Skywatch July 2004

 Skywatch Line for Wed. July 7, 2004  by Ray Bogucki
  Of the five bright planets, only Jupiter is readily visible in the evening sky.  It shines at the bright magnitude of minus 1.8, low in the west in the constellation Leo at nightfall.  Two other planets, Mars and Mercury, are also in the western sky but much lower than, and to the west of, Jupiter.  Since our spectacular close approach to Mars last August, at a distance of only 35 million miles, the Earth has moved steadily away from Mars until we now stand at opposite ends of our orbits at a distance of 237 million miles apart.  The apparent disc of Mars, which was 25 arc-seconds in diameter last August, has shrunk to 3.7 arc-seconds, the same size as the distant gas giant, Uranus. 
  By a happy coincidence, the innermost planet Mercury, having swung around behind the Sun, is now approaching Earth rapidly and appears in the sky very close to Mars.  To observe these two planets, find a location with an unobstructed view of the western horizon, and search very low in the west with binoculars about 40 minutes after sunset.  Tonight, reddish Mars will be a little above and to the left of white Mercury. Each evening Mercury will appear to move closer to Mars until Saturday, when Mercury will be directly above Mars at a separation of only 10 arc-minutes, the closest planet-to-planet conjunction of this year.  A direct visual comparison of the two close planets is interesting.  Although Mars' physical diameter is 40% larger than the diameter of Mercury, Mars will appear much smaller because it is more than twice as far away.  For the same reason, Mercury will appear 8 times brighter than Mars.
  Saturn, which was the center of attention last week when the spacecraft Cassini-Huygens was inserted into a highly elliptical orbit around the ringed planet, is now passing behind the Sun and cannot be observed visually.  Fortunately radio waves are easily transmitted and received during this period so information from Cassini continues to flow.
  Finally, the brightest planet, Venus, having performed a rare transit across the Sun's face just a month ago, has now emerged into the morning sky, rising about 90 minutes before sunrise.  It stands very close to, and just to the left of Aldebaran, the reddish star that marks the eye of Taurus the Bull.  Because it is still very close to us at just 37 million miles, and because most of the sunlight falls on the side of Venus away from us, a telescope or even binoculars show it as a beautiful, large, thin crescent.  Next Tuesday and Wednesday mornings, the waning crescent Moon will swing close to the waxing crescent Venus.

Skywatch Line for Friday, June 9, through Sunday, June 11, 2004 by Alan French

On Saturday night residents of the Capital District will have a fine chance to see the International Space Station pass over our area.  At its brightest it will rival the brightest stars in the evening sky.  The ISS will appear just after 10:06 PM above the southwestern horizon.  It will gradually rise higher into the night sky, becoming brighter and easier to spot.  It will be highest just after 10:09 PM when it will be 68 degrees above the southeastern horizon.  If you missed the ISS when it was first rising into the night sky, look for a bright star very high in the southeast moving toward the east-northeast at 10:09.  The ISS will vanish below the east-northeastern horizon just after 10:12 PM.

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, the amateur astronomers typically point their telescopes at some of the best celestial showpieces.  Later on, they will be happy to take requests - provided, of course, the object is above the horizon and visible in amateur telescopes.

Friday night's program is at the George Landis Arboretum in Esperance, and begins 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.

Saturday night's Star Party is in Indian Meadows Park in Glenville, also beginning at 10:00 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.

There is no admission charge and all ages are welcome.  Star Parties are canceled if the skies are mostly cloudy.  Call Alan or Sue French at 374-8460 for more information.

