Skywatch February 2006
 

Skywatch Line Feb. 1, 2006

By Bernard Forman

The Sun sets today at 5:08 PM.  The waxing crescent Moon, in the constellation Pisces, sets at 9:16 PM.  New Moon occurred last Sunday and First Quarter Moon occurs next Sunday.

Saturn, having reached opposition on January 27, is well placed for viewing all night and is a glorious sight.  In the constellation Cancer, the ringed planet is well above the horizon, which enables us to view it through less of the Earth’s atmosphere, thereby affording steadier views.   Moderate size telescopes afford views of three of the rings, as well as the Casini Division separating the two major, outer rings, as many as five moons, and bands on the planet itself, which appears to have a decidedly chocolate color.  Especially when compared to Jupiter, detail on the planet itself is very subtle. 

Speaking of Jupiter, the king of the planets rises at 1:04 AM Thursday morning in the constellation Libra.  At brighter than minus two magnitude, it is already considerably brighter than Saturn even though it does not reach opposition until May.

Mars, to the right of the Pleiades,  in the constellation Aries, has dimmed to less than zero magnitude and is less than nine arc seconds in apparent diameter.  Although high in the sky, Mars has become a disappointing object for telescopic viewing.

At brighter than minus four and a half magnitude, Venus rises in Sagittarius at 5:06 AM Thursday morning.

By 10:00 PM tonight, Andromeda is sinking near the horizon in the west.  From a dark location, the winter Milky Way can be traced from Cassiopeia , through Perseus and Auriga, and past Orion and Gemini.

 Although many associate the constellation Leo, the Lion, with Spring, Leo is now coming readily into view.  An easy way to find Leo is to first locate the Big Dipper.  The pointer stars, Merak and Dubhe, when used to point in the direction opposite  Polaris, points in the general direction of Leo.  A line from Megrez through Phecda, continuing some forty-six degrees across the sky, comes to Alpha Leonis, commonly known as Regulus.  

Skywatch line for Thursday, Feb.2, 2006
by Ray Bogucki

   Today's Skywatch line concludes the descriptions of the stars in the "Winter Oval". Starting with Capella, the brilliant star almost directly overhead, and moving southwesterly about 30 degrees, we encounter two bright reddish objects.  The planet Mars, the more westerly of the two, shines just south of the famous star cluster, the Pleiades, also known as the Seven Sisters.  The more easterly of the two is the first magnitude star Aldebaran, the red eye of Taurus the Bull.  Aldebaran appears to be imbedded in another famous star cluster known as the Hyades, whose V-shape forms the face of the Bull.  Aldebaran is relatively close to us, about 65 light-years away, and is not physically connected to the Hyades which lie twice as far away.  Aldebaran is a red giant star, about 36 times larger in diameter than the Sun.  Its red color arises from the fact that it is a fairly cool star with surface temperature of about 4,000 degrees K, compared to the Sun at about 6,000 degrees. 
  Lying about 25 degrees south of Aldebaran is Rigel, the last star in the "Winter Oval" in the foot of Orion the Hunter.  Rigel is a brilliant, zero-magnitude, blue-white giant.  With a surface temperature of 20,000 degrees K it is 5 times hotter than Aldebaran.  Because it shines at zero-magnitude despite its great distance of 770 light years, we can calculate that it is among the most luminous stars known.
  Standing in stark contrast to Rigel is the bright reddish star Betelgeuse (BET'-el-jooz) which is enclosed by the Oval, in the shoulder of Orion.  Its surface temperature is a cool 3,000 degrees K.  Betelgeuse is a true red supergiant with a staggering diameter 300 times larger than that of the Sun -- roughly the diameter of the orbit of Mars.  If the center of Betelgeuse were placed where the center of the Sun lies, the Earth would be revolving deep inside the star.  If this experiment could be performed, we would find that, because of the incomprehensibly large volume of the star, we would be passing through a medium comparable in density to a high vacuum.  Thus, the stars of the "Winter Oval" challenge our imaginations, from the white dwarf star companion of Sirius, with a density of several tons per teaspoonful, to the red supergiant Betelgeuse, with a density too small to measure.

