Abrams Planetarium
SKYWATCHER'S DIARY: May 1997
To the reader
The Skywatcher's Diary for May 1997 has been prepared by Robert C.
Victor. Sometimes you can see next month's in advance
by looking in our archives. Credit to
Abrams Planetarium,
Department of Physics and Astronomy at
Michigan State University, together with mention of our Sky Calendar, would be appreciated.
A sample issue of Sky Calendar from a previous month 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/apr97skycal.html
If you would like a printed sample of the May issue, send a long, self-
addressed stamped envelope to:
May 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
ftp://www.pa.msu.edu/pub/swd/
Comet Hale-Bopp departs evening sky: The earlier in May you look, the
better. For details, see our Skywatcher's Diary below, and our favorite
Hale-Bopp Websites:
http://encke.jpl.nasa.gov/
http://newproducts.jpl.nasa.gov/comet/
http://medicine.wustl.edu/~kronkg/1995_O1.html
http://cfa-www.harvard.edu/cfa/ps/pressreleases/HaleBopp.html
http://www.skypub.com/comets/comets.shtml
Our own H-B visibility site: http://www.pa.msu.edu/abrams/hbeve.html
Obtain Comet Hale-Bopp positions at nightfall for your own location,
calculated by the US Naval Observatory. But keep in mind the comet
sets early in evening and is best seen in twilight, before it gets too low.
For USNO local comet positions:
http://aa.usno.navy.mil/AA/data/docs/HaleBoppProg.html
To enhance your enjoyment of Comet Hale-Bopp, we 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
May Planetary Highlights:
Early in month, Venus is visible to sharp-eyed observers very low in
WNW about 20 minutes after sunset; see May 1, 7, 8, 17, below. Late
in month, Venus sets a full hour after Sun and is easier to spot. Mars is
high in SSE to SSW at dusk, and fades from magnitude -0.4 to +0.2.
Compare to Arcturus. Morning: For the first time since the early 1980's,
Jupiter and Saturn are within 60 degrees of each other. The entries for
April 29-May 3 and May 26-31 describe Moon passing through their
region of the sky. In early May Jupiter is in SE at dawn, and Saturn is
in E, just emerging from Sun's glare. By later in May both planets have
moved to upper right, because of Earth's revolution around the Sun.
Jupiter rounds the zodiac in 12 years (30 degrees per year), and Saturn
in about 30 years (12 degrees per year). The difference in their motions,
18 degrees per year, means that Jupiter passes Saturn about every 20
years. The next occasion will be in spring of the year 2000. They're
now 55 degrees apart. We hope you enjoy following their approach
during the next three years.
Planets at dusk: Venus setting in WNW; Mars in SSE to SSW.
Planets at dawn: Jupiter in SE to SSE; Saturn low in E.
-
- On April 2, Venus passed superior conjunction and was hidden on far
side of Sun. Venus will be an evening "star" until early in January
1998. Have you seen it yet in this apparition? Note where the Sun sets
along your horizon (you'll need an unobstructed view), then about 10-
15 minutes later, use binoculars to scan the horizon to upper left of
where Sun disappeared. This evening Venus is still within 8 degrees of
Sun. Venus gets easier to see in weeks and months ahead, as it moves
toward greatest elongation 47 degrees from Sun in early November, and
greatest brilliancy at magnitude -4.7 in early December.
-
- At nightfall Comet Hale-Bopp is low in WNW, 22 degrees lower left of
the bright star Capella. For several evenings, comet passes from right to
left, staying about 9 degrees below 2nd mag. star Elnath, northern horn
of Taurus, the Bull. Comet viewing, if sky is clear, in front of Abrams
Planetarium after 8 p.m. show, Comet: From Ice to Fire.
An hour before sunrise on Saturday, the old crescent Moon is very low
in E to ESE, 37 degrees to lower left of Jupiter. Another 10-15 minutes
later, use binoculars to try for Saturn, rising just north of east and 17
degrees to Moon's lower left. For another week or so, it will be much
easier to see Saturn from southern states.
