This month's
most striking sights, involving the moon passing near planets and
bright stars, occur on the evenings of April 4, 6, 8-11, 14, and 30,
and the mornings of April 15, 18, 19, and 25-27. Morning events are
mentioned in Skywatcher's Guide one day prior to the event.
Saturday, April 1
-
An hour after sunset the thin crescent moon is very low in the W to
WNW. Second-magnitude Hamal, the brightest star in Aries the Ram,
shines 11 degrees to the moon's upper right. The glow you see on the
moon's dark side for the next few evenings is earthshine, or sunlight
reflected from Earth to illuminate the moon.
Daylight saving time begins 2 a.m. Sunday; remember to set your
clocks ahead one hour.
Sunday, April 2
- The thin crescent moon is in the W at dusk. Look at the same time
nightly, and you'll notice the moon is waxing, or getting thicker each
night as it moves higher and farther away from the Sun.
Monday, April 3
-
Face W as the sky darkens to find the 4-day-old crescent moon with
the Pleiades star cluster 7 degrees to its upper right. The reddish
first-magnitude star Aldebaran, the eye of Taurus the Bull, shines 13
degrees upper left of the moon.
Tuesday, April 4
-
An hour after sundown the waxing crescent moon is in the WSW to
W with reddish Aldebaran, the eye of the Bull, just 2 degrees to its
left. The moon is suspended just above the V-shaped Hyades
cluster, creating a beautiful field for binoculars, while the Seven
Sisters, or Pleiades, glitter 12 degrees to the moon's lower right.
Wednesday, April 5
-
At nightfall, the tips of the Bull's horns, 2nd-magnitude Beta Tauri
and 3rd-magnitude Zeta, are respectively 10 degrees upper right and
4 degrees above the moon. Ruddy 1st-magnitude Aldebaran shines
12 degrees to moon's lower right.
About 45 minutes before sunup brilliant Venus is very low in ESE.
Binoculars help locate Saturn 8 degrees lower left of Venus on
Thursday and about one degree closer each day.
Thursday, April 6
-
At dusk the moon, approaching First Quarter, is high in the SW to
WSW. First-magnitude Betelgeuse, 12 degrees to moon's lower left,
marks the bright shoulder of the striking pattern of Orion the Hunter.
Three stars in a row mark his belt, and Rigel marks his bright foot.
As the sky darkens, look for Orion's sword, a short diagonal line of
three stars below his belt. In the middle of the sword is the Great
Nebula, a cloud of gas and dust still forming into stars.
If you have a good telescope, use high power to look for the
Trapezium, a very compact quadruple star within the Nebula. The
easternmost and westernmost stars of the tight foursome normally
tie for second and third place in order of brightness, at magnitude
6.5. But next Monday, the western star will appear fainter than usual
as it undergoes eclipse by a dim companion star. Look tonight and
again next Monday to see if you can notice any change in the
appearance of the group. For details, see April Sky & Telescope, p. 75.
Friday, April 7
-
As darkness falls the First Quarter Moon is high in the SW with first-
magnitude Procyon 15 degrees to its lower left. The Gemini Twins,
Castor and slightly brighter Pollux, are above the half moon.
The moon is ideal for telescopic observation this weekend. Even
binoculars show much detail. Tonight the sun rises on the trio of
craters Ptolemaeus, Alphonsus, and Arzachel, just below the
midpoint of the moon's terminator (day-night boundary). By
tomorrow evening the craters Plato and Eratosthenes will be in view.
MSU Observatory will be open both nights if skies are clear, after the
8 p.m. showings of The Last Question at Abrams Planetarium.
Saturday, April 8
-
An hour after sunset the moon, past First Quarter, is high in the SSW
nearly between Procyon and the "twins" of Gemini. The Little Dog
Star, Procyon, shines 11 degrees below the moon. Castor and slightly
brighter Pollux are upper right of the waxing gibbous moon. Mars
shines steadily to the moon's upper right.
Sunday, April 9
-
An hour after the Sun sets the gibbous moon is high in the south
with reddish Mars 9 degrees to its upper left. Regulus, in Leo, shines
20 degrees lower left of the moon. Given the moon travels some 13
degrees against the background stars daily, can you predict where
will it appear tomorrow evening at this time?
Monday, April 10
-
An hour after sunset the moon is in SSE with Mars 12 degrees upper
right and Regulus 9 degrees left. In ancient times Regulus, together
with Antares, Fomalhaut, and Aldebaran, were known as the Royal
Stars, each bright star marking a season of the year. Regulus was up
all night at the start of winter, while Aldebaran was up all night in
early autumn. Since ancient times, the dates these stars are up all
night have drifted later in their seasons, to late in February for
Regulus and to the start of December for Aldebaran.
