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     Abrams Planetarium SKYWATCHER'S DIARY August 1997
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The Skywatcher's Diary for August 1997 has been prepared by  Robert
C. Victor. 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 recent issue of Sky Calendar is available over the Internet. It
can be viewed via a World-Wide Web browser such as Netscape or
Internet Explorer, directly at URL:
http://www.pa.msu.edu/abrams/apr97skycal.html

If you would like a printed sample of the August issue, send a long,
self-addressed stamped envelope to:

August 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 Internet Explorer, 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

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August Planetary Highlights:

Evening Planets: Venus gleams very low in W to WSW at dusk. At
mag -4 it appears as brightest "star" in the night sky, but it sets before
nightfall (in northern U.S.) in August, and won't be seen in a fully dark
sky until next month. Watch Venus' setting place shift southward by
about 5 degrees per week; Venus sets due west just after midmonth,
and will set farthest S of west on Nov. 6. Mercury is visible to lower
right of Venus first week of August. On August 3 Mars and Spica are
just 1.6! apart in WSW, 40 degrees upper left of Venus. For rest of
month, watch the changing configuration of Venus, Mars, and Spica, as
Mars moves to upper left of Spica, and Venus approaches Spica from
the lower right. On second weekend of August, bright Jupiter is at
opposition and is up all night; look low in ESE at dusk, highest in south
in the middle of the night, and low in WSW at dawn. Once Venus has
set, Jupiter at mag -2.8 is brightest "star" in sky until dawn.

Late evening until dawn: Saturn rises just N of E about 3 hours after
sunset Aug 1, to 1-3/4 hours after sunset on Aug 31, and is high in S to
SW at dawn. Saturn reaches its high point in south four hours later and
22 degrees higher than Jupiter does. Saturn's rings are now 11 degrees
from edge-on; they were edgewise and invisible just two years ago.

On Aug 5 at dusk a thin crescent Moon forms  a compact gathering
with Mercury and Venus which can be enjoyed with binoculars. As the
Moon waxes from crescent to full Aug 6-17 and moves eastward from
Venus, it guides skywatchers to two additional planets and two bright
stars: Mars and Spica Aug 8 and 9, Antares on Aug 12, and Jupiter on
Aug 17. On the late evening of Aug 21, a waning gibbous Moon rises
close on the heels of Saturn, then gradually pulls away from it until
dawn on Aug 22. In the predawn hours of Aug 25, the Moon passes
through the Hyades star cluster, occulting some stars and approaching
Aldebaran.

Perseid meteors, best observed in predawn darkness hours, increase in
number each successive morning, August 8-11, and reach peak on
Tuesday morning, August 12. For tips on how to observe meteors, visit
SKY Online's Meteor Page at:
http://www.skypub.com/meteors/meteors.shtml

Many sky-gazers and their families will be planning to spend a summer
vacation or weekend at a star party or gathering of amateur astronomers
at a dark viewing site. For Sky & Telescope magazine's list of star
parties and astronomy meetings, visit the Website:
http://www.skypub.com/calendar/calendar.shtml

*********SKYWATCHER'S DIARY: AUGUST 1997*********
Friday, August 1
About 45 minutes after sunset, find brilliant Venus very low in W.
Using binoculars as twilight deepens, look for Mercury 5 degrees to its
lower right. In the southwest, find Mars with Spica 2 degrees lower left;
watch them nightly! Bright Jupiter has just risen in ESE.

Saturday, August 2
New Moon Sunday, 4:14 a.m. EDT; first easy view for northern states
is Tuesday at dusk. Before the Moon gets bright, these are fine evenings
for viewing the Milky Way.

The Mir Russian Space Station may now be making evening passes
over North America. For predictions for various cities, visit the
SatPasses Website at: http://ssl.berkeley.edu/isi_www/satpasses.html

Sunday, August 3
Mars is 1.6 degrees upper right of Spica; they're closest tonight! Look
low SW at dusk, 40 degrees upper left of Venus.