Skywatch line for Wed., July 14, 2004 by Ray Bogucki
  The long range weather forecasts for the coming week suggest that most nights will be cloudy and unsuitable for visual observation of the night sky.  This situation presents the opportunity to reflect on how much astronomy goes on even when the stars are not visible to the casual observer.  From the earliest times, when primitive humans began to ponder the significance of the Sun, Moon, stars and the few nebulas and galaxies visible to the unaided eye, all of the information came to human eyes in the narrow band of electromagnetic radiation known as visible light. In 1609, Galileo first began observing the night skies through a telescope, and the rapid advance of optics allowed observers to see greatly enlarged images and much more detail in celestial objects, but still only in visible light.  But the electromagnetic spectrum is very broad and includes, in order of higher frequencies or shorter wavelengths, the broad categories known as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays.  The radio waves are at the lowest energy end of the spectrum while gamma rays are the highest energy radiation.
  Most celestial objects transmit energy in several of these categories and, over the past century, scientists and engineers have developed sensors that can receive and interpret these signals.  This has led to an explosive expansion of the information available to modern astronomers.
  For example, radio waves transmitted by the Cassini spacecraft orbiting Saturn, or by the Mars rovers, carry information that is decoded here on Earth and reconstituted as the glorious images we see on the web or in papers and magazines.  The development of microwave detectors led to the Nobel Prize-winning discovery of the remnant radiation of the Big Bang that suffuses our Universe. Infrared and radio detectors allow us to penetrate the extensive gas and dust clouds that visually obscure the center of our galaxy and lead to the startling conclusion that the hub of our galaxy is probably powered by a huge black hole.  Because high-energy ultraviolet and gamma radiation are largely blocked by our atmosphere, NASA launches satellites to orbit high above our gaseous blanket and study high energy radiation from our Sun and much more distant objects such as quasars and short-lived gamma ray bursters, which may be associated with the cataclysmically explosive deaths of supergiant stars.  Even on cloudy nights, with observatories closed, the information gathered from all parts of the electromagnetic spectrum pours in.  It's a great time to be an astronomer!

Skywatch Line for Friday, July 16, through Sunday, July 18, 2004  by Alan French

One of the most awe-inspiring astronomical sights visible in our area is a display of the Aurora Borealis or Northern Lights.  We never really know when there will be northern lights.  Some people feel that they favor the time of year near the equinoxes.  But the only way to make sure that you see one of these magnificent displays is to gaze north whenever you’re under a clear, dark sky.  There has been some increase in solar activity lately, so it is good to keep your eyes open.

     A complicated and not completely understood process causes Northern Lights.  Our Sun is a violent place with huge eruptions and storms.  These storms send solar particles far into space, and some end up trapped in the Earth’s magnetic field.  When the field is overloaded, charged particles can rain down onto the Earth’s atmosphere in an oval around the Earth’s magnetic poles.  The electrically charged particles from the Sun make the air glow in much the same way that the gas inside a neon light glows.  And like neon lights, auroras come in many colors.

     We live too far south to see some of the vividly colorful auroras that are sometimes visible in Alaska or northern Canada, but bright colors are occasionally visible here too - mostly various shades of red.  No picture can convey the beauty of the Northern Lights.  They are a highly dynamic phenomenon.

     A typical display starts as an amorphous glow low along the northern horizon.  As the aurora grows it may develop shafts reaching high into the sky.  The horizon glow may begin to fold in on itself creating a diaphanous curtain of light in the sky.  During a good display, the aurora can climb high overhead in a display known as a zenith aurora or corona.  The corona can take on astonishing shapes, and once it develops you may even see Northern Lights extending into the southern sky.

     The aurora is always changing.  The curtains wave, the shafts grow and shrink, and subtle colors play across the sky.  The motion may be slow or rapid.  Sometimes the Northern Lights seems to flame like the rapidly rising tongues of a fire gone wild.

     Keep your eye on the north at night and if you’re lucky, you’ll be treated to a sight you’ll never forget.

