Abrams Planetarium Skywatcher's Diary
February 1998
(Full Graphics Version)
To the reader
The Skywatcher's Diary for February 1998 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 at
http://www.pa.msu.edu/abrams/apr97skycal.html
If you would like a printed sample of the February issue, 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 with a World-Wide Web browser at
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/
At dusk at start of February, three planets are visible. Saturn
(mag. +0.7) is well up in SW, near crescent Moon on Feb. 1 as depicted
on Sky Calendar. Faint Mars (mag. +1.2) and bright Jupiter
(mag. -2.0) are very low in WSW, far to Saturn's lower right. Mars and
Jupiter are still within 7 degrees apart on Feb. 1, and can be seen
together within field of 7-power binoculars. Around end of first week (see
Feb. 7) Jupiter sinks into twilight. Mars and Saturn follow Jupiter
into the twilight glow, but not until March. Meanwhile, watch the Mars-Saturn
gap narrow from nearly 40 degrees on Feb. 1, to 20 degrees on Mar. 1. A
young crescent Moon forms pretty groupings with them Feb. 27-Mar.
1. Saturn's rings are tipped 10 degrees from edgewise on Feb. 7,
11 degrees on Mar. 1. Morning: Venus, at mag. -4.6, its brightest
this year, now rises in ESE before first light of dawn. Six boxes on Sky
Calendar depict Venus an hour before sunrise. To see Venus in daylight,
just follow it until sunrise and beyond. The old Moon provides help
Feb. 23. Daytime is best for using binoculars or telescope to see Venus'
crescent phase. Venus is upper right of rising Sun, by 25 degrees on Feb.
1, 43 degrees on Feb. 28. Crescent Venus on Feb. 1 is 9% lighted and 0.9'
(arcminute) across; on Feb. 28 it's 32% lit and 0.6' across.
A solar eclipse on Feb. 26, total in a track across the Caribbean,
is partial as far north as southernmost CA, lower MI, and Labrador, where
the Moon covers at most a few percent of the Sun's disk. From Baton Rouge,
Atlanta, Greenville SC, and Richmond VA, Moon covers 25% of Sun's diameter
at deepest eclipse, and in Miami FL, 50% of solar diameter. For more on
the eclipse, see February Sky and Telescope magazine and visit the
websites: http://planets.gsfc.nasa.gov/eclipse/eclipse.html
and http://www.skypub.com/eclipses/eclipses.shtml
Skywatcher's Diary: February 1998
Sunday, February 1
Forty-five minutes after sunset, the two brightest objects in the sky are
the crescent Moon well up in SW, and Jupiter very low in WSW some 47 degrees
to Moon's lower right. As the sky darkens further, look for Mars within
7 degrees to Jupiter's upper left, and Saturn a degree or two to Moon's
right. A telescope shows spectacular detail on the Moon these nights, as
well as the rings of Saturn, tipped nearly 10 degrees from edge-on. Tonight
the Sun rises on the crater Theophilus. Through binoculars this feature
stands out along the terminator (day-night boundary), about 2/5 of the
way from the south cusp (point of the crescent) toward the north. Theophilus
is about 65 miles across and over 4 miles deep, with a large multiple central
"mountain" easily seen in binoculars. Beginning at sunset, carefully watch
Theophilus for 5 hours, and hour by hour you'll notice sunlight illuminating
progressively more of the crater's floor and its central mountain. Look
again on Monday evening. For a day-by-day description of lunar surface
features through the course of a lunar month, see the book, "Exploring
the Moon Through Binoculars and Small Telescope" by Ernest H. Cherrington,
Jr.
Monday, February 2
Tonight a pair of prominent lunar craters, Aristoteles and Eudoxus, lie
near the terminator (day-night boundary) less than one-fourth of the way
from the northern cusp (upper point of the crescent) toward the southern.
Can you see them in binoculars? An hour after sunset, Saturn is high in
SW some 15 degrees to the Moon's lower right. Jupiter is about to set in
WSW, 46 degrees lower right of Saturn. Faint Mars is 7 degrees to Jupiter's
upper left.
Tuesday, February 3
The Moon is at First Quarter phase high in SSE at sunset, 90 degrees or
one-quarter circle east of the setting Sun. Note the Moon is half full,
an ideal phase for seeing lunar surface features through binoculars and
telescopes. Using binoculars, "star-hop" to the long period variable star
Mira: From the Moon, go 7 or 8 degrees lower left to 2.7-mag. Alpha Ceti.
Then from Alpha, go 5 degrees lower right to 3.6-mag. Gamma, and then 3
degrees below Gamma to 4.1-mag. Delta Ceti. Finally, go 6 degrees lower
right of Delta to Mira. Is Mira still as bright as Delta? At its peak in
Feb. 1997, Mira matched Alpha in brightness.