-
- See today's box on our May Sky Calendar for a drawing of Comet
Hale-Bopp very low in WNW at nightfall. Comet viewing in front of
Abrams Planetarium: See May 2.
An hour before sunup on Sunday, the thin crescent Moon is just rising,
about 3 degrees north of due east. You'll need an unobstructed horizon.
About 10-15 minutes later, use binoculars to try for Saturn just 2 to 3
degrees to Moon's lower left. It will be very difficult in bright twilight
from northern states, easier in darker skies from southern states.
-
- At nightfall, Comet Hale-Bopp is very low in WNW, 23 degrees lower
left of bright Capella and 9 degrees below Elnath, the 2nd-mag. star
which marks the N horn of Taurus, the Bull. Just 22 degrees to left of
the comet (or to the comet's upper left if you're in southern U.S.) is the
red supergiant star Betelgeuse, shoulder of Orion. Just 30 days from
now, on June 3, Comet H-B will pass within 2 degrees above
Betelgeuse, but before then comet and star will be setting in bright
twilight shortly after sunset and won't be seen from mid-northern
latitudes.
-
- An hour after sunset, the almost perfectly equilateral Winter Triangle is
visible in WSW to W. It is comprised of Sirius about to set in WSW,
Procyon 26 degrees above it, and Betelgeuse in west. Look nightly, to
determine the last date you can observe each star.
-
- Today, Comet Hale-Bopp crosses southward through the ecliptic plane
just 11.5 million miles outside Earth's orbit. If this event had happened
Jan. 2, there would have been a close encounter! But the comet arrives 4
months too late; Earth has moved on, and is 174 million miles from the
comet tonight. Rapid southward motion hastens the comet's departure
for viewers in mid-northern latitudes. Here are last dates the comet may
be seen 5° up in deep twilight, with Sun 15° down (~1-1/2 hours after
sunset for lat. 40 deg N):
Lat. 49 deg N: May 6 Lat. 40 deg N: May 11
Lat. 30 deg N: May 16 Lat. 20 deg N: May 20
If comet isn't too faint, careful observers can follow it for a week or so
after these dates.
The Moon is New today at 4:46 p.m. EDT.
-
- About 20 minutes after sunset, the thin crescent Moon is very low,
about 15 degrees N of due west, with Venus 7 degrees to its lower
right. Binoculars help. As Moon sets and the sky darkens, try for
Aldebaran 7 or 8 degrees to Moon's upper left, and Comet Hale-Bopp 8
degrees above Aldebaran. Even if you miss Venus, Moon, and
Aldebaran, you can still find the comet at nightfall, very low in WNW,
24 degrees lower left of bright Capella.
-
- Farewell soon to Comet Hale-Bopp! As sky darkens, here's a splendid
sight for binoculars: Low in WNW, the departing comet is just 4
degrees upper right of a crescent Moon. Will anyone photograph this
pairing? By coincidence, it occurs one year to the day after the Moon
occulted the comet on May 8, 1996. Look earlier, about 30 minutes after
sunset, if you want to glimpse Venus 18 degrees to Moon's lower right,
and about one hour after sunset if you want to catch Aldebaran 6
degrees to Moon's lower right. Comet viewing in front of Abrams
Planetarium tonight, 9:45-10:15 p.m. if sky is clear.
-
- At nightfall, Betelgeuse is very low in west, 10 degrees to Moon's
lower left. Comet Hale-Bopp is very low in WNW, about 12 degrees to
Moon's lower right and 25 degrees to lower left of the bright star
Capella in the northwest. MSU Observatory will be open for our final
weekend of comet viewing tonight and Saturday, 9:15-11:00 p.m., if
skies are clear, after the 8 p.m. showings of Comet: From Ice to Fire at
Abrams Planetarium.
