A sample back issue of Sky Calendar is available over the Internet. It can be viewed via a World-Wide Web browser such as Netscape or Mosaic, directly at URL:
http://www.pa.msu.edu/abrams/skycal.html
If you would like a printed sample, send a long, self-addressed stamped envelope to:
February Sky Calendar
Abrams Planetarium
Michigan State University
East Lansing, MI 48824
Each month, the Department of Physics and Astronomy at Michigan State University also makes Skywatcher's Diary available over the Internet. It can be accessed via a World-Wide Web browser such as Netscape or Mosaic, directly at URL:
http://www.pa.msu.edu/abrams/diary.html
The Skywatcher's Diary is also available via anonymous ftp at: www.pa.msu.edu in the directory /pub/swd
Comet Hale-Bopp in February
In the east 1-1/2 hours before sunrise in the first week of February, Comet Hale-Bopp passes through the lower right corner of the Summer Triangle 7 to 11 degrees upper left of Altair. The Moon begins the month as a fat crescent, getting thinner each morning and allowing darker skies for viewing Comet Hale-Bopp. By Feb. 5 the Moon will be just a thin crescent on ESE horizon as morning twilight begins. During Feb 6-19, there will be no Moon in sky at all during comet's predawn viewing time. Astronomers expect Comet Hale-Bopp to brighten and its tail to lengthen dramatically in February as the comet closes in on Earth and Sun.
Comet Hale-Bopp Resources
Abrams Planetarium H-B Visibilities Page: http://www.pa.msu.edu/abrams/hbvis.html
Comet Observation Home Page (JPL/NASA):
http://encke.jpl.nasa.gov/
Sky Online's Comet Page:
http://www.skypub.com/comets/comets.html
Press Info on H-B: http://cfa-www.harvard.edu/cfa/ps/HaleBopp.html
JPL Comet Hale-Bopp Home Page: http://newproducts.jpl.nasa.gov/comet/
Gary Kronk's H-B Page: http://medicine.wustl.edu/~kronkg/1995_O1.html
To enhance your enjoyment of Comet Hale-Bopp, we highly recommend these engaging and very readable books: "Comet of the Century: From Halley to Hale-Bopp", by Fred Schaaf, and "Everybody's Comet: A Layman's Guide to Comet Hale-Bopp", by Alan Hale.
For reviews of these and other books on Comet H-B, see February Sky & Telescope magazine or point your Web browser to:
http://www.skypub.com/comets/hb10.html
Want to observe the dust from old comets? If you're at a very clear, dark site in the middle of the night before the Moon rises, try for the Gegenschein (German for Counterglow), or faint oval patch of light reflected from comet and asteroid dust in the direction 180 degrees from the Sun. At this time of year, the Gegenschein is ideally placed in the faint constellation Cancer, the Crab, which contains no bright star, planets, or Milky Way whose brilliance would make the faint glow impossible to detect. Look for an oval cloud some 10 degrees long, inside the triangle formed by Pollux, Procyon, and Regulus. Use averted vision: Look to one side of the cloud to place its image on a more light-sensitive part of your retina than if you looked directly at it.
Go out again 45 minutes before sunrise. Can you see Mercury very low in ESE to SE, 24 degrees to Moon's lower left? Still another 15-20 minutes later -- now you're looking 25 to 30 minutes before sunrise -- try for Venus 8 degrees to Mercury's lower left, and even more difficult, Jupiter 1.6 degrees to Venus' lower left. Binoculars are recommended for watching the gatherings involving these three planets in bright twilight next 10 days. Skywatchers in southern states, where these planets rise earlier in a darker sky, will have an advantage.
http://www.pa.msu.edu/abrams/mars97retro.html
Forty-five minutes later, or 45 minutes before sunrise, Mercury should be visible 9 degrees to Moon's lower left. In another 15 minutes, watch for the rising of Venus 8 degrees to Mercury's lower left, and fainter Jupiter within 0.7 degree to left of Venus. Binoculars will help pick out the pair in bright twilight. You'll need a very clear sky and a horizon with an unobstructed view. Skywatchers in northern states, where these planets rise in brighter twilight nearer to the time of sunrise, will have a more difficult time seeing them.