Wednesday, February 4
At nightfall, locate the Pleiades star cluster high in south, about 10
degrees above Moon, and the bright star Aldebaran, eye of Taurus, a similar
distance to the Moon's east (left). By Thursday evening, the Moon will
have leapfrogged a few degrees past Aldebaran.
Four weeks from tonight, the Moon will have completed slightly more
than one orbit around the Earth and will occult or cover the star for observers
in most of eastern half of U.S. The International Occultation Timing Association
(IOTA) would like to receive videos of the March 4 occultation of Aldebaran,
taken by camcorders to obtain precise timings. For more information, see
our March Sky Calendar, the March issue of Sky & Telescope,
and the IOTA website at: http://www.sky.net/~robinson/iotandx.htm
Thursday, February 5
At intervals of about 584 days, (just over 19 months), Venus passes nearly
between Earth and Sun and switches from an "evening star" to a "morning
star". This last occurred in mid-January 1998 and will next happen in August
1999. For several weeks around those dates, Venus appears to retrograde
or move westward against the stars. Venus is just now ending retrograde.
On Friday morning look for Venus very low in ESE, and note Antares in SSE
40 degrees to Venus' upper right, and 2nd-mag. Sigma Sagittarii in handle
of the Teapot, 12 degrees to Venus' lower right. For several mornings these
distances will hold steady, then Venus will pull away from these stars
with increasing speed. By late March, Venus will be shifting eastward against
the stars by one degree per day.
Friday, February 6
An hour after sunset, locate the waxing gibbous Moon high in SE, with Betelgeuse,
shoulder of Orion, 11 degrees to its lower right. This weekend the Moon
joins Betelgeuse inside the huge Winter Hexagon, comprised, in clockwise
order, of the stars Aldebaran, Rigel, Sirius, Procyon, Pollux, Castor,
and Capella.
Milky Way Legacy opens tonight at Abrams Planetarium. Tour our
amazing home galaxy with noted author Ken Croswell and emerge with a clearer
view of our home in space. Find out some of the ways the Milky Way is very
special, and how, unlike most galaxies, it is equipped to create the variety
of ingredients needed for life. Showtimes: Fridays and Saturdays at 8 p.m.,
Sundays at 4 p.m., continuing through July.
Saturday, February 7
Forty-five minutes after sunset, bid farewell to Jupiter, for it's about
to set in WSW. Mars is still visible 10 degrees to Jupiter's upper left.
Binoculars help! If you're too late for Jupiter, then look for Mars 35
degrees to Saturn's lower right.
Sunday, February 8
WSKY ... Radio Station of the Stars, continues Sundays 2:30 p.m.
at Abrams Planetarium.
An hour after sunset, Moon is in the east with Procyon, the "Little
Dog" star 12 degrees lower right, and Pollux 11 degrees upper left. Castor
is 4-1/2 degrees upper left of Pollux. Sirius, the "Dog Star," the brightest
star in the night sky, is 26 degrees from Procyon and can also be found
by extending Orion's belt downward. Sirius, Procyon, and Betelgeuse (Orion's
shoulder) form the nearly equilateral Winter Triangle.
Monday, February 9
An hour after sunset, Moon is in east with Procyon 16 degrees to right
and Pollux a similar distance above. Regulus, heart of Leo, has just risen
25 degrees to Moon's lower left.
Tuesday, February 10
An hour after sunset, the Moon, approaching Full, is in east with Regulus
12 degrees lower left. Tonight's Full Moon is named the Snow or Hunger
Moon by Algonquin Indians. By an hour before sunrise on Wednesday, Moon
will be low in west, with Regulus within 8 degrees upper left.
Wednesday, February 11
An hour after sunset the rising Moon, just past Full, is closely accompanied
by Regulus within 2 degrees to its upper left. Binoculars help pick out
the star in the Moon's glare. As the night progresses, Moon and star gradually
separate. An hour before sunup on Thursday, Moon is in west with Regulus
about 5 degrees upper right.
Thursday, February 12
Two hours after sunset, the Moon is very low, just north of east, with
Regulus 13 degrees upper right (or above the Moon from south Florida).