This is Dudley Observatory's Skywatch Line for Friday, February 3, through
Sunday, February 5.
by Alan French
The Moon, now heading toward first quarter, has moved back into the evening
sky.  As the Sun sets Friday night, the Moon will be high toward the
south-southwest.  This is an excellent time to turn a telescope or binocular
toward the Moon.  Even a pair of steadily held binoculars will reveal some
of the larger craters on our nearest celestial neighbor, and virtually any
telescope will show an amazing amount of detail.
As you explore the Moon with even the most modest telescope, you will see
many craters of all sizes, mountains and mountain chains, and vast "seas,"
which are relatively smooth ancient lava flows.  Before the invention of the
telescope, people though these smoother plains actually were oceans.  They
have kept this designation even though we now know the Moon has no liquid
water.
The Moon is best observed with a telescope when it is near first or last
quarter.  The line between brilliant sunlight and darkness on the Moon is
called the terminator, and as we move from new Moon to full Moon, it is the
sunrise line.  It is along the sunrise line that shadows are longest and
detail stands out in bold relief, and this is where your telescope or
binocular will reveal the most detail.
As the sunrise line marches across the Moon, the higher peaks and crater
rims over in darkness catch the light of the rising Sun first, and appear as
points or arcs of light intruding on the darkness.  It is fun to catch the
first rays of the Sun hitting these features, and then to watch them slowly
emerge into full sunlight.  Although the Moon is an unchanging world, the
rising Sun provides an ever changing view of the beautiful lunar orb.
The Moon will be even higher and more toward the south as the Sun sets on
Saturday night, providing another chance to explore this fascinating world.
On Sunday night, the Moon will be quite close to reddish Mars, which will be
only two degrees below and a bit right of the Moon at 6:00 PM.
Unfortunately, Mars is too far from Earth and too small to provide much
detail though even the best telescopes.  The Moon, however, always provides
something to see.

This is the Skywatch Line for Monday, February 6
by Joe Slomka

 The Sun sets tonight at 5:15 PM with night falling at 6:51 PM. Dawn breaks at 5:27 AM and the Sun rises at 7:03.

As the Sun sets, both the Moon and Mars are seen high in the southeastern sky. Mars is now a smaller, dimmer planet than it was last year.
Mars and the Moon straddle the Pleiades star cluster. In fact, Mars and the Pleiades should share the same binocular field. The Moon, now nine days old, is about two thirds illuminated and washes out most of the objects in its vicinity.

At Sunset, Saturn peeks over the eastern horizon and remains up most of the night. Any telescope will show Saturn's rings, but larger instruments can see four of Saturn's moons after nightfall. If you don't have a telescope, binoculars show Saturn within one degree of the Beehive star cluster.

Jupiter rises shortly after midnight, and by dawn is well placed for observation. Unlike Saturn, Jupiter makes four of its moons available to binocular viewers. Dawn also finds Venus peeking over the eastern horizon. Venus is beginning a short apparition. This month Venus hugs the horizon and is not an easy object.

As the Sun sets, the giant constellation Orion appears. Canis Major, the Big Dog, follows at Orion's heels. Sirius, its brightest star, is among the closest stars to our Solar System, at 8.6 thousand light-years. Although stars seem fixed in our sky, they are actually traveling in different directions and different speeds. Sirius is one of these. In sixty thousand years, it will approach to 7.8 light-years and increase its brightness only marginally. Sirius is not a solitary star; it has a companion, appropriately nicknamed "The Pup." This star closely orbits Sirius once every fifty years. This star is much smaller and dimmer than the primary. Sirius B, as this star is formally called, is still a bit too close. In a few years, amateur telescopes may spot The Pup, once Sirius' brilliance is blocked. Sirius B is about the Earth's size, but has the Sun's mass.

    This is the Dudley Observatory Skywatch Line for Tuesday, February 7th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

   Sunrise today was at 7:04 AM, and it set tonight at 5:15 PM.

   The Moon today is in a Waxing Gibbous phase, with the Full Moon on Sunday, the 12th. It rose today just before Noon, and set at around 4:30 tomorrow morning. Look for the almost Full moon on the evening of the 10th and the 11^th, in the vicinity of the Planet Saturn.      

