Abrams Planetarium
SKYWATCHER'S DIARY: October 1996
To the reader
The Skywatcher's Diary for October 1996 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 Sky Calendar from a previous month is available over the Internet.
It can be viewed via a World-Wide Web browser such at 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:
October 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/
Moon, Planets, and Comets Hale-Bopp and Tabur
in October
Morning Planets: Brilliant Venus rises 3 hours before sunrise; in E to
ESE at dawn. Faint Mars is 14 to 32 degrees upper right of Venus. Both
planets have very pretty conjunctions with Regulus this month,
described in Skywatcher's Diary and illustrated on our Sky Calendar.
Mercury Oct 1-19 is very low in E, 23 to 29 deg lower left of Venus.
Saturn sets in W in twilight first two weeks, in predawn darkness rest
of October.
A waning crescent Moon forms pretty groupings with planets in eastern
morning sky Oct. 7-11. In Skywatcher's Diary, keep in mind that
morning events are described on the previous date.
Evening planets: Bright Jupiter is in S to SSW at dusk; the Moon is
nearby on Oct. 17 and 18. Saturn is in E to ESE at dusk, higher as
month progresses; the Moon passes nearby on the night of Oct. 23.
The Moon passes very close to Aldebaran on night of October 28-29.
Comet Hale-Bopp may outshine zero magnitude in March and April
1997. By the end of this month, if the comet behaves well, it may
brighten to 4th magnitude. Until it sinks from view in late December,
best time to see the comet remains around end of twilight, about 1-1/2
hours after sunset. In early October, use our all-sky map, September
Evening Skies, at URL: http://www.pa.msu.edu/abrams/skycal.html
To find the comet, begin with Summer Triangle: Vega and Deneb
overhead, and Altair high in south. Next, locate the 2.1-mag star
Rasalhague, or Alpha in Ophiuchus, high in SW to WSW. Marking the
head of Ophiuchus the Serpent-bearer, Alpha Oph stands out as it
completes a nearly equilateral triangle with Vega and Altair, 30 to 34 deg
on a side. Also find Alpha Oph two-fifths of the way from Altair to
Arcturus, and a little south of their connecting line. Once you're sure of
Alpha, find 2.8-mag Beta Oph 8 deg to its lower left. In October, Comet
Hale-Bopp is 10 deg to 8 deg lower left of Beta Oph and within same
binocular field as 4.5-mag 47 Oph (SAO141665), provided your
magnification doesn't exceed 11x. (You can find this faint star 11 deg
steeply lower left of Beta, halfway toward 2.8-mag Eta, as plotted on
the September map.) Best chances to view the comet with unaided eye:
Nightfall on Sept 29-Oct 18 and Oct 28-Nov 17, when Moon is either
not up, or if it's up, no more than half full. On Oct 1, Comet H-B is 10
deg lower left of Beta Oph and 0.8 deg upper left of 47 Oph. By Oct 18,
these values change to 9 deg and 2 deg, respectively; see also drawing
for Oct 14-19 on our Sky Calendar. During Oct 28-Nov 1, H-B is 8 deg
lower left of Beta Oph and 3 or 4 deg upper left of 47 Oph. In mid-
November, a line from Alpha to Beta Oph, 8 deg long, extended 7 deg,
ends at comet.
Comet Tabur, discovered August 19, glows between 6th and 5th
magnitude during October. As the Moon wanes during the first week,
Comet Tabur becomes an easy predawn object for binoculars provided
skies are dark. On the morning of October 2, Comet Tabur is 6 degrees
due north (upper left) of Castor. From one morning to the next through
Oct. 12, surrounding Tabur's sweep within 39 million miles of Earth on
Oct. 6, the comet shifts 4 degrees daily against the stars. In predawn on
Oct. 12, the comet passes within one degree S of Merak in the front of
the bowl of the Big Dipper (Beta in Ursa Major, the "Pointer Star" more
distant from the North Star). During Oct. 12 through 21, Comet Tabur
passes through the bowl and near the handle, ending within a degree of
the handle's end star, Eta in Ursa Major, on Oct. 21. By that date, the
comet's motion has slowed to 2 degrees per day. Four additional
mornings remain dark and moonless, with the comet moving 5 degrees
lower left of Eta UMa by Oct. 24. Bright moonlight interferes Oct. 25-
27, then the best viewing shifts to evening, about 1-1/2 hours after
sunset. On Oct. 28, the comet is in the NW as darkness falls, 12 deg left
of Eta Uma (end of Big Dipper's handle) and within 4 deg lower right
of 3.5-mag Beta in Bootes, the star at the top of that kite-shaped
constellation. By nightfall on Oct. 31, Comet Tabur passes within a
degree below Beta Boo and is 16 deg from Eta Uma. By Nov. 3, the
comet's motion slows to 1 degree per day.