Friday, February 13
At dark sites Feb. 13-27, the zodiacal light appears as a huge,
nearly vertical cone of dim light in W at nightfall. How far from the Sun
can you detect its glow? Mars, just above the WSW horizon, is 20 degrees
from the Sun, and Saturn is now 51 degrees from the Sun. From a fantastically
dark site, you may be able to trace the zodiacal light even past the Pleiades
or Seven Sisters star cluster, now 95 degrees from the Sun. For more on
this phenomenon, see http://antwrp.gsfc.nasa.gov/apod/ap970826.html
Saturday, February 14
At nightfall in mid-February, the Milky Way passes nearly overhead. Follow
its course from Cygnus low in NW, upward through Cepheus and Cassiopeia,
through Perseus and Auriga nearly overhead, then down past the horns of
Taurus and feet of Gemini and through the Winter Triangle in the SE. The
Milky Way of winter is more subtle and less bright than its summer counterpart,
because as we look up toward the horns of Taurus, we are facing away from
the bright center of our Galaxy. If you have trouble seeing the zodiacal
light or the Milky Way despite clear skies, your problem may be light
pollution. For information, see the webpage of the International Dark-Sky
Association at: http://www.darksky.org/~ida/index.html
Sunday, February 15
An hour after sunset, face WSW to find Mars 30 degrees lower right of Saturn.
They'll be 2 degrees apart by end of March, but will set in bright twilight.
About 5 hours after sunset, watch for the appearance of Spica in ESE, about
6 degrees to lower right of the waning gibbous Moon. Spica and Moon keep
close company for the rest of the night; an hour before sunrise on Monday
they're in SW, with Spica about 5 degrees below the Moon.
Monday, February 16
Within 5-1/2 hours after sunset, Moon rises 10 to 15 degrees south of east.
Note Spica about 10 degrees to Moon's upper right. You can also locate
Spica by following the curve of the Big Dipper's handle: "Follow the arc
to Arcturus and drive a spike to Spica." By an hour before sunup on Tuesday,
face SW to find Spica 12 degrees to Moon's lower right.
Tuesday, February 17
An hour after sunset, the bright "markers" in the zodiac constellations
(in the plane of the solar system), from western horizon, through high
in south, to the eastern horizon, are Mars, Saturn, Aldebaran in Taurus,
Pollux in Gemini, and Regulus in Leo. An hour before sunup on Wednesday,
the bright zodiac markers, from west to east, are Regulus, Spica in Virgo,
the Moon, Antares in Scorpius, and Venus.
Around this date each year, the star Regulus in Leo the Lion is at opposition
to the Sun as the Earth passes between it and the Sun. Look for Regulus
low in eastern sky at dusk, high in south in the middle of the night, and
low in W at dawn. During August, half a year from now, Earth will have
travelled halfway around the Sun, and Regulus will be lost in the solar
glare.
Wednesday, February 18
An hour before sunup on Thursday, the Moon is in S, with Antares, heart
of the Scorpion, 14 degrees lower left. Moon reaches Last Quarter phase
that morning, 90 degrees or one-quarter circle west of Sun. At sunrise,
note the Moon's left half is illuminated.
Thursday, February 19
An hour before sunrise on Friday, a fat crescent Moon is in SSE to S, with
Antares, heart of Scorpius, 9 degrees lower right. Venus, gleaming in SE,
is at greatest brilliancy and now shows a crescent, 25 percent full, through
binoculars and small telescopes. Just after sunrise, spot Venus in the
daytime 40 degrees from Sun and Moon, just above the midpoint between them.
Venus passes due south 2 hours 42 minutes earlier and 5 degrees lower than
Friday's midday Sun does. (Midday is halfway between sunrise and sunset.)
Friday, February 20
Modeling planet visibility: Mercury will appear on the far side
of the Sun on Sunday, and Jupiter will do so just a day later. Imagine
our solar system from above, and visualize four bodies currently arranged
in a straight line, in this order: Earth, Sun, Mercury, Jupiter. As weeks
pass, the planets orbit counterclockwise around the Sun at different rates,
the inner planets revolving faster. So as seen from Earth, speedy Mercury
will emerge to the left of the Sun, while leisurely Jupiter will emerge
to the right of the Sun. Meanwhile the Earth rotates counterclockwise on
its axis, causing day and night and the daily rising and setting of Sun,
Moon, planets, and stars. Recruit volunteers to represent the Sun and planets,
and use this solar system model to explain that after appearing behind
the Sun, an inner planet (Mercury in this case) will next be visible in
the evening sky after sunset, while an outer planet (Jupiter) will
next be seen in the morning sky before sunrise. During March, in
fact, Mercury will emerge as an evening "star" by the end of the first
week, and Jupiter will emerge as a morning "star" before month's end.
Saturday, February 21
An hour after sunset, locate Saturn nearly 30 degrees up in WSW, and look
for Mars nearly 26 degrees to its lower right. These are planets outside
the Earth's orbit and consequently they orbit the Sun more slowly than
Earth does. Both planets appear lower in the western sky each evening,
and will sink into bright twilight by the end of March. Saturn will be
in conjunction beyond the Sun on April 13, and Mars on May 12. Both planets
will emerge into the eastern morning sky, Saturn in May, and Mars in July.