About 45 minutes before sunup the old crescent Moon has risen in ESE with Mercury 7 degrees to its right. In another 15 minutes (about half an hour before sunrise), use binoculars to look 4 degrees below the delicate crescent for Venus and Jupiter only about 0.6 degree apart! Venus is the brighter member of the close pair, to Jupiter's lower left. You'll need very clear sky and an unobstructed view toward ESE to enjoy this planetary gathering. There are more planets here than meet the eye: Lost in bright twilight are Uranus 1.2 degrees lower left of Venus, and Neptune 2.4 degrees left of Mercury.
Using binoculars half an hour before sunup on Friday, use binoculars to try for a trio of planets in a line 8 degrees long, low in ESE to SE in bright twilight. Mercury is the highest, with Jupiter 6-1/2 degrees to its lower left. Venus is 1.5 degrees lower left of Jupiter. Not visible are Neptune 1.5 degrees upper left of Mercury, and Uranus 0.2 degree upper left of Venus. Too bad the gathering occurs in such bright twilight! Skywatchers in southern states will have an easier view.
The first naked-eye view of the young Moon for North Americans won't come until Saturday evening, ending the Islamic holy fasting month of Ramadan.
In the predawn darkness 90 minutes before sunrise on Saturday, look for the first-magnitude star Altair low in east, with Comet Hale-Bopp 11 degrees to its upper left. That morning Gamma Sagittae, a 3.5- magnitude orange star, appears within half a degree of the comet and should present a pretty sight for binoculars and small telescopes. Does the star appear to shine through the coma, or head of the comet?
In predawn darkness 90 minutes before sunup these mornings, locate the Summer Triangle in NE to E. Vega, its brightest and highest star, is high in ENE. Deneb is 24 degrees to Vega's lower left, and Altair 34 degrees to Vega's lower right. Altair to Deneb, the lowest side of the Triangle, is 38 degrees long. On Sunday morning, Comet Hale-Bopp is found along that side, nearly one-third of the way from Altair toward Deneb.
Tomorrow morning Comet Hale-Bopp is 167 million miles from Earth, 116 million miles from Sun.
Mira reported unusually bright January 31.
In the predawn darkness 1-1/2 hours before sunrise these mornings, locate the Summer Triangle in the eastern sky as described under February 8, above. Deneb, the lower left corner of the Triangle, marks the head of the Northern Cross, now lying on its side, with Deneb to your left. This first-magnitude star also marks the tail of Cygnus, the Swan, which for mid-northern latitudes these mornings is flying left to right parallel to the horizon across the northeastern sky. Day by day from now until early in March, Comet Hale-Bopp will be shifting slowly right to left below the stars of the Northern Cross. The comet is currently moving about one degree per day against background stars.
Half an hour before sunrise on Wednesday, Mercury will pass only 1 degree lower right of Jupiter, very low in ESE. The pair will be hard to see in bright twilight.
Morning skies remain dark and moonless, ideal for comet-watchers 1- 1/2 hours before sunup through next Wednesday, Feb. 19. Take advantage of clear mornings in this "window", because starting Thursday or Friday, Feb. 20 or 21, bright moonlight at that hour will seriously affect comet viewing. Look between E and ENE, below the Summer Triangle.
About 1-1/2 hours before sunrise these mornings, look between E and ENE more than halfway from horizon to overhead for the bright zero- magnitude bluish star Vega. Two first-magnitude stars, Deneb, 24 degrees to Vega's lower left, and Altair, 34 degrees to Vega's lower right, complete the Summer Triangle with Vega. On Monday Comet Hale-Bopp is 27 degrees below Vega (directly below as seen near latitude 43 degrees north, from Massachusetts through lower Michigan to Oregon) and 4 degrees below the midpoint of a line connecting Deneb and Altair. Moonlight will brighten the morning sky for the rest of this month, beginning Thursday or Friday. Look while you can!
On Wednesday about 1-1/2 hours before sunrise, skywatchers in northern states get their last chance to view Comet Hale-Bopp in a dark moonless sky until March, Look between E and ENE, 19 degrees lower right of first-magnitude Deneb and just 8 degrees lower right of the 2.5- mag star Epsilon Cygni, the end of the lower arm of the Northern Cross.
How many degrees long is the comet's tail you see? The answer depends in large part on the darkness of your skies. If the tail stretches as far as the 4th-mag star 41 Cygni, which is five degrees right of Epsilon Cygni, then it would be at least 4-1/2 deg long. If the end of the tail just brushes the axis of the Northern Cross, it would be just over 12 degrees long.
Keep good notes of your observations, including dates, times and sketches of what you see, to compare to your future observations of Comet Hale-Bopp. Bright moonlight will reduce the apparent tail length in coming days, but in March, once the Moon wanes to a thin crescent, the tail should appear even longer than it does now. On Wednesday the comet is 153 million miles from Earth, 108 million miles from Sun, with both distances closing!