Monday, August 4
Using binoculars 15 minutes after sunset, look very low 10 degrees
north of due west for the thin crescent young Moon. It is within 15
degrees lower right of Venus. After the Moon sets, try for Mercury 6
degrees to Venus' lower right. As the sky darkens, Mars is in WSW 1.7
degrees directly above Spica tonight, while bright Jupiter has risen in
ESE.

Tuesday, August 5
About 45 minutes after sunset, the crescent Moon is very low in W,
with Venus 4 degrees upper left, and Mercury 2 degrees lower right.
(From the West Coast, Moon is about 3 degrees from each.) Binoculars
may be needed to see Mercury, especially from northern states. In
WSW, Mars is 2 degrees upper left of Spica. Jupiter is very low in
ESE.

Wednesday, August 6
Forty-five minutes after sunset, the crescent Moon is very low, just S of
west. Brilliant Venus is within 8 degrees to its lower right, and
binoculars may be needed to see Mercury within 7 degrees lower right
of Venus. Some 30 degrees to Moon's upper left are Spica and Mars,
about 2.4 degrees apart.

Thursday, August 7
An hour after sunset, the crescent Moon is located nearly midway
between Venus and Mars. Tonight Spica is within 3 degrees to Mars'
lower right.

Friday, August 8
At dusk Spica and Mars are in WSW, 6  to 9 degrees left of the crescent
Moon. Mars is the higher object, farther from the Moon.

Saturday, August 9
Tonight at dusk, the five brightest objects, in order of brilliance, are: The
Moon in SW; Venus very low in W, 40 degrees to Moon's lower right;
Jupiter very low in ESE; Arcturus high in WSW, nearly 30 degrees to
Moon's upper right; and Vega just E of overhead. Tonight Jupiter is at
opposition, about 180 degrees away from the Sun and visible all night.
Farther down the list in brightness, but still of first magnitude, Mars and
Spica are 4 degrees apart, to Moon's lower right.

Sunday, August 10
This evening the Moon, nearly half full, shows spectacular surface
features easily observed with binoculars or a small telescope. Just after
nightfall, look 3  or 4 degrees to Moon's lower left for a 3rd-magnitude
star, Zubenelgenubi or Alpha in Libra. Binoculars show it has a 5th-
mag companion star just 4 arcminutes to its right.

Monday, August 11
Mars and Spica are still 5 degrees apart, close enough to fit within the
field of view of 7X binoculars, which enhance their contrasting colors.
Find them low in WSW at nightfall.

The Perseid meteors are near their peak in Tuesday's predawn hours --
from 5-1/2 hours before sunrise until first light of dawn. There's no
moonlight or twilight then, so a trip to a dark site would be worthwhile,
provided the sky is clear.

Tuesday, August 12
The Moon, two-thirds full, is in the south around sunset, and moves
into SSW as sky darkens. Note Antares, heart of Scorpius, 9 degrees
below the Moon.

For tips on how to observe meteors, visit SKY Online's Meteor Page at:
http://www.skypub.com/meteors/meteors.shtml

Wednesday, August 13
The Moon, in S at dusk, is three-quarters full. Note first-magnitude
reddish Antares 15 degrees to Moon's lower right.

Thursday, August 14
The Moon is in the south at nightfall, above the 8-star Teapot of
Sagittarius, the Archer. Even though these stars are moderately bright,
of 2nd and 3rd magnitude, they are subdued by bright moonlight, as are
the star clouds of the Milky Way. Wait at least a week; then the Moon
will rise after nightfall, and the Milky Way will shine in all its glory
provided your viewing site is dark enough.

Friday, August 15
As the sky darkens, locate the Big Dipper well up in NW. Follow its
curved handle to golden Arcturus well up in W and then to blue-white
Spica low in WSW. Remember, "Follow the arc to Arcturus and drive
a spike to Spica." Don't confuse Spica with Mars, now 7 degrees to its
upper left.