    The planet Mars, looking like an orange-yellowish star, is visible high up in the south west, as soon as darkness falls. It is near the star cluster known as the Pleiades, otherwise known as the Seven Sisters.

    At the same time, the planet Saturn is high up in the south east. It is in between the constellations of Gemini and Leo. This is still one of the best objects to see in a small telescope, as just 30 power will reveal its ring system. 

    For those who like to stay up very late, or get up very early, the Planet Jupiter rises after midnight, and is also visible about an hour or so in the southeast before Sunrise. The bright planet Venus is in the east southeast before Sunrise.

    The Winter constellations are high up in the south by 9:30 PM.  Look for Orion the Hunter by spotting the three stars in a row that mark his belt.  A line drawn down from the belt points to the brightest star in the entire nighttime sky, the “dog star” Sirius.

    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 “Cowboy Astronomer”, and at 3 P. M. is a live narration of the Winter Sky.  “Cowboy Astronomer” also plays Tuesday through Fridays at 2 PM.

Skywatch Line for Wednesday, Feb 8, 2006
by Bernard Forman

Today sunset is at 5:18 PM.  The waxing gibbous moon rises at 12:43 PM and sets tomorrow morning at 5:16 AM.    First quarter moon occurred last Sunday and full moon occurs next Sunday night.

Should we be so fortunate as to have clear weather, the bright gibbous moon will wash out much of the sky, leaving the Moon and Saturn as available objects of interest.  Of course Saturn, being just past opposition, is a prime target for many an amateur’s telescope.

If you can imagine a line, from Mars, on the border between the constellations Aries and Taurus, the Moon on the constellation border between Gemini and Auriga, then on to Saturn in Cancer, you have now found a part of the path which the Sun appears to follow in the sky, commonly called the ecliptic.  Of course, it isn’t the Sun’s motion that makes it seem to move but, rather, the Earth revolving in its orbit around the Sun.  Where, exactly, is the ecliptic?

First, recall that we find Polaris, the pole star, approximately 42 ½ degrees above the northern horizon from our location on Earth.  The height of Polaris above the northern horizon is equal to the observer’s latitude.  If you stood on the north pole, Polaris would be directly overhead.  If you stood on the equator, Polaris would be on the horizon.  Since the celestial equator is exactly 90 degrees from the north celestial pole, at its highest point due south the celestial equator is 90 minus 42 ½ or 47 ½ degrees above the horizon.  The height of the celestial equator, and the angle it makes with the horizon, are dependent on the observer’s latitude.

What about the ecliptic?  The orbit of the planets, including the Earth, may all be found in a plane centered approximately along the ecliptic.  This fact is, no doubt, due to the manner in which the Sun and its system of planets formed.  The Earth’s axis is tilted 23 ½ degrees from the plane of the ecliptic.  Accordingly, the ecliptic crosses the celestial equator at an angle of 23 ½ degrees.  When the Sun, like the stars, is above the celestial equator in the sky, it is above the horizon more than 12 hours, and when it is below the celestial equator, it is above the horizon for fewer than 12 hours.  That fact, and the differences in the angle of the Sun’s energy falling on the Earth, results in the seasons.

For observers in the northern hemisphere, the observable nighttime ecliptic, when at its highest, occurs in the Winter.  Accordingly, the best planetary oppositions, that is, the best times to view the planets beyond the Earth, occur (for northern hemisphere observers), in the Winter.  Accordingly, this opposition is an especially good opportunity to study Saturn.

If these concepts are difficult to imagine, look at a planisphere, which plots both the celestial equator and the ecliptic.  Notice where they cross and which time of year the ecliptic is highest above the celestial equator. 

You are now well on your way to understanding how the nighttime sky works.