For more on Comets Hale-Bopp and Tabur, try these Websites:
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
-
- Four hours after sunset, the Moon is low in ENE, with Aldebaran, eye
of Taurus, about 3 degrees upper right. By an hour before sunup on
Wednesday, the Moon is high in SSW with Aldebaran 6 degrees lower
right. Look also for brilliant Venus in E, with Mars 14 degrees upper
right, the star Regulus 1-3/4 degrees to Venus' lower left, and Mercury
near the horizon 24 degrees to Venus' lower left. Venus and Regulus
will be especially interesting to watch on Thursday and Friday
mornings.
-
- An hour before sunup on Thursday, the Moon is high in S with
Betelgeuse, Orion's shoulder, 10 degrees below. Venus gleams in the
east, closely accompanied by the star Regulus, heart of Leo, just 0.6
degree to its lower left. Watch the changing arrangement of Venus and
Regulus daily for the next several mornings.
-
- An hour before sunup on Friday, the Last Quarter Moon, actually half
full, is high in SSE. Brilliant Venus is in east with the star Regulus 0.6
degree above. Mars is 15 degrees upper right of the pair, and Mercury
near the horizon 23 degrees lower left of Venus. With Saturn about to
set in the west, a total of four planets are visiblle simultaneously!
-
- An hour before sunup on Saturday, the fat crescent Moon is high in SE.
Procyon, the Little Dog Star, is 11 degrees to Moon's lower right,
Pollux and Castor, the Gemini Twins, 12 to 16 degrees to Moon's
upper left, and Mars 24 degrees to Moon's lower left. The morning
"star" Venus is in E, with the star Regulus 1-3/4 degrees to its upper
right. Mercury, due east, is 23 degrees to Venus' lower left.
From Stardust to Life: A Cosmic Journey begins 8:00 p.m. tonight at
Abrams Planetarium.
-
- One and a half hours before sunup on Sunday, the crescent Moon is
one-third full in ESE and so does not interfere with viewing of Comet
Tabur. This recently discovered comet sweeps within 39 million miles
of Earth Sunday. Look for a pair of stars between 3rd and 4th
magnitude, 1.2 degrees apart, about midway between the Gemini Twins
and the Pointers of the Big Dipper. These are Iota and Kappa in Ursa
Major, marking the front feet of the Great Bear. The comet is visible in
binoculars as a 5th-magnitude fuzzy spot, 4 degrees above Iota and
Kappa on Sunday, and within two or three degrees to their upper left on
Monday. Procyon is 14 degrees to Moon's upper right, Mars 13
degrees and brilliant Venus 28 degrees to Moon's lower left. Regulus is
now nearly 3 degrees to upper right of Venus. By an hour before
sunup, Mercury appears 24 degrees to Venus' lower left.
-
- An hour before sunrise on Monday, the crescent Moon, one-quarter
illuminated in ESE, has Mars within 6 degrees upper left. Bright Venus
is 17 degrees to their lower left. Regulus is now 4 degrees upper right
of Venus, while Mercury remains very low in E, 24 degrees to Venus'
lower left.
-
- An hour before sunup on Tuesday, the crescent Moon, one-sixth sunlit,
is 30 degrees up in ESE. Venus gleams just 7 degrees to its lower left.
Regulus is 4 degrees to Venus' left and 5 degrees upper right of Venus.
Mars is about 13 degrees above the Moon. Mercury is still very low in
E, 24 degrees lower left of Venus.
-
- An hour before sunup on Wednesday, the thin bright crescent Moon is
in E to ESE, with earthshine illuminating the remainder of the disk.
Brilliant Venus is about 6 degrees above, and Mercury 20 degrees to
Moon's lower left. Note Regulus 6 degrees to Venus' upper right, and
Mars another 12 degrees beyond Regulus. Mars and Regulus will have
a close encounter in three weeks!
-
- An hour before sunup on Thursday, the thin crescent Moon is low, a
little south of due east, with Mercury about 9 degrees to its lower left.
Brilliant Venus is 16 degrees to Moon's upper right, Regulus 8 degrees
upper right of Venus, and Mars in turn 11 degrees upper right of
Regulus.