  Skywatch Line for Tuesday, July 20th, 2004 by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

    The sun will set tonight in the west northwest at 8:28.  It will rise in the east northeast on Wednesday at 5:37 and set in the west northwest at 8:28.  Now that we are past the first day of Summer and the longest days of the year, we are currently losing about 1 minute a day of daylight.  Although this is not much, all of those minutes will add up over a month’s time.  Since the first day of Summer, we have lost around 20 minutes of daylight.  The Moon is currently in a Waxing Crescent phase, rising at about 8:28 PM this morning, and setting at around 10:30 tonight.  It will rise again at around 930 tomorrow morning, and set at around 11PM tomorrow night.  

    Planet viewing is now at a minimum. Very, very low in the west you can locate the Red Planet, Mars.  But after darkness, it is too low to be seen without great difficulty. Jupiter, is very bright, and is low in the west by 9:30 PM.  It is located in the constellation of Leo the Lion.  Tonight, it will be near the Moon.

    Jupiter is good to view even in a small telescope of around 40 power.  At that low magnification, any number of the 4 Galilean Moons can be seen, and if the air is clear, the North and South Equatorial cloud Bands and the Great Red Spot are visible.

    Also during the Spring, look for the Big Dipper high overhead towards the north.  Using the two stars on the end of the cup, draw an imaginary line away from the top of the cup, and it will point you to the North Star known as Polaris.

    In the northeast, the famous Summer Triangle is getting higher up in the sky each night.  It is marked by the three bright stars of Vega, Deneb, and Altair.  They are the brightest stars in the constellations of Lyra the Harp, Cygnus the Swan, and Aquila the Eagle.  The Summer Triangle is high up in the east by 10 PM.

    Public Programs at the Suits –Buech Planetarium at the Schenectady Museum are on Saturdays and Sundays at 1, 2, and 3 P. M.  The 1:00 program is Visit to the Moon, a program for young people. At 2 P. M. is W S K Y, a program about almost everything in the universe, revolving around a fictional radio station. And at 3 P. M. is a live narration of the Summer sky. Updates from the Cassini Spacecraft on its way to Saturn will also be presented.

    And don’t forget, that tonight marks the 35^th anniversary of the first manned Moon landing.

   Skywatch line for Wed., July 21, 2004 by Ray Bogucki
  Skywatchers are now fully involved observing the constellations of midsummer, a season that brings advantages and disadvantages.  A major disadvantage is caused by the late sunset and early sunrise, which produces little more than 5 hours of full darkness for observing.  On the other hand, temperatures are much milder, inviting astronomers to linger longer under the stars.  Another advantage is that this season brings us the glorious southern Milky Way which houses the bulging center or hub of our galaxy.  The bright constellations Scorpius and Sagittarius, now shining low in the south contain a veritable treasure trove of spectacular nebulas and star clouds and clusters embedded in the bright strands and knots of starry light in this region.  Those familiar with skywatchers in this northern temperate zone might notice that they are constantly seeking viewing sites with an unobstructed view to the south.  The reason for this is interesting.
An observer standing anywhere on the Earth on a clear, dark night will see, in the celestial hemisphere above, roughly one-half of the stars visible from Earth.  The other half is hidden by the surface of the Earth itself.  The specific stars that are visible will depend on where the observer stands.  At the north pole, our observer will see only the stars in the northern celestial hemisphere, regardless of the time of year.  Polaris will be overhead and each star will always appear at the same altitude and move from east to west parallel to the horizon.  The stars in the southern hemisphere never appear above the horizon.
   For an observer at the equator,  the north and south celestial poles will lie on the horizon and, over the course of a year,  all of the visible stars in both hemispheres will pass in review.
  At our latitude, in the capital region, we live about halfway between the equator and the north pole.  As a result, the star Polaris, marking the celestial north pole, will shine in the north about halfway between the horizon and the zenith.  The celestial equator will rise from the eastern horizon to about 45 degrees at its highest point in the south and disappear at the western horizon, defining a segment of southern sky shaped like a slice of melon.  While northern observers can view the northern constellations at almost any time of year, those sparkling gems south of the celestial equator, such as Scorpius and Sagittarius, appear for a short period in our evening skies, only in that low segment of the southern sky and only at the particular time of year when the tilt of Earth's rotational axis rotates that section of sky into view.                     