-
- An hour after sunset, Moon is in W with the Gemini Twins, Pollux and
Castor, 17 degrees above the Moon, and Betelgeuse, shoulder of Orion,
17 degrees below. Procyon, the Little Dog Star, is 17 degrees to
Moon's left. Can you still glimpse Sirius, the Dog Star, about to set in
WSW? As sky darkens, look for Comet Hale-Bopp very low in WNW,
about 24 degrees to Moon's lower right. Binoculars give a better view
of the departing comet.
Comet viewing at MSU Observatory: See May 9.
-
- As sky darkens, Moon is well up in west, with Pollux 12 degrees upper
right, and Procyon nearly as far to Moon's lower left. Castor is 4-1/2
degrees to right of Pollux. Locate bright Capella in NW. Comet Hale-
Bopp is very low in WNW, 26 degrees lower left of Capella.
-
- As nightfall approaches, Moon is well up in WSW, with the Gemini
twins, Pollux and Castor, 18-22 degrees to its right, and Procyon 16
degrees below the Moon.
Locate Capella in NW and Betelgeuse very low in W. Tonight Comet
Hale-Bopp is 27 degrees lower left of Capella and 15 degrees right of
Betelgeuse, or 15 degrees to Betelgeuse's lower right as seen from
southern U.S.
-
- When Moon is 90 degrees or 1/4 circle east of Sun, it reaches First
Quarter phase and appears half full in evening sky. At sunset tonight,
Moon is high in SW about 85 degrees from Sun, and appears slightly
less than half full. As sky darkens, note the star Regulus within 12
degrees to Moon's upper left, and bright reddish Mars within 19
degrees east (left) of Regulus. Watch Moon overtake Regulus and Mars
next three evenings.
-
- An hour after sunset, Moon is high in SW and just over half full. The
Moon has passed First Quarter phase. Just 3 or 4 degrees to Moon's
upper right is Regulus, heart of Leo the Lion. Mars is within 19 degrees
to their left. To find the departing Comet Hale-Bopp an hour after
sunset, locate bright Capella in NW and Betelgeuse very low in W. The
comet is very low in WNW, 28 degrees lower left of Capella and 14
degrees right of Betelgeuse. From northern U.S. the comet sets before
nightfall; binoculars help locate it in twilight.
-
- An hour after sunset, Moon is high in SSW, with bright Mars about 6
degrees to its upper left. The Moon is about two-thirds full tonight.
-
- An hour after sunset, Moon is high in S with Mars 6 degrees upper
right. Comet Hale-Bopp is then very low in WNW, 29 degrees lower
left of Capella, the bright star in NW.
-
- Half an hour after sunset, Venus is very low in WNW twilight. In
another half hour, Venus is gone, and the fat gibbous Moon is just east
of due south. Mars is to Moon's upper right and Spica to Moon's lower
left. Observe Regulus (in SW), Mars, Moon, and Spica (in SSE) are
arranged at roughly equal intervals along a nearly straight line.
-
- Moon is in SSE an hour after sunset, with Spica 5 or 6 degrees to its
lower left.
One last chance for Comet Hale-Bopp from northern states? An hour
after sunset, locate the bright star Capella in NW. About 17 degrees to
Capella's lower left is the 2nd-magnitude star Elnath, the northern horn
of Taurus, the Bull. A line from Capella to Elnath, extended in a straight
line 13 degrees lower left of Elnath, locates the comet very low in
WNW; use binoculars. Tonight the comet is 30 degrees lower left of
Capella and 11 degrees right of Betelgeuse, but the latter star has gotten
hard to see, low in twilight from northern states.
-
- Within an hour after sunset from S states, look for Comet H-B 14 deg
upper left of setting Venus and 10 deg right of Betelgeuse. An hour after
sunset, Moon is in SE to SSE with bright Arcturus nearly 30 degrees
upper left, and Spica about 9 deg to Moon's upper right. Locate these
bright stars by recalling, "Follow the arc (of Big Dipper's handle) to
Arcturus and drive a spike to Spica". Spica marks the spike or ear of
wheat in the hand of Virgo.