Recall that the moon passed close to Aldebaran 6 nights ago; you can
follow this star in the west until it disappears into twilight glow in
early May. Regulus will follow in late July.
Tuesday, April 11
-
At dusk the moon is in the SE with Regulus 9 degrees to its upper
right. Regulus marks the heart of Leo, and is the bottom star in the
Sickle, representing the Lion's head and mane.
Wednesday, April 12
-
Mercury is at superior conjunction, passing beyond the Sun, in two
days. This elusive planet emerges quickly to begin its best evening
appearance of the year! Begin watching for Mercury shortly after
sunset late next week. During April 20-30, early in its monthlong
apparition, Mercury is nearly fully illuminated and is very bright,
magnitude -1.6 to -0.8.
On Thursday about 45 minutes before sunup, find Venus very low,
between E and ESE. Binoculars will show Saturn only half a degree to
Venus' lower right.
Thursday, April 13
-
An hour after sunset the moon is in the SE with Spica 19 degrees to
its lower left. The moon travels some 13 degrees daily against the
background stars; can you guess where it will be tomorrow evening
at this time?
Friday, April 14
-
The moon, approaching Full, is low in ESE at dusk. Bluish Spica, the
spike of wheat in Virgo, shines 4 degrees to the moon's lower left.
Seen from lower Michigan at 6:00 a.m. EDT on Saturday, the Grass or
Egg Full Moon is low in WSW, and within 15 minutes later will occult,
or cover, Spica!
The Full Moon will occult Spica Saturday morning for most of the
contiguous U.S. except the East. South-central and Midwest U.S. will
see star disappear behind moon after morning twilight gets
underway. For the Great Plains, the disappearance (D) occurs in a
dark predawn sky, but reappearance (R) is in twilight. From the
Rockies westward, both D and R happen in a dark predawn sky. Since
the moon is full, a telescope will be required to see the star's sudden
D or R at the moon's brilliant edge.
For western U.S., a partial lunar eclipse follows the occultation of
Spica by a couple of hours. In the Pacific Time Zone, the moon begins
to enter the Earth's umbra (dark inner shadow) Saturday at 4:41 a.m.
PDT. Deepest eclipse occurs at 5:18 a.m. PDT, with only the
southernmost 1/8 of the moon's width in shadow, and Spica about
one degree to the moon's west. The moon leaves the umbra at 5:55
a.m. PDT. The entire umbral eclipse is visible in Hawaii, Alaska, and
the rest of the U.S. west of a line from central Arizona to Idaho's
panhandle. From that line eastward through Texas and the Dakotas,
the moon sets with the umbral eclipse in progress. Farther east, none
of the umbral eclipse can be seen.
For more details on these two events, see the April issue of Sky &
Telescope, p. 68-69.
Saturday, April 15
-
The moon, now past Full, rises in the ESE some 35 minutes after
sunset. Spica shines 10 degrees to the Moon's upper right. In the
brightening dawn on Easter Sunday, the waning gibbous moon is low
in the SW, with Spica 14 degrees to its lower right.
Sunday, April 16
-
An hour before sunrise Monday the waning gibbous moon is in the
SW, approaching Jupiter and Antares. Bright Jupiter gleams 22
degrees upper left of the moon. Antares, 17 degrees to the moon's
left and within 8 degrees lower right of Jupiter, represents the heart
of the Scorpion.
Monday, April 17
-
The moon pulls nearly even with Antares an hour before sunup
Tuesday. Look for the moon in the SSW with bright Jupiter 7
degrees to its left. Reddish Antares twinkles within 7 degrees lower
left of moon and within 8 degrees lower right of Jupiter.
Tuesday, April 18
-
An hour before sunup Wednesday the moon, just west of due south,
has passed bright Jupiter. The brilliant planet, of magnitude -2.4, lies
8 degrees lower right of the moon. Antares, in Scorpius, twinkles to
their lower right.
Wednesday, April 19
-
How many more evenings will the bright stars of winter remain
visible? Within an hour after sunset in the coming weeks, watch
Rigel, the Pleiades, Aldebaran, Sirius, and Betelgeuse sink into the
western twilight glow. Keep a daily log of your observations, and try
to see each star until its last possible date.