-
- Just before dawn's first light Oct 11-24, Comet Tabur is an easy target
for binoculars as it passes near stars in the Big Dipper standing on its
handle in NE. On Friday, the comet stands 4 degrees above Merak (Beta
in Ursa Major), one of the "Pointer Stars" in the front of the Big
Dipper's bowl, the pointer more distant from Polaris. On Saturday
Comet Tabur will pass less than a degree south of Merak. Venus shines
in E to ESE. As the sky brightens, look for four objects in a nearly
straight line sloping upward from the horizon. Regulus and Mars are
respectively 9 degrees and 19 degrees to Venus' upper right. One hour
before sunup on Friday, Mercury is only about 3 degrees above the
eastern horizon and 25 degrees to Venus' lower left. The very old Moon
is then just rising. In the next 15 minutes, the hairline-thin crescent
should be visible in binoculars 3 or 4 degrees to lower right of Mercury.
-
- An hour before sunrise on Saturday, locate brilliant Venus in E to ESE.
Note Regulus and Mars respectively 10 degrees and 20 degrees to
Venus' upper right. Can you detect any difference in the colors of Mars
and Regulus? It'll be easier to compare their colors for a few mornings
around Oct. 29, when they'll pass just over a degree apart.
-
- The Moon is New today at 10:14 a.m. EDT and is invisible. If you look
about 1-1/2 hours before sunup, the Moon will be absent from the
morning sky through Oct. 24. If your skies are very clear and dark, far
from the lights of "civilization", these are excellent mornings to try to
observe the zodiacal light. It appears as a huge softly luminous cone of
light sloping upward from the eastern horizon, seeming to engulf
Venus, Regulus, and Mars, and is caused by dust in the plane of the
solar system, the dust being originally from comets and asteroids. To
detect the zodiacal light about 1-1/2 hours before sunrise, compare that
section of the sky to the darker areas to its left and right. In the predawn
darkness of Sunday, use binoculars to scan along the bottom of the Big
Dipper's bowl in NE. You should find a fuzzy patch of about mag 5.5:
Comet Tabur nearly at its brightest.
-
- About 20 minutes after sunset, from a place with an unobstructed view,
look for the young crescent Moon very low in WSW. The Moon sets
early, easpecially from northern states, so don't be late!
Using binoculars one-and-a-half hours before sunup on Monday, look
inside the Big Dipper's bowl, 2 degrees from Gamma at the bottom
back corner, for Comet Tabur.
-
- About 45 minutes after sunset, the two brightest objects in the sky are
the crescent Moon very low in WSW, and Jupiter in S to SSW. As the
sky darkens slightly, can you find the star Antares, heart of the
Scorpion? Look for it about 30 degrees lower right of Jupiter and 20
degrees left of the Moon and a little higher. From northern states,
Antares disappears into the evening twilight glow each year in late
October. From southern states, Antares remains visible until early in
November.
Just before first light on Tuesday, binoculars will show Comet Tabur
just outside the back of the Big Dipper's bowl, 2 degrees from Delta
UMa, the star joining handle to bowl.
-
- Face SW within an hour after sunset to see Antares within 10 degrees
lower left of Moon. Jupiter is in SSW, 37 degrees to Moon's upper left.
Look nightly at the same hour; by Friday, the Moon will leapfrog past
Jupiter.
Face NE to see the Big Dipper standing on its handle one-and-a-half
hours before sunup. Beginning with the Pointer Star nearest to North
Star, the Big Dipper's stars are named in alphabetical order: Alpha and
Beta (the Pointers), Gamma, Delta (where handle joins bowl), Epsilon,
Zeta (at the bend of the handle) and Eta (at the end of the handle). From
now through Oct. 24 we'll use these stars to find Comet Tabur. On
Wednesday the comet is about 3 degrees below Delta, the star joining
handle to bowl. Use binoculars.
-
- At nightfall, about 1-1/2 hours after sunset, the crescent Moon is in SW,
with bright Jupiter in SSW 23 degrees to Moon's upper left. Using
binoculars, try this "star hop" from the Moon to Comet Hale-Bopp. The
field of view of 7-power binoculars is typically 7 degrees; of 10-power,
5 degrees. About 3 degrees to Moon's upper right is the 2.4-magnitude
star Eta in Ophiuchus, the Serpent-bearer. Nearly 4 degrees above Eta,
look for the 4.3-mag star Nu in Serpens, the Serpent. Extend the line
from Eta Oph to Nu Ser just over 6 deg upward past Nu, and there
you'll find the 4.6-mag star Mu in Ophiuchus. Look for a faint fuzzy
patch of light 4 deg upper right of Mu Oph. That's the comet! As a
check, the comet should be 1.8 deg upper left of a 4.5-mag star, 47
Ophiuchi or SAO141665.
