April 2015


April is a great month for casual star gazing. The weather is tolerable, it still gets dark at a reasonable hour, and the evenings are relatively bug free. Be sure to take every opportunity to just go outside and look up. Star gazing is just that easy. As interest is piqued, spend some cloudy nights reading about anything that you’ve seen night sky.

About Scope Out      How to begin Observing the Night Sky


The sky map below represents the sky as it will appear in mid-April  at the end of astronomical twilight, or the arrival of complete darkness, at 9:20pm EDT. The Scope Out monthly focus is on the constellations that are  just to either side of the meridian, which is near the 10th hour (10h) of right ascension line in the April sky map. For a primer on how to use this sky map, please read How to begin Observing the Night Sky.

Scope Out divides the celestial sphere into three zones to aid in finding constellations:

1. Circumpolar Constellations: Find Lynx, Perseus, Camelopardalis, and Ursa Major in the northern sky above Polaris.

2. Northern Constellations:  Orion continues to move toward the western horizon. Although it no longer dominates the sky, it does catch they eye before setting below the western horizon about an hour or so after sunset. Find April’s remaining northern constellations, Cancer, Leo, and Leo Minor near the zenith.

3. Southern Constellations: The best-placed constellations in April are Hydra, Sextans, Pyxis and Crater. Some of these, Pyxis and Crater, for example, never rise very far above the horizon because of their deep southern declination.

The April Sky at Nightfall. Jim Johnson, December 2014.


Colors of the planets. This picture is not to scale. Image from NASA’s Planetary Photogrounal at http://photojournal.jpl.nasa.gov/

Mercury begins its best evening apparition during the last week April. Look for it low on the western horizon about 45 minutes after sunset. It reaches its best viewing opportunity during the first week of May. Mercury and Mars put on a planetary show on the western horizon around April 20th, and can be seen with binoculars soon after sunset. Venus’ brightness will dominate the western sky after sunset, and will continue to appear a little higher above the horizon each evening.  It will move through Taurus passing near the Pleiades and Hyades around mid-month. Jupiter is in its best nightfall view position near the meridian at sunset. Saturn continues to rise earlier each evening, appearing above the eastern horizon about two hours after sunset. Uranus is lost in the Sun’s glare and will soon reappear as a morning object. Neptune is now a morning object, but it is still too close to the Sun’s glare to be seen before dawn.


moon_phases_small_full April 4
Full Moon
April 8
Conjunction with Saturn
moon_phases_small_lastqtr April 12
Last Quarter
moon_phases_small_new April 18
New Moon
April 19
Conjunction with Mars and Mercury
April 20 and 21
Conjunction with Venus
moon_phases_small_firstqtr April 25
First Quarter
April 25 and 26
Conjunction with Jupiter


Lunar Eclipse – April 4th

The eclipse begins when the moon enters the prenumbra of the Earth’s shadow at 5:35am EDT. The partial eclipse begins when the moon enters the umbra of the Earth’s shadow at 6:15am, and totality begins when the moon is completely enveloped within the umbra at 7:54am. The moon, when viewed from Maryland, sets a few minutes later, which is before the moon emerges from the umbra.

Venus Passes near Pleiades – April 11th

Venus passes within 3° of the Pleiades. Not many lay observers have actually witnessed a planet’s wanderings among the fixed stars, so watch Venus all month to view its progression between the Pleiades and Hyades. The moon will pass through this area of the night sky on the 20th and 21st of April.

Conjunction with Mercury and Mars – April 19th

This will be a very difficult conjunction to view, because the very young moon and the two planets will lie very close to the Sun at sunset. The view will be spectacular for those lucky enough to have a clear view all the way down to the horizon on this evening.

Lyrid Meteor Shower – April 22nd

This is not one of the better meteor showers of the year, but meteor enthusiasts will not want to miss it. The best time to observe is from 11pm until dawn.


© James R. Johnson, 2015

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