(Viewed 1,649 times)

[Chicago Astronomer - Astro Joe]

4/2 The crescent Moon is 0.33 degree north of the center of the
bright open cluster M45 (the Pleiades) at 00:00 - occultations and
grazing occultations of some of M45's stars take place in eastern and
central North America and the Caribbean; Daylight Saving Time begins
at 7:00

4/3 Mars is 3.5 degrees south of the Moon at 19:00; maximum lunar
libration of 9.6 degrees occurs at 21:00

4/5 A double shadow transit of Jupiter by the Galilean satellites
Io and Ganymede begins at 9:30; Saturn is stationary in right
ascension, with direct (eastward) motion to resume, at 12:00; First
Quarter Moon occurs at 12:01

4/6 The Moon is 1.7 degrees south-southwest of the first magnitude
star Pollux at 3:00

4/7 Mercury reaches its greatest illuminated extent (23"); Saturn
is 3.8 degrees south-southwest of the Moon at 1:00; the Moon is 2.9
degrees north-northeast of the bright open cluster M44 (the Beehive
Cluster) at 7:00; Mercury is at aphelion at 23:00

4/8 Mercury is at greatest western elongation (27.8 degrees) at
19:00

4/9 The Moon is 2.5 degrees north-northeast of the first magnitude
star Regulus at 5:00; the Moon is at apogee, subtending 29'28" from a
distance of 405,551 km, at 13:00

4/11 Minimum lunar libration of 1.6 degrees occurs at 7:00

4/12 The Moon is at the descending node (longitude 184.4 degrees) at
2:36; the Moon is at its greatest declination north (25.1 degrees) at
9:00; Venus is at the descending node of the ecliptic at 17:00

4/13 Full Moon, known as the Egg or Grass Moon, occurs at 16:40; the
Moon is 0.37 degree east-northeast of the first magnitude star Spica
at 18:00 - an occultation takes place in southern Asia and northern
Australia

4/15 Jupiter is 4.8 degrees north-northeast of the Moon at 12:00; the
equation of time is equal to 0 (i.e., sundial time and clock time are
the same) at 18:00

4/16 The Galilean satellite Ganymede reappears from eclipse at 5:26;
Ganymede is occulted by Jupiter at 5:36

4/17 The Moon is 0.33 degree west-southwest of the first magnitude
star Antares at 8:00 - an occultation takes place in southern South
America; Mars is 0.7 degree north of the center of the bright open
star cluster M35 at 16:00

4/18 Venus (-4.2 magnitude) is 0.33 degree north-northwest of Uranus
(5.9 magnitude) at 9:00; Venus and Uranus are separated by only 18'
at 10:00; maximum lunar libration of 9.0 degrees occurs at 17:00

4/19 The Sun enters the constellation of Aries (ecliptic longitude
28.91 degrees) at 3:00

4/21 Last Quarter Moon occurs at 3:28

4/22 The peak of the Lyrid meteor shower (20/hour) occurs at 16:00;
Neptune is 3.5 degrees north-northwest of the Moon at 12:00

4/24 Uranus is 1.1 degrees north-northwest of the Moon at 3:00 - an
occultation takes place in southern South America, South Island New
Zealand, and southeastern Australia; Venus is 0.47 degree west-
northwest of the Moon at 14:00 - an occultation takes place in most
of South America and southeastern West Africa

4/25 Saturn is at eastern quadrature (i.e., it is 90 degrees east of
the Sun) at 1:00; minimum lunar libration of 0.4 degree occurs at
9:00; the Moon is at perigee, subtending 32'51" from a distance of
363,731 km, at 11:00; the Moon is at the ascending node (longitude
4.1 degrees) today

4/26 Mercury is 3.5 degrees south-southeast of the Moon at 5:00

4/27 New Moon (lunation 1031) occurs at 19:44

4/28 Mercury is its greatest heliocentric latitude south (-7.0
degrees) at 6:00

4/29 The Moon is 0.35 degree west-northwest of M45 at 10:00
4/30 May Eve, a cross-quarter day; Mars is at heliocentric
conjunction with Saturn (heliocentric longitude 131.2 degrees) at 3:00

Times and dates for the lunar light rays predicted to occur this
month are available at www.lunar-
occultations.com/rlo/rays/rays.htm

A major lunar event occurs on April 1. Look to west about 45 minutes
after sunset to see the old Moon in the new Moon's arms occult some
of the stars of the Pleiades.