Thursday, April 20
-
Mars is high in the S at dusk and continues to fade rapidly, from
magnitude +0.3 tonight to +0.9 at the end of May. From now until
May 17, Mars is more than 800,000 miles farther from Earth with
each passing day. Watch Mars close in on Regulus, now 13 degrees to
the planet's left. By month's end the two are within 10 degrees.
Friday, April 21
-
Mercury passed superior conjunction, beyond the Sun, only one week
ago. Can you see it yet? Look early, half an hour after sunset, for this
elusive planet very low in the WNW. Binoculars help during the first
few evenings of its visibility. The moon, near Last Quarter, is in the
SSE at dawn Saturday.
Saturday, April 22
-
With binoculars and a detailed finder chart, it's possible to spot faint
5.8-magnitude Uranus. It's visible low in SE in the constellation
Capricornus before dawn's first light. Our April Sky Calendar
included a finder chart with instructions to starhop to Uranus in
April-May. For a free copy, send a long, self-addressed stamped
envelope to Planet Finder, c/o Abrams Planetarium, Michigan State
University, East Lansing, MI 48824.
Sunday, April 23
-
Can you spot Saturn yet? Look for it very low, between E and ESE,
about 45 minutes before sunrise. On Monday it is 12 degrees upper
right of brilliant Venus in the E, and 19 degrees lower left of moon in
ESE. Saturn's rings have now closed to only 1 degree from edge-on,
causing the planet to fade to magnitude +1.2. Saturn's low altitude at
dawn makes for difficult telescopic viewing of the needle-like rings.
Monday, April 24
-
Forty-five minutes before sunrise Tuesday, the moon is low in the
ESE with Saturn 7 degrees to its lower left. Note the old crescent
"bowl" appears tipped on its side, as if pouring its water out.
Brilliant Venus is very low in the E, 19 degrees lower left of the
crescent. If you can't spot Venus, wait another quarter hour as the
planet rises higher in dawn's glare.
Tuesday, April 25
-
The slender crescent moon is low in the E 45 minutes before sunup
Wednesday, with Saturn 8 degrees to its right. The morning "star"
Venus has just risen 8 degrees to moon's lower left. The moon's
motion averages 13 degrees against the background stars daily. Can
you guess where will it appear at the same time on Thursday?
Wednesday, April 26
-
The thin crescent moon has overtaken Venus very low in the E half
an hour before sunup Thursday morning. From northern states, this
is the last easy chance to see the Old Moon at the end of the current
cycle. Locate Venus about 5 degrees to the moon's right.
Thursday, April 27
-
On Friday morning, about 25 minutes before sunrise, try for the Old
Moon barely risen. From northern states, binoculars will be needed
to locate the thin crescent in bright twilight. Look 12 degrees north
of east and 16 degrees lower left of Venus. Observers in southern
states should be able to see this old moon with unaided eye.
Friday, April 28
-
National Astronomy Day is Saturday, May 6, and many planetariums
and amateur astronomy clubs will hold activities that weekend to
commemorate the occasion. Check the September 1994 issue of Sky
& Telescope magazine for planetariums and clubs in your area, then
make contact and join in on their activities!
To celebrate the weekend, Abrams Planetarium will present Spring
and Summer Skies, on Friday and Saturday, May 5 and 6, at 8:00
p.m., and on Sunday, May 7 at 4:00 p.m. If skies are clear after the
Friday and Saturday evening shows that weekend, the MSU
Observatory will be open for telescopic viewing of the moon and
other celestial objects.
Saturday, April 29
-
The moon is New today, and is too near the Sun to be seen, except in
silhouette from places where today's solar eclipse can be seen. In a
narrow track across northern South America, the moon passes
directly across the face of the Sun, causing an annular or "ring"
eclipse. From the U.S., only the Florida peninsula will witness
anything of this eclipse, with the moon taking a small "bite" out of
the Sun's lower limb. From Miami, only 12 percent of the Sun's
diameter will be covered at greatest eclipse, around 2:10 p.m. EDT.
Floridians should check with their local planetarium for information
on safe viewing methods.
At dusk, ruddy Mars is high in the SSW with first magnitude Regulus
10 degrees lower left.. The pair will be at their closest, 1 degree
apart, in 25 days. Keep watching!
Sunday, April 30
-
Look early, half an hour after sunset, for the Young Moon very low in
the WNW. Binoculars give the best view of the delicate crescent.
Elusive Mercury is 5 degrees upper right of the crescent, while the
Pleiades star cluster shines 3 degrees above Mercury. Aldebaran in
Taurus twinkles 14 degrees to Mercury's upper left.