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Astronomy in April: A Pair of Comets


Two comets are in the nighttime skies in April, one lingering after sunset and one appearing before sunrise. Comet PanSTARRS made its debut appearance in the Northern Hemisphere in March as it began to appear in the sunset’s glow midmonth. The comet is dimming as it moves out of the solar system, so use binoculars or a telescope to try to track it down. In April it will be crossing through the region of Andromeda, heading toward the North Star.

Comet PanSTARRS's biggest event of the month will be on April 3, when it passes a few degrees from the Andromeda Galaxy, M31. Binoculars or a wide-field telescope will give the best view of this fuzzy pair of objects.

Comet Lemmon is the second good comet of the year, also beginning its show in the Southern Hemisphere before moving into northern skies around April 19. The comet is expected to shine around 4-5th magnitude, similar to a dim star.

Both Comet PanSTARRS and Comet Lemmon will occupy the same region of sky but at different times. Comet PanSTARRS passes through Pisces, moving from left to right in March in the west at sunset. Comet Lemmon also passes through Pisces, moving from right to left in late April in the east at sunrise. Both comets are once-in-a-lifetime for Earthly observers, with Comet Lemmon’s first chance of returning 11,000 years from now, and Comet PanSTARRS 110,000 years from now, if it returns at all.

For observing that doesn’t require optical aid in April, look to the planets. Saturn reaches opposition on April 28, rising in the constellation Libra in the east-southeast. Saturn lies to the lower left of Spica, the brightest star in Virgo, with an even brighter star, Arcturus, to the upper left of Saturn. But Saturn outshines them both. Watch the moon pass Spica on April 24 and Saturn on April 25, when the moon is full. A lunar eclipse on this date will be visible in the Eastern Hemisphere, and Northern American viewers are completely shut out.

Jupiter is another planet that is easy to find using only your eyes. Note especially April 14 when the moon lies near Jupiter. The bright planet lies high in the west throughout the month but it's dropping closer to the horizon as it prepares for a rare trio of planets meeting in May. Venus is slowly emerging from the sun at sunset, climbing higher in the sky to meet Jupiter, and Mercury will join them at the last minute.

Meteor shower "season" begins to pick up in April after a mostly quiet start to the year as the Lyrids peak overnight on April 21. The April Lyrids are not particularly strong, with a zenithal hourly rate (ZHR, or expected meteors per hour) at 12. However, Lyrids can be spotted anytime between April 19 and 24, giving observers a fair chance of catching one while enjoying the evening sky over a week. Emanating from the constellation Lyra, the meteors are the product of a comet known as Thatcher that once left behind a stream of debris that we pass into each April.

(Photo: Comet PanSTARRS as seen in March 2013. Credit: John Chumack)

HS_KellyWhittKelly Kizer Whitt loves clean, clear, and dark skies. Kelly studied English and Astronomy at the University of Wisconsin-Madison and worked for Astronomy magazine. She writes the SkyGuide for AstronomyToday.com. You can follow her on Twitter at twitter.com/Astronomommy.

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