In the northeast just before dawn's first light on Thursday, locate
Epsilon in Ursa Major, the first star in the handle of the Big Dipper
below Delta which joins handle to bowl. Binoculars show Comet Tabur
just over 2 degrees lower right of Epsilon. On Friday, the comet will be
3 degrees from both Epsilon and Zeta, the star at the bend of the handle.
-
- One-and-a-half hours after sunset, the two brightest evening objects are
10 degrees apart in SSW to SW: The Moon, with Jupiter to its left.
Another look at Comet Hale-Bopp, before the Moon gets too bright:
With unaided eye, locate the 2.4-magnitude star Eta Ophiuchi, about 14
deg to Moon's lower right. Then use binoculars to follow the path given
last night: 3.8 deg above Eta to 4.3-mag Nu Ser, then 6.3 deg above Nu
Ser to 4.6-mag Mu Oph, then 4.1 deg upper right of Mu to 4.5-mag 47
Oph and the comet, itself appearing as a hazy spot within 2 degrees
upper left of 47 Oph. If you have a star atlas, look for the star 47 Oph
midway between Alpha and Eta Oph, 11 deg from each.
-
- Tonight at dusk, the two brightest evening objects appear closest: The
fat crescent Moon, with Jupiter 6 or 7 degrees lower right. If skies are
clear, MSU Observatory will be open for public viewing tonight and
Saturday from 9 p.m. until 11 p.m., after the 8 p.m. showing of "From
Stardust to Life: A Cosmic Journey" at Abrams Planetarium. Telescopic
views will feature Moon and Saturn, with rings tipped less than 4
degrees from edge-on.
On Saturday 1-1/2 hours before sunup, Comet Tabur is 3 degrees lower
right of Mizar (Zeta in Ursa Major), the bright star at the bend of the
handle of the Big Dipper. Binoculars show the comet as a fuzzy spot,
and Mizar's companion Alcor just 0.2 degree to Mizar's lower left. By
Sunday morning, comet will be within 3 degrees above Eta, the end star
of the Big Dipper's handle.
-
- If you face the setting Sun this evening, you'll find the First Quarter
Moon in SSE, to your left, 90 degrees or one-quarter circle away from
the Sun. Note the Moon appears half full, with its right or west side (the
side facing the Sun) illuminated. Viewed through binoculars or a small
telescope within a few days of half full, the Moon reveals its surface
features in spectacular detail. MSU Observatory tonight: see Friday Oct.
18.
-
- High in ESE an hour before sunup, Mars and Regulus will appear no
more than 5 degrees apart beginning Monday and continuing through
Nov. 7. Look far to upper right of brilliant Venus. On Monday, Mars
will be nearly 5 degrees above Regulus. They're nearly matched in
brightness, but differ noticeably in color. On Oct. 29 they'll be just 1.2
degrees apart and it'll be easy to compare their colors.
On Monday 1-1/2 hours before sunrise, find the Big Dipper standing on
its handle in NE. Use binoculars to glimpse Comet Tabur less than a
degree to the upper left of Eta in Ursa Major, the trailing end star of the
Dipper's handle. On Tuesday morning, comet will be 1.5 degrees to
Eta's lower left; on Wednesday, nearly 3.5 degrees to Eta's lower left.
-
- In our final week of daylight saving time, you can still enjoy dark
morning skies without getting up inconveniently early. An hour before
sunrise note brilliant Venus in ESE with 2nd-magnitude Denebola, tail
of Leo, 11 degrees to its upper left. Far to their upper right, Mars is
closing in on Regulus, Leo's heart, for another week. Orion stands in
SW with his 3-star belt pointing to Sirius, the "Dog Star", in S to SSW.
-
- In late October and early November each year, the star Arcturus is
visible briefly both at dusk and at dawn. Tonight at dusk look for it low,
between W and WNW. On Wednesday at dawn, look very low in ENE.
When the sky is dark enough, you can use the handle of the Big Dipper
to "follow the arc to Arcturus." Right now Arcturus is more easily seen
in the early evening sky. But it's getting lower each evening and higher
each morning, and on the night of Oct. 28-29 it will be seen equally well
at dusk and dawn.
-
- In ESE an hour after sundown, Saturn glows only 5 degrees lower left
of the waxing gibbous Moon, while Jupiter shines brightly in SSW.
Last chance to see Comet Tabur in a moonless morning sky: One-and-a-
half hours before sunup Thursday, find the Big Dipper in NE, then use
binoculars to look 5 degrees lower left of Eta, the last star in the handle.
-
- This evening the Moon has "leapfrogged" past Saturn: An hour after
sunset, note the bright "star" 9 or 10 degrees to Moon's right. An hour
before sunup on Friday, high in ESE to SE and far upper right of
Venus, Mars stands within 3 degrees upper right of Regulus.