The planets on April 1: Mercury (0.5 magnitude, 8.8", 35%
illuminated), Venus (-4.3 magnitude, 22.8", 53% illuminated), Mars
(1.2 magnitude, 5.7", 91% illuminated), Jupiter (- 2.4 magnitude,
42.9", 100% illuminated), Saturn (0.1 magnitude, 19.1", 100%
illuminated), Uranus (5.9 magnitude, 3.4", 100% illuminated), Neptune
(7.9 magnitude, 2.2", 100% illuminated), and Pluto (13.9 magnitude,
0.1", 100% illuminated).

Morning planets: Mercury, Venus, Uranus, Neptune, and Pluto

Evening planets: Mars, Jupiter, and Saturn

For observers in the northern hemisphere, Mercury puts on a poor
morning apparition this month.

Still shining brightly, Venus rapidly shrinks 6" in apparent size
during April. Venus and Uranus have a close encounter of the
planetary kind just before daybreak on April 18.

Mars is positioned between Beta and Zeta Tauri, the stars at the ends
of the horns of Taurus, on April 1. The Red Planet is only some 5"
in size as it travels eastward along the ecliptic. By April 17, it
will be within 1 degree of M35 in Gemini and on April 30 it will be
even closer to third magnitude Epsilon Geminorum.

Jupiter, in Libra, rises just after sunset by month's end. It lies
less than 1 degree north of Zubenelgenubi on April 25. The Great Red
Spot (GRS) has a new red companion, or perhaps more accurately pale
pink, the result of an unexpected change in color of the white oval
known as BA. Dubbed Red Junior and Red Spot Junior, it's about half
the size of the GRS and is located in the South Temperate Belt. Red
Junior lags behind the GRS by about an hour. In order to determine
the transit times of the GRS, click on
skyandtelescope.com/observing/objects/planets/article_107_1.asp


Dimming slightly, Saturn resumes its eastward course towards M44 on
April 5. After reaching quadrature on April 25, the shadow of
Saturn's globe is cast farthest sidewards onto its rings, resulting
in the illusion of greater depth. Titan (8.4 magnitude), Saturn's
largest satellite, is directly north of the Ringed Planet on April 6
and April 22. It's due south of Saturn on April 14 and April 30.

Uranus moves 1 degree northeastward, from 1 degree east of fourth
magnitude Lambda Aquarii to quite close to the sixth magnitude star
81 Aquarii, in the span of a month.

During April, Neptune resides some 2 degrees northeast of fourth
magnitude Iota Capricorni.

Located in Serpens, Pluto is more easily observed in the coming
months.

On the night of April 3, asteroid 4 Vesta (7.9 magnitude) passes
approximately 25' north of 37 Geminorum. Vesta dims from 7.8 to 8.1
magnitude as it tracks eastward between the first magnitude star
Pollux and the third magnitude star Epsilon Geminorum.

Comet 73P/Schwassmann-Wachmann 3 broke into 4 major pieces in 1995.
The possibility exists that as a result the comet could brighten to
as much as second magnitude in May. During April, it may glow at
seventh magnitude as it passes through Corona Borealis.

Comet C/2006 A1 (Pojmansk), which displayed a dim but moderately long
gas tail as it graced the eastern morning sky in early March, travels
rapidly to the northeast, eventually passing through Cassiopeia.