Skywatch line for Thursday, February 9, 2006
    The path of the Moon across the night sky this week presents several interesting aspects.  Last Sunday, the first-quarter Moon passed close to Mars, and a few hours later, through some of the more southerly stars of the large Pleiades cluster in Taurus, heading toward beta Tauri.  This star defines the point of the northern horn of Taurus, and is usually also included in the pentagonal asterism of Auriga.  Beta Tauri bears the Arabic-derived name El Nath, the "butting one".  The Moon's edge as seen from here just skimmed past El Nath in a near miss, but Mexican observers actually saw the edge of the Moon occult the star.  Last night, the Moon reached its highest, or northernmost point in its orbit.  Observers in the southern parts of Florida and Texas saw the Moon pass directly overhead.  At our latitude, the Moon never gets higher than about 76 degrees above the southern horizon.
  Tonight, the waxing gibbous Moon will glide closely past the first-magnitude star Pollux, in the constellation Gemini, heading toward the bright, ringed planet, Saturn, in Cancer the Crab.  Early Saturday morning, the nearly full Moon will lie just to the right of Saturn, low in the northwest. Saturn still lies just a couple of Moon-widths south of the elegant bright star cluster known as the "Beehive".  Binoculars or a small telescope will show the planet and the cluster in the same field of view.
  On Sunday night, perceptive observers may notice that the full Moon appears a bit smaller than usual.  That is because the Moon is at apogee, its farthest distance from the Earth in this lunar cycle. It is also the farthest apogee of the thirteen that occur this entire year, at 252,560 miles.  This makes it appear 12% smaller  than it appears at  perigee, its closest approach in its elliptical orbit.
  Finally, for early risers, crescent-shaped Venus is now at its brightest at magnitude minus 4.6, climbing into the eastern sky at the onset of morning twilight, while Jupiter, at magnitude minus 2.1, shines high in the south.

Skywatch line for Thursday, February 9, 2006
by Ray Bogucki
    The path of the Moon across the night sky this week presents several interesting aspects.  Last Sunday, the first-quarter Moon passed close to Mars, and a few hours later, through some of the more southerly stars of the large Pleiades cluster in Taurus, heading toward beta Tauri.  This star defines the point of the northern horn of Taurus, and is usually also included in the pentagonal asterism of Auriga.  Beta Tauri bears the Arabic-derived name El Nath, the "butting one".  The Moon's edge as seen from here just skimmed past El Nath in a near miss, but Mexican observers actually saw the edge of the Moon occult the star.  Last night, the Moon reached its highest, or northernmost point in its orbit.  Observers in the southern parts of Florida and Texas saw the Moon pass directly overhead.  At our latitude, the Moon never gets higher than about 76 degrees above the southern horizon.
  Tonight, the waxing gibbous Moon will glide closely past the first-magnitude star Pollux, in the constellation Gemini, heading toward the bright, ringed planet, Saturn, in Cancer the Crab.  Early Saturday morning, the nearly full Moon will lie just to the right of Saturn, low in the northwest. Saturn still lies just a couple of Moon-widths south of the elegant bright star cluster known as the "Beehive".  Binoculars or a small telescope will show the planet and the cluster in the same field of view.
  On Sunday night, perceptive observers may notice that the full Moon appears a bit smaller than usual.  That is because the Moon is at apogee, its farthest distance from the Earth in this lunar cycle. It is also the farthest apogee of the thirteen that occur this entire year, at 252,560 miles.  This makes it appear 12% smaller  than it appears at  perigee, its closest approach in its elliptical orbit.
  Finally, for early risers, crescent-shaped Venus is now at its brightest at magnitude minus 4.6, climbing into the eastern sky at the onset of morning twilight, while Jupiter, at magnitude minus 2.1, shines high in the south.

Skywatch Line for Friday, February 10, through Sunday, February 12
by Alan French