An hour before sunrise on Sunday, the crescent Moon is in SE with brilliant
Venus within 16 degrees lower left. Follow them until well past sunrise.
Sunday, February 22
In predawn on Monday, a beautiful pairing of Moon and Venus -- the two
brightest nighttime objects -- rewards early risers. Circumstances vary
with location. From Lansing, Michigan, Venus rises 4 degrees to Moon's
left at 5:03 a.m. EST, just as Moon's crescent becomes fully visible, 2
hours 20 minutes before sunrise. From most locations in U.S. the views
of Moon and Venus should be especially striking from two hours to one hour
before sunrise. Venus is near greatest brilliancy and is nearly at its
highest in the sky for this morning apparition, so this will be one of
the most impressive of the monthly pairings of the Moon and Venus. (April
23 will be even more so, including Jupiter only about half a degree from
Venus.) Follow Monday's pairing well into daytime, even past midday! From
mid-Michigan, Moon-Venus appear closest, 2 degrees apart, just after 1:30
p.m. EST.
Monday, February 23
An hour before sunrise on Tuesday, the thin old crescent Moon is very low
in ESE, with brilliant Venus 11 degrees to upper right.
Tuesday, February 24
Thirty minutes before sunrise on Wednesday, binoculars give the best view
of the old crescent Moon, just risen in ESE, 25 degrees to lower left of
Venus. This is your last chance to see an illuminated crescent Moon until
early Friday evening!
Wednesday, February 25
Thursday's solar eclipse, total in a track across the Caribbean,
is partial as far north as southernmost CA, lower MI, and Labrador, where
the Moon covers at most a few percent of the Sun's disk. From Baton Rouge,
Atlanta, Greenville SC, and Richmond VA, Moon covers 25% of Sun's diameter
at deepest eclipse, and in Miami FL, 50% of solar diameter. From Michigan,
the Moon takes a very small "bite" out of the Sun, as follows:
| City |
Time of Deepest Eclipse |
Magnitude |
| Grand Rapids |
1:00 P.M. EST |
5% |
| East Lansing |
1:02 P.M. EST |
6% |
| Ann Arbor |
1:03 P.M. EST |
8% |
| Flint |
1:03 P.M. EST |
7% |
| Detroit |
1:04 P.M. EST |
9% |
The magnitude of the eclipse is the fraction of the Sun's diameter covered
at the peak of the eclipse. View the eclipse safely! DO NOT attempt
to view any stage of the eclipse with the naked eye. One safe method
of observing the eclipse is to make a small pencil-point hole in an index
card and, standing with your back to the Sun, allow sunlight to
shine through the hole to form a projected image on a second white card,
held 2-4 feet away. To improve image sharpness, use a smaller hole and
employ a long cardboard box to mount the pinhole card at one end and screen
(white paper) on the inside at the other end. In East Lansing, begin safe
viewing of the eclipse at 12:33 p.m. EST, as the Moon begins to take a
"bite" out of the Sun's disk. Deepest eclipse occurs there at 1:02 p.m.,
and the moon completely uncovers the Sun's disk at 1:30 p.m.
For more on the eclipse, including other safe methods of observing it
and times for various locations, see February issue of Sky and Telescope
magazine and visit the websites: http://planets.gsfc.nasa.gov/eclipse/eclipse.html
and http://www.skypub.com/eclipses/eclipses.shtml
Thursday, February 26
It's not too early to begin planning for the solar eclipse of August 11,
1999. The centerline of the path of totality of next year's event crosses
southwestern England, northern France, southern Germany, Austria, Hungary,
Romania, Bulgaria, the Black Sea, Turkey, Iraq, Iran, Pakistan, and India.
That will be the last total solar eclipse conveniently accessible to North
Americans until the year 2017, when the path of total eclipse will cross
the United States from Oregon to South Carolina.
Friday, February 27
About 45 minutes after sunset, look for the first young crescent Moon very
low, about 10 degrees south of due west. In Michigan, some 30 hours have
passed since Thursday's eclipse. Faint Mars is less than a degree to Moon's
right. Binoculars give a fine view of the thin crescent with Mars. Saturn
hovers 22 degrees to their upper left. Look nightly.
Saturday, February 28
Forty-five minutes to an hour after sunset, look between WSW and W for
the crescent Moon, with Saturn within 7 degrees above. Mars is about 14
degrees to Moon's lower right. By Sunday evening, Moon will climb to Saturn's
upper left.