In bright moonlit skies 1-1/2 hours before sunup on Saturday, locate the Northern Cross lying on its side in ENE. From left to right, the stars on its main axis are 1st mag Deneb, 2nd mag Gamma Cygni, 4th-mag Eta Cygni (faint), and 3rd-mag Albireo (Beta Cygni). From highest to lowest, the crossarm stars are Delta, Gamma, and Epsilon Cygni. On Saturday, a line from Deneb to Epsilon, 11 degrees long, extended half its length beyond Epsilon ends at the head of Comet Hale-Bopp.
In the coming week in the morning sky, Comet Hale-Bopp on Feb 23- 25 is 5 degrees lower right of Epsilon Cygni; on Feb 26 it is 5 degrees below Epsilon; on Feb 28 it is 7 deg lower left of Epsilon and 14 deg lower left of Deneb. Viewing improves daily as the Moon wanes; by March 2nd the Moon will wane to half full, and will brighten the sky only about ten percent as much as the Full Moon does.
The IDA can be reached by postal mail at 3545 N. Stewart Ave., Tucson, AZ 85716, USA. The IDA homepage on the World Wide Web is:
Another excellent website is Fred Schaaf's Light-Pollution Notes, at:
http://www.skypub.com/lpnotes/lpnotes.html
To find out the locations of the best and worst viewing sites in your part of the country, follow IDA's links to images and satellite imagery. Through these links you can call up an image of your own state at night showing the areas of light pollution. As an example, in lower Michigan, satellite photos reveal the darkest skies to be in the northeastern Lower Peninsula, not far from Alpena. Each year, a loosely-knit group of amateur astronomy enthusiasts that calls itself SMURFS (the Southern Michigan Unorganized Regional Federation of Stargazers) has a summer stargazing weekend there.
Here are some quotes from Fact Sheet on the International Dark-Sky Association:
"The human experience of the inspiring beauty of the cosmos is at risk for all people, not just scientists, as light pollution destroys our view of the beautiful dark sky.
"Quality lighting is the key to overcoming light pollution. It means better visibility at night, freedom from glare, and also a great deal of energy savings. Everyone wins".
Continuing with the night of Monday, February 24, once the Moon has risen just south of east within 2-1/2 hours after sunset, look for the red planet Mars about 4 degrees to its upper left. Tonight Mars is within 67 million miles of Earth, and by March 20 will be over 5 million miles closer. Moon and planet keep company the rest of the night, gradually spreading apart and ending in WSW at dawn on Tuesday.
One hour after sunset: Saturn low in WSW to W. Comet Hale-Bopp, only from northern U.S., about to set in NW, visible only if it's bright. Comet will greatly improve its position in evening sky for all of U.S. during March.
Horizon astronomy, about two hours after sunset: Can you track Saturn until just before it sets nearly due west, and catch Mars rising nearly due east before you lose sight of Saturn? To see both planets simultaneously just 2 degrees above opposite horizons, you'll need very clear skies and unobstructed views toward east and west. The best time to accomplish this task shifts 4 to 5 minutes earlier each day. By March 9, the task is quite a bit easier, as both planets will be seen simultaneously about 4 degrees up just one hour after sunset.
Three hours after sunset: Mars easy to see and very bright, in E to ESE.
One hour before sunrise: Waning gibbous Moon in SSW. Mars bright in WSW. Comet Hale-Bopp in ENE. Jupiter just rising in ESE.
On Sunday morning, Comet Hale-Bopp is in ENE 14 degrees lower right of Deneb. The comet is 136 million miles from Earth, 98 million miles from Sun. These distances will close to 122 million miles from Earth on March 22, and 85 million miles from Sun on March 31, respectively. March through May issues of the Abrams Planetarium Sky Calendar feature dayboxes and evening star charts to help you enjoy following the progress of the comet. A subscription may be ordered for $9.00 per year, from Abrams Planetarium, Michigan State University, East Lansing, MI 48824. The March and April issues are now available.
In late February 1996, for the first time since its last visit to the inner solar system 42 centuries ago, Comet Hale-Bopp crossed "above" or north of the Earth's orbital plane. In just 9 weeks, on May 6, Comet Hale-Bopp will cross back "below" or south of Earth's orbital plane, where it will remain until its next visit to the inner solar system 24 centuries from now.
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