The Moon will be Full just before midnight on Sunday night, so the weekend
skies will be dominated by bright moonlight.  The Moon will be at perigee –
its farthest distance from the Earth– less than one day after Full, so this
will be the most distant Full Moon of the year.  The New Moon this month,
which occurs on February 27, will be just hours after the Moon is at
apogee – its closest approach to the Earth – so tides will be unusually high
then.
The full moon makes it difficult to see faint celestial objects.  Contrary
to popular belief, this is not even a good time to observe the moon.  If you
were standing right in the middle of the visible part of the moon tonight,
the Sun would be high in your sky.  Just as on the Earth, when the Sun is
high, shadows are very short.  It is mostly the shadows cast by the
mountains and craters on the Moon that make them stand out in bold relief;
so when the Moon is full it has a washed-out look, and details are not as
obvious.
However, there is one type of lunar feature that is easiest to see now.
Some of the younger craters on the Moon have bright rays of material
radiating out from them.  This is debris that was scattered across the Moon
when the impacting objects that made these craters struck.  Solar radiation
slowly darkens moon dirt, so these ray systems eventually disappear.
Binoculars will easily show the brightest system of rays.  They stream out
from the crater Tycho (TIE-koh) which is located in the south central part
of the Moon.  Some of these rays extend one-third of the way across the face
of the Moon.  Tycho is a relatively young crater, about a half billion years
old.  Most of the other features visible on the Moon are about six times
older.
If you are up early on Monday morning, you will have a fine chance to watch
the International Space Station pass right overhead.  When it rises high in
the sky, the ISS rivals the brightest stars, and its movement across the sky
makes it easy to spot.
On Monday morning, the ISS will appear above the northwestern horizon just
after 6:05 AM.  It will pass directly overhead at 6:07:35, and will vanish
below the east southeastern horizon three minutes later.  We see the ISS
because it is up in the light of the rising Sun, while we are still down in
the Earth's shadow waiting for the Sun to rise.  Sunrise is now just before
7:00.

This is the Skywatch Line for Monday, February 13.
by Joe Slomka

The Sun sets at 5:24 PM, with night falling at 7 PM.  Dawn breaks at 5:19 AM, ending with sunrise at 6:54.

At sunset, Mars glows brightly high in the South, while Saturn rises out of the East. Mercury can be spotted low in the West, but it is very low, and may be hidden by trees and buildings. Only Saturn gives satisfying views of the planet close to the famous Beehive star cluster.

By nightfall, the Moon, now one day past "Full," rises from the East, underneath Leo, the Lion. The Moon's brilliance washes out most dim objects, but not Saturn or the Beehive in binoculars.  Mars is also far enough from the Moon to permit binocular views of it and the nearby Pleiades star cluster in the same field of vision.

Jupiter rises after Midnight, and lies in the midst of the dim constellation Libra. Jupiter never gets very high in our skies and seeing detail may be a challenge on less than perfect nights.

Sunrise has Venus joining Jupiter. Venus is low in the East; Jupiter is higher in the South.

If one looks up at 7:00 PM on a moonless night, the Hyades star cluster is high and forms the horns of Taurus, the Bull.  The "V" shaped constellation points to a large pentagon, the constellation AURIGA.  If the "V" is extended, the upper horn joins the bottom star of Auriga.  The lower horn stops at a star just below.  Train a telescope at that lower star, and look just above it.  The hazy patch is the Crab Nebula.  On July 4, 1054, a star exploded, shone brightly in daytime, and disappeared after about a year.   The Crab Nebula is all that is left, a cloud of gas and debris, expanding at 600 miles per second, with a diameter of 6 light years and 6300 light years distant.  Recent studies revealed that the remnant star emits radiation in regular bursts. This radiation lights up the neighboring gas in infrared light.  This is the most conspicuous supernova remnant.

Skywatch Line for Feb 15, 2006
by Bernard Forman

Today, the sun sets at 5:27 PM.  The waning gibbous moon rises in the constellation Virgo at 8:00 PM, full moon having occurred late last Sunday and first quarter moon occurring next Tuesday.

Looking high up in the west Mars is still prominent in the constellation of Taurus between zero and first magnitude.  Saturn, brighter than zero magnitude in the constellation of Cancer, transits before 11:00 PM.  Jupiter, at brighter than minus two magnitude, rises after midnight in the constellation Libra.  Finally, Venus rises at 4:27 AM Thursday morning in the constellation Sagittarius.  Venus is especially brilliant, at brighter than minus four and a half magnitude.

With the moon being just a few days past full and above the horizon most of the evening, its light seriously impedes our view of the nighttime sky, washing out all but the planets and the brighter stars.  To many amateur astronomers, whose main interests are in observing faint, deep sky objects, the moon is a form of light pollution.  However, the rising and phases of the moon are predictable, and the nights around new moon and first quarter afford us evenings of dark skies unless, of course, we must contend with man made light pollution.