-
- An hour after sunset, Moon is in SE with Spica 22 degrees to its upper
right. In another hour Antares, heart of Scorpius, will apper in SE, 26
degrees to Moon's lower left. Still another hour later, look for the
Summer Triangle: Bright Vega well up in ENE, Deneb in NE 24
degrees to Vega's lower left, and Altair low in E, 34 degrees to Vega's
lower right.
-
- This is the last evening the Sun and Moon are visible simultaneously.
Look 20 minutes before sunset, when Moon will be very low in ESE
and Sun very low in WNW. Two hours after sunset look for Antares 14
degrees below Moon. By an hour before sunup on Thursday, the Full
"Corn Planting Moon" is low in SW with Antares 12 degrees to its
lower left. Thursday is the first morning Sun and Moon can be seen
simultaneously. Look 15 minutes after sunrise, when Moon is setting in
WSW and Sun has just risen in ENE.
-
- By this evening the Moon has passed Full. Half an hour after sunset,
watch for its rising in ESE. Two hours after sunset, look for Antares 9
degrees to Moon's lower right. An hour before sunup on Friday, look
SW to find Antares 10 degrees below the Moon.
-
- The three brightest stars visible an hour after sunset are: Arcturus high
in SE; Vega in ENE; and Capella in NW. Mars is well up in SSW; how
does it compare in brightness and color to these stars?
-
- Comet Hale-Bopp is now within 24 degrees of the Sun, and from
northern U.S. it sets less than an hour after sunset and is difficult to see.
The best places on Earth for viewing the comet tonight are near latitude
20 degrees south, where it's still visible with unaided eye at nightfall.
From southernmost U.S., using binoculars, try for Comet Hale-Bopp
very low in bright twilight, 13 degrees left of Venus and within 7
degrees right of Betelgeuse.
-
- The three brightest "stars" an hour before sunrise these mornings are:
Jupiter in SE to SSE; Arcturus in W; and Vega just west of overhead.
-
- The two brightest objects an hour before sunup on Tuesday are the
waning gibbous Moon in SSE with Jupiter 12 degrees to its lower left.
Note Saturn very low in east 55 degrees lower left of Jupiter. In spring
of the year 2000, the two planets will appear close to each other. Enjoy
follow them during the three years until then.
-
- An hour before sunrise on Wednesday, bright Jupiter is within 4
degrees to Moon's lower right. Face SE to SSE.
-
- An hour before sunup on Thursday, the Last Quarter Moon is in SE,
with Jupiter 17 degrees to its west (right). The Moon is 90 degrees or
one-quarter circle west of the Sun, and its left half is illuminated.
Binoculars show striking details along the Moon's terminator (day-night
boundary). Can you see the star Fomalhaut near horizon 22 degrees to
Moon's lower right?
-
- On Friday an hour before sunup, the fat crescent Moon is in ESE. Look
for bright Jupiter in SSE, 31 degrees to Moon's upper right, and Saturn
low in E, 24 degrees to Moon's lower left. Look daily, watching for the
Moon's changing position.
-
- An hour before sunup on Saturday, Moon is low, between E and ESE.
Saturn is 10 degrees to Moon's lower left.
-
- An hour before sunrise on Sunday, the waning crescent Moon is low in
east, with Saturn about 4 degrees to its upper right. Saturn's rings are
tipped nearly 11 degrees from edge-on. Two years ago, the rings were
presented edgewise to Earth and were invisible.
-
- Last easy chance to see the waning crescent Moon: On Monday, just
under an hour before sunup, look very low, just north of east. Saturn is
18 degrees to Moon's upper right. Watch the horizon 14 degrees lower
left of Moon for Mercury, just rising. Binoculars help locate this planet
in bright twilight.
-
- A final look at the old Moon: On Tuesday, about 40 minutes before
sunrise, look for a thin crescent Moon just above horizon, 15-20
degrees north of east. Binoculars help, and you'll need an unobstructed
view. Can you spot Mercury 2 to 3 degrees to Moon's upper left?
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