Abrams Planetarium
SKYWATCHER'S DIARY: August 1997
To the reader
The Skywatcher's Diary for August 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 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 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/
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.
For tips on how to observe meteors, visit SKY Online's Meteor Page at:
http://www.skypub.com/meteors/meteors.shtml
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.
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.
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