-
- From a vantage point with unobstructed views of the horizon toward E
and WSW, try to see the setting Sun and rising nearly full Moon
simultaneously. From East Lansing, MI at the optimal time, 6:31 p.m.
EDT or 9 minutes before sunset, the Sun is 18 degrees S of due west,
and the Moon 10 degrees N of due east. As the sky darkens, look for
Saturn 24 degrees to Moon's upper right.
-
- The Full Hunter's Moon happened earlier today, so the Moon won't be
up yet at sunset today. But you won't have long to wait! The Moon
rises this evening about 20-25 minutes after sunset. Remember to set
your clocks back one hour tonight. Sunrise will seem to come an hour
early on Sunday, and the Moon will still be up.
-
- The Moon rises in ESE about an hour after sunset tonight. Two or three
hours later look for the Pleiades (Seven Sisters) star cluster 10 degrees
to Moon's left. Binoculars will help you see this dim cluster in bright
moonlight. First-magnitude Aldebaran, eye of Taurus and follower of
the Pleiades, is about 15 deg to Moon's lower left. On Wednesday night
the Moon will appear very close to Aldebaran.
-
- For the first time since 1981, some observers within the U.S. -- in only
a small portion of northwest Washington state -- can experience an
occultation of Aldebaran by the Moon. From Vancouver BC, the star
will be covered by the Moon between 10:33 and 10:58 p.m. PST. From
Seattle, the Moon's southern edge will narrowly miss the star at 10:45
p.m. PST. As seen from mid-Michigan early Tuesday around 2:30 a.m.
EST, the Moon's southern edge will pass less than 0.2 degree north of
the star. The farther south you are, the wider will be the least separation
between Moon and Aldebaran. Binoculars may be required to detect the
star in the Moon's bright glare.
For the rest of the night, the Moon gradually widens its distance from
the star. By an hour before sunup on Tuesday, they're high in WSW to
W, while the Mars-Regulus pairing is at its closest, within 1.2 degrees
apart, high in SE.
-
- Within an hour after sunset, observe the bright star Arcturus low in
WNW. If you observe it daily at the same time (relative to the time of
sunset), you'll notice it's getting lower each evening. On what date will
you last see Arcturus in the evening?
-
- An hour after sunset these evenings, the five brightest objects visible, in
order of brightness, are Jupiter in SSW, Arcturus very low in WNW,
Vega very high in W, Capella very low in NNE to NE, and Saturn in
ESE.
An hour before sunrise on Thursday, the five brightest objects, in order
of brightness, are the Moon high in SW, Venus in ESE, Sirius in SSW,
Arcturus very low in ENE, and Capella high in WNW. Note
Betelgeuse, Orion's shoulder, 13 deg below the Moon.
-
- Right at nightfall, locate Big Dipper low in NW, with its handle pointing
left. The end (leftmost) star of the handle is Eta in Ursa Major; some 16
degrees to its left and a few degrees higher is 3.5-mag Beta in Bootes,
marking the top of that kite-shaped constellation. (Arcturus, visible
earlier in the evening, marks the bottom.) This evening Comet Tabur,
now faded to 6th magnitude, is just within the top of the kite, within a
degree below Beta. Next Sunday, this comet will reach perihelion, 78
million miles from the Sun.
An hour before sunup on Friday, the waning gibbous Moon, two-thirds
full, is high in SSW. Note the Little Dog Star, Procyon, 12 degrees to
Moon's lower left, and the Gemini Twins, Pollux and Castor, 4-1/2
degrees apart and 13 to 16 deg above the Moon.
-
- One hour before sunrise on Saturday, Moon is high in southern sky,
with Procyon, in Canis Minor, the Little Dog, 12 degrees lower right.
Pollux and Castor, the heads of the Twins, are 14 deg and 19 deg to
Moon's upper right.
-
- An hour before sunrise on Sunday, the Last Quarter Moon is high in
SSE to S, midway between Procyon in SSW and Mars in SE, and 20
degrees from each. Regulus, heart of Leo, is within 3 deg to Mars'
right. At sunrise the Moon is well up in SSW, 90 deg or one-quarter
circle from the Sun. Note the Moon's left or east half is illuminated by
the Sun.
-
- An hour before sunup on Monday, Regulus is about 6 degrees left of
the fat crescent Moon. Mars is just over 3 degrees to Regulus' lower
left.
-
- On Tuesday an hour before sunrise, the crescent Moon is in SE with
Mars 6 degrees above. Regulus is within 4 degrees upper right of Mars.
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