A recent trip to Florida demonstrated, once again, the fact that much outdoor nighttime lighting is poorly designed and unnecessarily extensive.  From the vantage point of several thousand feet above the ground, lights can be seen shining upward, where it only serves to illuminate the sky.  Around the capital district it is easy to trace the extent of the cities and the expanding suburbs.  Around New York City and southern Florida, the lights appear to extend even beyond the horizon.

Lighting which is not properly designed by aiming light downward does more harm than just destroying our view of the nighttime sky.  It also wastes energy and impairs our ability to see at night by shining into our eyes.  It may also harm flora and fauna.

Good outdoor lighting is in everyone’s best interests.

Skywatch line for Thursday, February 16, 2006
by Ray Bogucki

   For the next few weeks, Orion, arguably the most magnificent constellation anywhere in the sky, will sparkle brilliantly in our southern sky in the early evening.  The constellation is easily recognized by the four bright stars in a roughly rectangular arrangement which locate the two shoulders and the two knees (or feet) of the giant.  Across the center of the rectangle lie 3 bright white stars in a line which denote the giant's belt.  Three fainter stars forming his sword dangle downward from the left end of the giant's belt.  Because it lies astride the celestial equator, Orion is visible from all inhabited places on the planet.
  This constellation is impressive by any measure.  All seven of the stars forming the rectangle and the belt are giant stars, typically thousands of times more luminous than our Sun.  They are moderately far away with distances ranging from 250 to 1350 light years.  Most are clustered near 800 light years away.
  Studies of the shifts in spectral lines indicate that they are all moving away from us with speeds in the neighborhood of 13 miles per second, or about 400 million miles per year.  Combining their distances and speeds of recession, we can calculate that 10 million years ago, they were much closer to our solar system and would have been shining in our night sky with much greater brilliance than that current eye-burner, Venus, now at its greatest brilliance in the southeast in the early morning twilight.
  The less obvious sword, hanging from the belt is no less impressive.  Even the naked eye can detect that the middle star of the three in the sword is actually a fuzzy patch of light.  Binoculars show it as a distinctly shaped nebulosity.  A small telescope reveals a nebulous cloud with an upswept appearance, as if it were being blown about by interstellar winds.  In one corner of the cloud is a bright spot which, with adequate magnification, is seen to be a small trapezoidal shaped cluster of 4 bright stars known as the Trapezium.  These are infant stars which have just recently been born in the vast cloud of gas and dust that forms the nebula.  Indeed, the nebula is a giant stellar nursery with many new stars currently in the process of being formed.
    Incidentally, the sight of Venus deserves an early rising.  It is currently a beautiful, 25% illuminated crescent somewhat larger than the apparent disk of Jupiter.

Tonight, the Sun sets at 5:36 PM.  The waning crescent moon doesn’t rise until  3:46 AM Thursday morning, so we should have dark skies for most of the night.  New moon occurs next Monday. 

On Friday, Mercury is at greatest elongation east of the Sun, so now is an excellent time to view Mercury just after sun set.  Since Venus is a morning object, visible before dawn, there will be no confusing Mercury with Venus.  Look for Mercury close to the western horizon just after sun set.

Starting with Mercury, all the naked eye planets can be viewed during the night.  Mars, growing ever smaller and dimmer, is in Aries, northeast of the Pleiades and well to the west of Aldebaran.  Next is Saturn in the constellation Cancer, followed by Jupiter rising around midnight in Libra and brilliant Venus, visible before dawn in Sagittarius.

Of course, the winter constellations are on display and most prominent among them, in fact one of the most prominent of all constellations, is Orion, the Hunter.  Orion contains one of the most glorious of objects, the Great Orion Nebula, an object which receives considerable scrutiny from amateur astronomers as it is a beautiful object no matter the instrument, binoculars or telescope, used to view it.  But Orion contains other objects of interest.