 Skywatch Line for Friday, July 23, through Sunday, July 25, 2004 by Alan French

As a youngster, I saw some of the earliest manmade objects orbiting the Earth as artificial satellites.  I know my father and I looked for Sputnik, but I do not recall if we saw it or not.  I do recall seeing Echo 1.  Today anyone spending time out under the stars is almost certain to notice satellites moving across the night sky.  They appear as moving stars, taking several minutes to cross the sky.  Some rival the brightest stars, while others are barely visible, and they may move directly overhead, or never venture far from the horizon.

    The International Space Station appears as bright as the brightest stars when it travels high in the sky, and is bright enough to spot easily even when its path never takes it far from the horizon.  This weekend we have good chances to see the ISS in the evening sky each night.

    On Friday night, the ISS will appear at 10:00:49 PM rising from the northwestern horizon.  I generally find I spot the ISS a bit later than the time given for "first appearance."  The ISS will be highest at 10:03:36 PM when it will appear 36 degrees above the north-northeastern horizon, and it will vanish into the Earth's shadow at 10:05 PM.

    Saturday night's pass will be the highest of the weekend.  Watch for the ISS to appear just after 10:29 PM above the west-northwestern horizon.  It will be highest just after 10:32 PM when it will be 74 degrees above the west-southwestern horizon – essentially overhead.  Be sure to be watching then, because it will move into the Earth's shadow and fade away just at it reaches its highest point in the sky.

    Sunday night's pass will be earlier, so the sky will not be as dark, and lower, so the ISS will not appear as bright, so it may be a bit harder to spot.  Look for the ISS rising from the northwestern horizon at 9:22:27 PM.

It will be highest at 42 degrees above the north-northeastern horizon at 9:25:18, and will vanish into the Earth's shadow just above the eastern horizon at 9:27:38 PM.

    Let's hope for clear skies, and some nice views of the ISS silently crossing over the capital district!

Skywatch line for Wed., July 28, 2004 by Ray Bogucki
    Directly above, or north of the bright constellation Scorpius lies the larger, but less spectacular constellation, Ophiuchus (off-ih-YOU-cus), the Serpent Bearer, midway up in the southern sky at nightfall.  While ancient astronomers saw the shape of a man holding a serpent, the brighter stars form an asterism that is quite like the shape of an old-fashioned aluminum coffee percolator.  This unassuming constellation has several distinctions.  It contains seven Messier (mess-YAY) objects, all of them globular star clusters.  In 1787, Charles Messier, a French comet hunter, published a list of faint, usually "fuzzy", objects in the night sky which he knew to be fixed in location and thus would not be mistaken for comets, which also appear fuzzy, but which move in predictable ways against the background of fixed stars.
   The last observed supernova to explode in our Milky Way Galaxy appeared in Ophiuchus in 1604 where it remained visible for 18 months before fading from sight.  By a wonderful coincidence, the bright planets, Jupiter and Saturn were close together in Ophiuchus when the supernova suddenly appeared beside them, outshining them both and completely altering the appearance of the constellation.  This star was studied extensively by Johannes Kepler and has become known as Kepler's Star.  In a galaxy such as ours, a supernova appears once every few centuries so we are statistically overdue for our next supergiant to blow itself to bits!
    Far on the other end of stellar dimensions is a tiny red dwarf star discovered near the left edge of the percolator lid by E. Barnard in 1916.  This miniature star is only 20 times the diameter of Earth, and, at magnitude 9.5, is well below naked-eye visibility.  Called Barnard's Star or the Runaway Star, this faint red speck, at 6 light-years, is the second nearest star system to the Sun and, because of its proximity, the apparent motion of this star is the fastest known, over 10 arc-sconds per year.  In a long human lifetime it will have traveled half the diameter of the full Moon.  It is heading in our direction and in a few thousand years it will be closer than alpha Centauri, currently our nearest neighbor at 4.5 light years.

