moderately high. Saturn is the brightest object in that part of the sky, so identification is easy. Just below is a very thin crescent Moon. The next few nights find it rising later and lower. Below the crescent Moon is the bright star Regulus, the brightest star in the constellation Leo. If you get up early this week, note the changing positions of Saturn, Regulus and the Moon.

The general public thinks of astronomers as people who study the night sky. However, some astronomers study the nearest star of all - our Sun. Despite being so near, the Sun is not well understood. If you look at the Sun through a safe white-light filter, you see a white disk. Currently, only an occasional sunspot is seen. The Sun has an approximately 11 year sunspot cycle; we are now at the bottom of this cycle. Over the next five or six years the number of sunspots will increase. This increase has a direct effect on the Earth. When the Sun spits out a cloud of energetic particles, this cloud interacts with our atmosphere and causes the beautiful Northern Lights. More energetic events can also interfere with radio communications and damage satellites. One very violent flare shorted out the power grids in Quebec and Scandinavia. There is also evidence that lack of sunspots causes worldwide cooling. One such event in the Middle Ages caused a mini-ice age.

This is the Dudley Observatory Skywatch Line for Tuesday, September 19th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 6:39 AM, and it set tonight at 7:00 PM. Sunrise tomorrow will be at 6:40 AM, and it will set tomorrow at 6:58 PM.

The Moon is currently in a waning crescent phase today, with the New Moon on Thursday. It rose at 3:39 this morning, and set at 6:02 tonight. Look for the Moon, below the star Regulus and Saturn in the morning sky tomorrow. The Moon will be next to Venus on Thursday morning.

Darkness falls earlier each night, so some of the brighter stars are visible by 8:00. At that time, the bright star Vega in the Constellation of Lyra the harp, is overhead. Vega is part of the famous Summer Triangle of Vega, Deneb, and Altair.

The Planet Jupiter is still visible as a bright star-like object, low in the south west. The largest of the nine planets in our Solar System, it would take just about 12 Earths to form a line across its equator. A telescope of around 40 power will reveal the two main equatorial cloud bands, and as many as four moons orbiting the planet.

As the skies darken by 9 PM, look in the north east for the square of Pegasus, also known as the Fall Square. Nearby is the famous Andromeda Galaxy, our closest neighbor galaxy in space.

In the morning sky, just before Sunrise, look for Venus and Saturn. They are very low in the northeast. Venus is the brighter of the two, with Saturn just above it.

The Suits-Bueche Planetarium at the Schenectady Museum, will be closed starting on September 23^rd, and will re-open again on October 29^th. During that time, we will be installing the new GOTO Chronos Space Simulator Star Machine. Public programs this week will be at 2PM, Tuesday through Friday, at which time we will be presenting Hubble Vision

The Sun and Moon are major players in celestial events over the next two days. Tonight, just after midnight, the Moon will reach apogee and its farthest distance from the Earth for this year, at about 252,000 miles. A few hours later the Moon will enter its New phase, and because we are in an eclipse season, the New Moon will pass directly across the face of the Sun. Because the Moon is at apogee, its disk will appear smaller than usual and even at maximum eclipse, it will cover only about 93% of the Sun's disk, leaving a brilliant ring of sunlight around the Moon's black disk. This phenomenon is known as an annular eclipse. The Moon's antumbral shadow will touch down on the Earth's surface at sunrise at the northern tip of South America in Guyana, rushing eastward quickly through Surinam, French Guiana and the northern tip of Brazil before heading into the South Atlantic where it will remain until it disappears at sunset near Antarctica. A partial eclipse will be witnessed in South America and western Africa, but we are too far north to see any intrusion of the Moon's disk into the Sun.

Because the Moon is New, the next two weeks will be free of moonlight in the hours before sunrise. At this time of year, the plane of Earth's orbit around the Sun is tilted upward at a steep angle to the horizon in the eastern early morning sky. From a really dark sky location just before the beginning of morning twilight, about 4:30, look for the Zodiacal light, a large glowing pyramid of faint light rising at about 70 degrees to the horizon in the east along the ecliptic and encompassing the planet, Saturn. This is sunlight reflecting off the countless dust particles that are generated by asteroid collisions. They slowly spiral into the Sun, making the inner Solar System a rather dusty place.

This is the Skywatch Line for Monday, September 25.
by Joe Slomka

The Sun sets at 6:47 PM, with night falling at 8:22 PM. Dawn breaks at 5:12 AM and ends with sunrise at 6:47.

As the Sun sets look westward. The planet Jupiter appears quite low. Binoculars will confirm its identity as a planet, but observation of details will be difficult. The thin crescent Moon, only three days old, appears below and to Jupiter's right. It is so low that trees or buildings may hide it. It appears higher in succeeding nights.