Betelgeuse, or Alpha Orionis, is actually the second brightest star in Orion, after Rigel, or Beta Orionis.  A red super giant, Betelgeuse is so big that, if placed in our Sun’s location, its outer atmosphere would extend past Jupiter.  It is so large that it is the first star to have its surface directly imaged. 

Betelgeuse is a high mass star in an advanced stage of evolution.  Generally, the greater a star’s mass, the faster it converts hydrogen into helium.  Betelgeuse has spent its supply of hydrogen so its core, which is now fusing helium into oxygen and carbon, has contracted, and its exterior has swelled.  Eventually, because it is so massive, it will create heavier elements, including iron, after which it will either explode as a nova, leaving a neutron star, or become a white dwarf.

The universe is still predominantly made up of hydrogen and, what heavier elements now exist, were formed in massive stars long since exploded.  One day a million or more years from now, Betelgeuse will add its heavier elements to the universe.

Skywatch line for Thursday, Feb. 23, 2006
by Ray Bogucki

     In the upcoming week, Mercury, the Sun's innermost planet, will put on its best apparition as an evening star this year.  Mercury is only a bit larger than our own Moon, and revolves around the Sun at an average distance of 36 million miles with an orbital period of only 88 days.  Because of its tight inner orbit, Mercury never appears very far from the Sun in our sky.  Tonight, Mercury is at its farthest point east of the Sun and thus at its highest point in the western sky after sunset.  To see Mercury, find a location with an unobstructed view of the western horizon.  About a half hour after sunset, as twilight is fading, look for a bright, star-like object low near the western horizon.  There is no other bright object in that part of the sky, so the planet is fairly obvious.  Binoculars will help.
  A small telescope will show Mercury as a small disk about 50% illuminated by the Sun, looking like a smaller version of the first quarter Moon. Each night, as the planet overtakes us in its faster orbit, the disk will appear a little larger, the illuminated phase will become a thinning crescent, and the planet will drop lower in the West.  By early march, Mercury will have approached close enough to the Sun to be lost in its glare.  On March 12, it will pass between us and the Sun at inferior conjunction and a couple of weeks later it will begin to appear low in the eastern sky just before sunrise as a morning star.
  On Monday, the Moon will pass between the Sun and the Earth to generate the new Moon, the beginning of the next lunar cycle.  The gravitational pull of both the Sun and the Moon have an effect on the tidal bulge in the Earth's oceans.  At full Moon and new Moon, the gravitational effects of the Moon and Sun work in concert to produce a heightened bulge, and especially high and low tides known as spring tides (nothing to do with the season).  Monday's new Moon is special because it occurs when the Moon is at perigee, its closest approach to the Earth in its current cycle.  Moreover, it happens to be the closest perigee for this entire year.  The extra closeness of the Moon will enhance its gravitational effect to produce unusually high spring tides known as perigean spring tides.  If you live near an ocean beach, check the height of the tides this Monday and Tuesday.  They should be extraordinary.  If the perigean spring tides coincide with the landfall of a major storm the heightened storm surge can be devastating.

Skywatch Line for Monday, February 27, 2006.
by Joe Slomka

The Sun sets tonight at 5:42; night falls at 7:16. Dawn breaks at 4:59 tomorrow morning, ending with sunrise at 6:33.

At sunset, Mars shines brightly high in the South. Mars is now a shadow of itself a year ago, and not much for amateurs to look at. However, the Mars rovers continue their exploits and provide scientists a detailed picture over the course of a Martian year.

Mercury shines brightly low in the West and sets at nightfall. Binoculars help finding this elusive planet. Observers have a better chance of seeing Saturn. Saturn is quite high and remains up for most of the night. Saturn remains close to the Beehive star cluster and presents a great image in binoculars.

Jupiter rises about midnight and remains up. It occupies the low and dim constellation Libra, the Scales. Dawn finds Venus joining Jupiter.
By sunrise, both are high and bright, stretching from southeast to South.

