You are hereTHIS MONTH’S SKY - April 2012

THIS MONTH’S SKY - April 2012


THIS MONTH'S SKY

Celestial Events -- April 2012

 

VENUS AND THE PLEIADES

If you regularly look at the sky in the evening, you will have seen Venus dominate the western sky, moving higher with each day.

The highlight of this apparition of Venus occurs on April 3rd, as it passes just to the left of the beautiful Pleiades star cluster. If you've never seen the cluster, this is the night. Unless you have a wide-field telescope, you're actually better off with binoculars, since the Pleiades are widely scattered.

Enshrouded in clouds, on April 3 Venus will have a diameter of 25.2 arcminutes, a phase (percentage lit) of 46% and a magnitude of -4.5. If the weather is bad on the 3rd, Venus will be almost as beautiful a few days before or later.



Chart 1. Venus's path
in Early April

 



Chart 2. Close-up.
Venus and the Pleiades on April 3rd.
 

 


APRIL'S EVENING SKY

 

Click to get sky charts and a description of the sky for this month.
 


PLANETS IN APRIL

MERCURY is in the morning sky. At this time of year the planet is in the southernmost constellations of the zodiac, and thus almost invisible to the naked eye. It is at greatest western elongation (27° from the Sun) on April 18, and

VENUS (magnitude -4.5 on April 1st to -4.7 on April 30th, diameter 24.8" to 36.9", illumination 48% to 28%) is still very high in the west. On April 3rd it passes just below the Pleiades (see above). During the month it moves through Taurus, approaching Beta Tauri in early May.

MARS (magnitude -0.7 to -0.1, diameter 12.6" to 10.0", illumination 97% to 92%), in Leo, is stationary on April 15th, resuming direct motion. Compare its movement with respect to the nearby bright star Regulus -- they are 5.4° apart on the first of the month,  4.3° when closest on the 15th, and 5.5° at the end of April.

JUPITER (magnitude -2.1 to -2.0, diameter 33.9" to 32.9") is in Aries. It is easy to spot below Venus in the western sky. However, it is rapidly getting lower, setting 2 hours after the Sun as April begins, but only 45 minutes after when April ends.

SATURN (magnitude +0.3, diameter 19.0") is at opposition on April 15 in Virgo. Like Mars, Saturn has Spica, a bright nearby star that can be used to detect change in position. During April the distance between Saturn and Spica decreases from 5.8° to 4.9°.

URANUS (magnitude +5.9, diameter 3.4") is in bright twilight. It is closest to Mercury (2°) on April 22 (a very difficult observation). As it escapes from the Sun it becomes somewhat easier to see.

NEPTUNE (magnitude +7.9, diameter 2.2") can be seen with a telescope in the morning sky.

PLUTO (magnitude +14.1, diameter 0.1") is in Sagittarius, visible with a large telescope. It begins retrograde motion on April 10.

See below for phases of the Moon and the Moon's conjunctions with planets and bright stars.



THIS MONTH'S EVENTS
(Times in EDT)
 

April 3 Moon passes 9½° below Mars and Regulus.
  VENUS IS ½° BELOW THE PLEIADES.
April 6 Full Moon at 3:19 PM. It is 2½° below Spica and 8½° below Saturn.
April 7 Moon passes 6° south of Saturn.
April 10 Moon passes 4° above Antares this morning.
  Pluto is stationary, beginning retrograde movement.
April 13 Last Quarter Moon at 6:50 AM.
April 15 Mars is stationary, resuming direct motion.
  Saturn is at opposition.
April 16 Venus passes 10° above Aldebaran.
April 18 Mercury is at greatest elongation in the morning sky.
April 21 New Moon at 3:18 AM.
April 22 Lyrid meteor shower peaks.
  Moon passes 2° above Jupiter.
April 24 Moon passes 6° below Venus.
April 29 First Quarter Moon at 5:57 AM.
April 30 Venus is at greatest brilliancy (magnitude -4.7).
  Moon passes 6° below Regulus and 9° below Mars.