Saturday, August 16
An hour after sunset, the Moon is in SE. Jupiter is within 12 degrees to
its lower left. Two hours later, Saturn is visible low in E. One-and-a-
half hours before sunup on Sunday, the Moon is about to set in WSW,
with Jupiter 8 degrees upper left. Saturn is then high in S.

Sunday, August 17
An hour after sunset, Jupiter is the bright "star" in SE, near the Moon.
One-and-a-half hours before sunrise on Monday, the Full "Green Corn"
Moon is in WSW, with Jupiter below. Saturn, then high in S, is 64
degrees from Jupiter.

Monday, August 18
The Moon, just past full, rises 10-15 degrees south of due east within
about 10 minutes after sunset from Michigan and elsewhere in northern
contiguous U.S., within 20 minutes after sunset from south Florida to
southern California, and about 30 minutes after sunset from Hawaii.
Does the rising Moon seem unusually large this evening? It does
happen to be at perigee (closest point of its orbit) tonight, 222,463 miles
from Earth.

To calculate sunset and moonrise times for your own location for
tonight and coming nights, use this website of the U.S. Naval
Observatory:
http://tycho.usno.navy.mil/srss.html

Tuesday, August 19
From Boston to Seattle, including lower Michigan, the Moon rises 6
degrees south of due east just over 45 minutes after sunset tonight.
From south Florida to southern California, the Moon rises just over an
hour after sunset. Note the Moon's reddish color and vertically flattened
shape as soon as it has completely risen. Both are atmospheric effects.
But the Moon's large apparent width when rising or setting is neither
real nor atmospheric, but is an illusion of the mind. Even though the
Moon when seen overhead is nearly 4,000 miles closer to Earth than
when it was on the horizon earlier the same night, the Moon overhead
seems smaller. Measurements of photographs show that it is in fact
larger when overhead.

Wednesday, August 20
Here's another chance to observe the "Moon illusion", the seemingly
large size of the rising Moon. Tonight from Boston to Seattle, including
lower Michigan, the Moon rises due east within 1-1/2 hours after
sunset. From south Florida to southern California, you'll need to wait
nearly two hours after sunset until moonrise. An hour or so after the
Moon appears, look for Saturn 14 degrees to Moon's lower left.

Thursday, August 21
Tonight the Moon rises after nightfall, allowing a brief interval to enjoy
very dark skies and the summer Milky Way. From Boston to Seattle,
including lower Michigan, the waning gibbous Moon clears the horizon
just over 2 hours after sunset. From south Florida to southern
California, the waiting time after sunset is just over 2-1/2 hours. Half an
hour after the Moon rises, from Boston, Saturn can be seen just 1
degree upper right of the Moon's center. From south Florida to lower
Michigan, Saturn is 1.3 degrees from Moon's center. From Seattle the
Moon-Saturn distance is 2.6 degrees; from southern California, over 3
degrees. From all locations, by an hour before sunup on Friday
morning, Moon and Saturn will be high in SSW, about 3 degrees
farther apart.

Friday, August 22
Across the northern half of the U.S., the Moon rises north of east within
three hours after sundown. From south Florida and south Texas, the
waiting time is about 3-1/2 hours. Watch for the rising Moon about 16
degrees lower left of Saturn. An hour before sunup on Saturday, the
Moon will be high in S, with Saturn in SSW, 19 degrees to Moon's
lower right. A telescope shows Saturn rings, now tipped 11 degrees
from edge-on.

Saturday, August 23
Now that the Moon rises late, evenings from now until early September
are ideal for viewing the summer Milky Way. At nightfall look south,
between Jupiter and Antares, for the eight stars of 2nd and 3rd
magnitude forming the Teapot. From a very dark site, the Milky Way
looks like clouds of steam rising from the Teapot's spout. Poised just
above the spout is the Greater Sagittarius Star Cloud, forming part of
the Milky Way's spiral arm which is the next one inward from ours.
Just east of overhead at nightfall, along the main axis of the Northern
Cross, is the Cygnus Star Cloud, consisting of stars within our own
spiral arm, ahead of us and just within our orbit around the center of our
Galaxy. Since the stars of the Cygnus Star Cloud are relatively close by,
binoculars easily resolve it into many stars. Compare its appearance to
the more distant Greater Sagittarius Star Cloud.