Polaris, the Pole or North Star, is one of the most famous of all stars. Many people think that it is the brightest; it is not, only second magnitude. Its importance is an accident of place; Polaris happens to occupy the spot closest to true North. In a few thousand years, it will drift away, and another star will become the Pole Star. Many do not know that it is a multiple star system. Using the Hubble Telescope, astronomers recently discovered a third member. By analyzing the stars' orbits, they "weighed" Polaris, and found it about four times heavier than our own Sun. However, Polaris has one distinction. Not many people know that it is a variable star; it periodically brightens and dims. Polaris is a Cepheid variable, in fact it is the brightest of its kind in our sky. Cepheids are valuable stars. The period of their variation is in direct ratio to their brightness. So if an observer sees a Cepheid and tracks its cycles, he can determine its  intrinsic brilliance and also derive its distance from us.

    This is the Dudley Observatory Skywatch Line for Tuesday, February 28th, 2006, written by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

   Sunrise today was at 6:36 AM, and it set tonight at 5:46 PM.  Sunrise tomorrow will be at 6:34 AM and Sunset will be at 5:47 PM.

   The Moon was in New Moon phase yesterday, so a thin waxing crescent might be seen this evening.  It will set at 6:50 this evening, shortly after the Sun. Tomorrow the Moon will set at 8:07 PM.  Look for the planet Mercury just below the Moon.      

    The planet Mars, looking like an orange-yellowish star, is still near the star cluster known as the Pleiades, otherwise known as the Seven Sisters. The Moon will be near Mars on Sunday evening.

    At the same time, the planet Saturn is high up in the south east. It is in between the constellations of Gemini and Leo.  

    The Planet Jupiter rises around midnight, and is also visible about an hour or so before Sunrise in the south. Venus, the brightest object in the Solar System after the Sun and the Moon, is in the east at around 6:00 AM.  It is the only planet that can be viewed during the day.

    The Winter constellations are high up in the south by 9:00 PM.  Look for Orion the Hunter by spotting the three stars in a row that mark his belt.

    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 “Cowboy Astronomer”, and at 3 P. M. is a live narration of the Winter Sky.  “Cowboy Astronomer” also plays Tuesday through Fridays at 2 PM.

Skywatch Line for March 1, 2006
by Bernard Forman

The Sun sets tonight at 5:44 PM.  The waxing crescent moon, in the constellation Pisces,      rises at 7:25 AM and sets at 8:07 PM.  Mercury precedes the moon toward the horizon, setting at 7:08 PM.  Look for Mercury near the western horizon after sunset.

While Mars is easily visible near the Pleides in the constellation Taurus, the Bull, it is well past opposition and a disappointing target for amateur telescopes.  Far more interesting is Saturn, shining at brighter than zero magnitude in the constellation Cancer, the Crab, near M 44, the Beehive Cluster.  Both will be visible in the same field of view in ordinary binoculars.  In a modest size telescope, Saturn will display its glorious rings, perhaps some detail on the ball of the planet, and several moons.  At 10:00 PM tonight, looking through a Newtonian telescope, Enceladus will be to Saturn’s left, with Rhea below and slightly to the right of Enceladus.  Both will appear relatively close to the rings, as will Dione and Tethys to Saturn’s right.  Much further to the right will be Saturn’s largest moon, Titan.  A Newtonian telescope has an inverted view, with West to the left, and North at the bottom.  If you are using a telescope with an odd number of mirrored surfaces, the view is mirror reversed, with North at the top and East to the right.

Jupiter rises in Libra at 11:21 PM and is well placed before dawn.  Jupiter is brighter than minus two magnitude and is, in many ways, the most interesting planet for amateur telescopes, as it shows the most detail on the ball of the planet, and the four Galilean moons can be followed in small telescopes.  Unlike the moons of Saturn, the Galilean moons, and their shadows, often transit, or pass in front of, the planet.  At 10:00 PM tonight, only three of the moon, Io, Ganymede and Callisto will be visible, as Europa will be behind Jupiter.  In a Newtonian telescope, look for Ganymede far to the left of Jupiter, Callisto just below the planet, and Io to Jupiter’s right.

Finally, if you want to see the remaining naked eye planet, Venus, you will have to get up before dawn.  Brighter than minus four and a half magnitude, Venus rises at 4:09 AM east of the Teapot asterism in Sagittarius.

And with the crescent moon setting early, don’t forget to go hunting for some deep sky objects. 

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Dudley Observatory
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