Astronomy Club of Asheville April 2017 Sky Events

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1 April 2017 Sky Events The Planets this Month page 2 April 6 th - Regulus and the Gibbous Moon page 5 April 10 th -The Full Moon Joins Jupiter and Spica page 6 Planet Highlights page 7 Moon Phases page 10 April 21 st -22 nd the Lyrid Meteor Shower page 11

2 April 2017 Sky Events the Planets It seems as if Mars has been our constant companion in southwestern-western skies at dusk for months and that s because it has! The red planet s motion through the solar system, as seen from Earth, has almost paralleled its motion through the seasonal changes of the stars, thus keeping Mars in relatively the same position in our skies since last summer. At more than 215 million miles away and appearing only 4.2 arcseconds in diameter, though, Mars will be telescopically unremarkable until 2018, when a more favorable alignment with the Earth will provide better views. Look low to the west about 45 minutes after sunset for a naked eye glimpse of this planet. Mercury joins Mars after sunset for the first ten days of April.

3 April 2017 Sky Events the Planets Mercury reaches greatest elongation east of the Sun (19 ) on April 1 st. It will then be seen progressively lower on the horizon at dusk as it approaches an April 20 th inferior conjunction, when its orbit passes between the Earth and the Sun. Find the Winged Messenger very low to the western horizon, about minutes after sunset. Binoculars will be particularly helpful to locate Mercury out of twilight s glow. Jupiter makes a welcome entrance to mid-evening skies in April, rising about 8:45 p.m. EDT on April 1 st. By month s end the solar system s largest planet should be visible shortly after sunset in the southeast, shining brightly at magnitude Jupiter reaches opposition the closest position to Earth for the year (at only 419 million miles!) on April 7 th and thus the most dynamic object in our skies will delight from sunset to sunrise.

4 April 2017 Sky Events the Planets Saturn, found in the constellation Sagittarius, remains a target for early-risers, appearing in the southeast-south skies about 2:30 a.m. EDT. By late April the ringed planet will hover high near the meridian before dawn. Venus has now transitioned to the morning star and is seen rising about 1 hour before sunrise, low to the east. Its illuminated crescent, glowing at -4.2 magnitude, will brighten to -4.7 throughout the month. Uranus reaches conjunction (on the opposite side of the Sun as seen from the Earth) on April 14 th and will be lost in the Sun s glare all month. Neptune reemerges from the Sun s glare late in the month, appearing in the eastern dawn skies by the last week in April.

5 April 2017 Sky Events Regulus and the Gibbous Moon The evenings of Thursday, April 6 th, and Friday, April 7 th, will provide a fine opportunity to let the waxing gibbous moon guide you to the bright 1 st magnitude star Regulus, found in the constellation Leo the Lion. Sometimes thought of as the Heart of the Lion, this bluish star is four times larger than our own Sun and 77 light years distant. Its name comes from the Latin for little king or prince. On these nights, look high in the southeast about one hour after sunset for a regal lunar conjunction! Image courtesy of Sky & Telescope

6 April 2017 Sky Events the Planets The Full Moon Joins Jupiter and Spica On the evening of Monday, April 10 th, the nearly full Moon pairs with Jupiter and the bright star Spica in the constellation Virgo. Our two dimensional view, as seen from the Earth, belies the fact that the Moon is 245 thousand miles away on this evening, while Jupiter is some 414 million miles distant and Spica is 250 light years away! Look well above the east-southeast horizon around 8:30 p.m. EDT to catch this view. Image courtesy of Sky & Telescope

7 April 2017 Planet Highlights Planet Distance from Earth Constellation(s) Diameter in arc seconds Magnitude Comments Page 1 of 3 Mercury 0.7 AUs Pisces & Aries Reaches inferior conjunction on Apr. 20 th Venus 0.4 AUs Mars 2.3 AUs Pisces Found all month low in the east at dawn. Aries & Taurus Positioned in the west at dusk.

8 April 2017 Planet Highlights Planet Distance from Earth Constellation(s) Diameter in arc seconds Magnitude Comments Page 2 of 3 Jupiter 4.5 AUs Virgo Reaches opposition on April 7 th ; visible all night this month. Saturn 9.6 AUs Sagittarius Positioned in early morning S-SE skies. Uranus 20.9 AUs Pisces In conjunction with the Sun on Apr. 14 th.

9 April 2017 Planet Highlights Planet Distance from Earth Constellation(s) Diameter in arc seconds Magnitude Comments Page 3 of 3 Neptune 30.7 AUs Aquarius Visible in early morning by late April.

10 The Moon April 2017 First Quarter 3 rd 2:39 p.m. Full Moon** 11 th 2:08 a.m. Last Quarter 19 th 5:57 a.m. New Moon 26 th 8:16 a.m. ** The Pink Moon Unless otherwise indicated, all times are EDT

11 April 2017 Highlight - The Lyrid Meteor Shower The annual Lyrid Meteor Shower peaks this year on the night of April 21 st and in the early morning hours of April 22 nd,with minimal interference from a waning crescent Moon. You can expect 10 or more meteors per hour from a dark and open location from 11:00 p.m. until dawn. On this night Earth is passing through the debris trail of Comet Thatcher (C/1861 G1). This comet (the source of the meteors) has a 415 year orbit about the Sun, and it was discovered by A. E. Thatcher in The Lyrid meteors will appear to radiate from the direction of the sky where the constellation Lyra, the Harp, is located which gives the meteor shower its name.

12 April 2017 Highlight The Lyrid Meteor Shower The view around 1:30 a.m. on Apr. 22

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