If you have difficulty seeing the Milky Way from your observing site
and would like information on how to help solve the likely problem,
point your Web browser to:
Fred Schaaf's Light-Pollution Notes:
http://www.skypub.com/lpnotes/lpnotes.html
International Dark-Sky Association:     http://www.darksky.org/~ida

Sunday, August 24
The Moon, at Last Quarter phase and half full, rises in ENE within 4-
1/4 hours after sunset from northern U.S., and later for observers
farther south. From then until dawn on Monday, the Moon passes
through the Hyades cluster, occulting or covering some stars. The
leading bright edge of the Moon reaches first-magnitude Aldebaran, eye
of Taurus, just before sunrise in Hawaii, and in daylight around 10 a.m.
PDT from the West Coast. A telescope should be used to observe these
events.

Monday, August 25
An hour after sunset, brilliant Venus is very low, south of west. Mars is
27 degrees to Venus' upper left. Tonight Spica is midway between the
two planets. Venus will pass closely upper right of Spica on September
6. Look nightly.

Tuesday, August 26
An hour before sunup on Wednesday, locate reddish Betelgeuse,
shoulder of Orion, in ESE, 11 degrees to Moon's lower right. Blue-
white Rigel, Orion's foot, is 19 degrees lower right of Betelgeuse.
Between these two bright stars lies a short, nearly vertical line of three
stars: Orion's belt. Follow the belt downward to Sirius, the "Dog Star",
which faithfully follows the Hunter across the sky.

Wednesday, August 27
An hour before sunrise on Thursday, the waning crescent Moon is in E,
about a third of the way from horizon to overhead. Look 15 degrees to
its lower right for Procyon, the brightest star in the constellation Canis
Minor, the Little Dog. A similar distance to Moon's left are Pollux and
Castor, the heads of Gemini, the Twins. Some 19 degrees to Moon's
upper right is Betelgeuse, shoulder of Orion. Betelgeuse, Procyon, and
Sirius (the brightest star) form the nearly equilateral Winter Triangle.

Thursday, August 28
An hour after sunset, brilliant Venus is very low, about 10 degrees
south of west. Look for the star Spica 10 degrees to Venus' upper left
and 15 degrees to Mars' lower right. Bright Jupiter is in SE.

An hour before sunup on Friday, the crescent Moon is in the east, with
Procyon, the "Little Dog Star," within 12 degrees lower right. Pollux,
the brighter of the Gemini twins, is 12 degrees to Moon's upper left;
Castor the other twin, is 4-1/2 degrees upper left of Pollux.

Friday, August 29
On Saturday an hour before sunrise, the thin crescent Moon is low, just
north  of due east. Note earthshine on the Moon's dark side, and Pollux
about 19 degrees above the Moon. Procyon is nearly as far to Moon's
upper right. Saturn is high in SW.

Saturday, August 30
Last chance to view the old crescent Moon: An hour before sunup on
Sunday, the very slender Moon can be found just above the horizon, 10
to 15 degrees north of due east. From mid-Michigan, the Moon is 38
hours before New. Can you track it until sunrise?

Sunday, August 31
Locate brilliant Venus in WSW at dusk. Within an hour after sunset,
Spica and Mars should be visible 7 degrees and 24 degrees to its upper
left.

Monday, September 1
New Moon occurs today, 7:52 p.m. EDT. In evening sky in next two
weeks, Moon passes three bright planets and two bright stars. Look
nightly at dusk, starting Wednesday.

********* end of Skywatcher's Diary for August 1997 *********