Nightfall finds the sky in change. Many of the Summer Constellations are now setting and those associated with Fall and Winter are making their appearance. The first of these is Capricornus, east of teapot-shaped Sagittarius. Capricornus is a dim constellation, roughly triangular in shape. Capricornus is an ancient constellation, invented by the Babylonians. It leads the parade of water-based constellations: Aquarius, Pisces, Cetus, Cancer, Hydra and Eridanus.

The dim planet Neptune currently inhabits Capricornus.
Neptune can be seen in binoculars, but it takes a moderately large telescope and a detailed chart to identify it as a planet. Neptune is a gas giant planet. It is also a modern planet. The planet Uranus was discovered in 1781 (it is currently located in Aquarius). Irregularities in Uranus' orbit inspired a search for another planet. Newton's laws of planetary motion suggested a place to search. Johann Galle and Heinrich D'Arrest discovered Neptune in the place suggested, the constellation Aquarius, in 1846. The discovery of Neptune was a triumph of Newton's theory. Neptune takes over 163 years to orbit the Sun; it has yet to complete a loop since its discovery. Neptune is appropriately named. He is the Roman god of the Sea, and now reigns over the vest heavenly ocean.

Dawn finds Saturn low in the East. However, it is not the brightest object in the sky. The bright star Sirius blazes in the South. Saturn rises higher daily and will soon be prominent in our night skies. Venus is low in the East and preparing to pass behind the Sun and reappear in December's nights.

Clear Skies

Joe Slomka

This is the Dudley Observatory Skywatch Line for Tuesday, September 26th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

Sunrise today was at 6:46 AM, and it set tonight at 6:47 PM. Sunrise tomorrow will be at 6:47 AM, and it will set tomorrow at 6:45 PM. During this week, we have approximately 12 hours of day and 12 hours of night. Thus the name Equinox to describe the length of day during this time of the year.

The Moon is currently in a waxing crescent phase today, with the First Quarter on Saturday. It rose at 11:00 this morning, and set at 8:19 tonight. Look for the Moon, low in the southwest after Sunset. Tonight it will be near the Planet Jupiter. Watch its eastward motion against the background of stars during the next several nights.

Darkness falls earlier each night, so some of the brighter stars are visible by 7:30. At that time, the bright star Vega in the Constellation of Lyra the harp, is almost overhead. Vega is part of the famous Summer Triangle of Vega, Deneb, and Altair.

The Planet Jupiter is still visible as a bright star-like object, low in the south west.

As the skies darken by 8 PM, look in the north east for the square of Pegasus, also known as the Fall Square. Nearby is the famous Andromeda Galaxy, our closest neighbor galaxy in space.

In the morning sky, just before Sunrise, look for Venus and Saturn. They are very low in the northeast. Venus is the brighter of the two, with Saturn just above it.

The Suits-Bueche Planetarium at the Schenectady Museum, is currently closed, and will re-open again on October 29^th. During this time, we are installing the new GOTO Chronos Space Simulator Star Machine. A grand opening celebration is currently being planned for the evening of October 28^th.

The arrival of the First Quarter Moon evokes different responses in amateur astronomers. At First Quarter, the Moon is about 8 days old and the terminator is a straight line that divides the Moon exactly in half. Because the waxing Moon will be illuminated to a greater degree each night for the next 8 days, the Moon will appear brighter and it will brighten the background sky accordingly. For those astronomers whose favorite targets are faint, fuzzy objects such as nebulas and distant galaxies, this situation spells trouble, because their favorite objects become washed out by the brightening sky. But, as Galileo discovered 400 years ago, there are great rewards available by simply training your telescope or binoculars on the Moon itself. In particular, near First Quarter, the Moon presents an excellent opportunity for careful observation along the terminator where objects on the dark side of the Moon are about to undergo sunrise. At Last Quarter, objects on the bright side of the terminator are about to undergo sunset.

The 9 day old Moon on Sunday night offers some particularly fascinating features. Close to the northern end of the terminator is a remarkable deep gash in the Lunar Alps, known as the Alpine Valley. About one-third of the way up from the southern end of the terminator, at the edge of the flat-floored Mare Nubium, stands a remarkable long, razor-thin black line known as the Straight Wall, a fault in the lava floor which has generated a cliff about 600 feet high and 80 miles long and which casts the long, straight shadow in the low sunlight. Within a day or two, the Sun will be higher in the lunar sky and the shadow disappears. Each night, new objects appear along the terminator, which makes for ever-changing, fascinating observations. After Full Moon, the Moon will begin to wane, and all of the same objects will appear in reverse order along the terminator except that, this time, their shadows will be cast in the opposite direction.