Skywatch Line for Tuesday, July 27th, 2004 by Steven Russo, Planetarium Manager of the Suits-Bueche Planetarium at the Schenectady Museum.

    The sun will set tonight in the west northwest at 8:22.  It will rise in the east northeast on Wednesday at 5:44 and set in the west northwest at 8:21.  The Moon is currently in a Waxing Gibbous phase, and will set after midnight tonight.  It will rise again at around 6:12 tomorrow evening, and set at around 2 AM tomorrow morning.

    Planet viewing is now at a minimum. Very, very low in the west you can locate the planet Mercury.  But after darkness, it is too low to be seen without great difficulty. Jupiter, is very bright, and is low in the west by 9:30 PM.  It is located in the constellation of Leo the Lion.

    Jupiter is good to view even in a small telescope of around 40 power.

At that low magnification, any number of the 4 Galilean Moons can be seen, and if the air is clear, the North and South Equatorial cloud Bands and the Great Red Spot are visible.

    Venus is the bright star-like object in the East Northeast before Sunrise.  However, due to its brightness, it is still visible after 5:00 in the morning.  A small telescope will reveal it in a crescent phase.

    Also during the Spring, look for the Big Dipper high overhead in the north, and slightly towards the west.  Using the two stars on the end of the cup, draw an imaginary line away from the top of the cup, and it will point you to the North Star known as Polaris.

    In the northeast, the famous Summer Triangle is getting higher up in the sky each night.  It is marked by the three bright stars of Vega, Deneb, and Altair.  They are the brightest stars in the constellations of Lyra the Harp, Cygnus the Swan, and Aquila the Eagle.  The Summer Triangle is high up in the east by 10 PM.

    Public Programs at the Suits –Buech Planetarium at the Schenectady Museum are on Saturdays and Sundays at 1, 2, and 3 P. M.  The 1:00 program is Visit to the Moon, a program for young people. At 2 P. M. is W S K Y, a program about almost everything in the universe, revolving around a fictional radio station. And at 3 P. M. is a live narration of the Summer sky. Updates from the Cassini Spacecraft on its way to Saturn will also be presented.

Skywatch Line for Friday, July 30, through Sunday, August 1, 2004 by Alan French

The Moon will be Full this weekend, so the night sky will be dominated by bright moonlight.  Full Moon occurs when the Moon is on the side of the Earth directly opposite the Sun, which will be at 2:05 PM on Saturday afternoon.  The Moon will be below our horizon then, but it will be a beautiful sight as it rises in the southeast at 8:51 Saturday evening.

You may recall that the last Full Moon was also in July – on July 2.  This makes the upcoming Full Moon a "Blue Moon," a term that has come to mean the relative rare second Full Moon in one month.  Originally, however, the term applied to an even rarer event – moons that actually looked blue.  Why would the Moon sometimes look blue?

Scientists have found that tiny particles in the Earth's atmosphere can act like a filter and make things look bluish.  This can be obvious at night when the Moon may be the only bright object visible.  The particles can be tiny water droplets, ice crystals, very fine sand, dust, or ash.  When the air is filled with clouds of such particles, and they are all the right size, the Moon may look very blue at any phase.

There have been times in the Earth's history when blue moons were actually common.  In 1883, the huge explosion of Krakatoa sent a huge amount of ash way up into the Earth's atmosphere.  For years, people saw blue moons, and sometimes green moons.  The sunsets were also extremely impressive.  Other volcanoes, including Mount St. Helens, produced blue moons, although for a much shorter time.  Fires can also cause the Moon to appear blue, although the extremely small particles produced by fires are most likely to cause a red moon.

I have never been fortunate enough to see a true Blue Moon, but I will keep looking at those clear nights when the Moon is in the sky.  Have you ever seen a blue Moon?

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