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General Information May 2016 This Month: The early evening sky straddles three seasons, with those of Spring occupying the central view. Jupiter is joined by Mars and Saturn, which rise in the late evening hours as the month begins. All three will continue to be visible in the night sky through the end of July. As night falls, the Milky Way lies low along the horizon in all directions, our oblique view through more of the atmosphere rendering it virtually invisible. Sunset Range: 8:10 p.m. (May 1st) to 8:34 p.m. (May 31 st ). End of Astronomical Twilight (Full Darkness* – Sun 18° below horizon): 9:48 p.m. (May 1st) to 10:25 p.m. (May 31 st ). * Usually dark enough for observing about a half hour before this.

Moon Phases May 2016 Fri., May 6 th – New Moon (Observing at Cahas on May 6 th and 7 th ) Fri., May 13 th – First Quarter Moon Sat., May 21 st – Full Moon Sun., May 29 th – Last Quarter Moon (Observing at Cahas on May 27 th and 28 th ) Roughly speaking: First Quarter Moon is highest at sunset and sets at midnight Full Moon rises at sunset and is in the sky all night Last (or “Third”) Quarter Moon rises at midnight and is highest at dawn New Moon sets at sunset and is absent from the sky all night

Celestial Events May 2016 Sun., May 1 st – “May Day” (or “Beltane”); halfway between Spring equinox and Summer solstice. Sat., May 7 th – Extremely thin crescent Moon (2% illum.) 17° from setting Sun (on Sunday, the 8 th, the Moon is 6% illum. and 30° from Sun). Mon., May 9 th – TRANSIT of MERCURY! Mon., May 9 th – Jupiter stationary in right ascension; resumes direct (i.e. eastward) motion against background stars. Sun., May 22 nd – Mars at opposition. Mon., May 30 th – Mars nearest to Earth (0.503 AU); closest and largest (18.6“) for over ten years.

Moon N W Meridian Jupiter E S Directly Overhead (“zenith”) May 15 th, 9:30 p.m. (~30 min. before full darkness) Callisto Io Europa Ganymede

Moon N W Jupiter E S May 15 th, 9:30 p.m. (~30 min. before full darkness) Callisto Io Europa Ganymede Mars Saturn rises at 9:40 p.m. but won’t be at least 20° high until about midnight.

Moon N W Jupiter E S Pollux Castor May 15 th, 9:30 p.m. (~30 min. before full darkness) Early Summer Mars Spring Late Winter Spanning Three Seasons Castor BA C NGP M3 Cor Caroli Arcturus M5 Image courtesy of the Isaac Newton Group of Telescopes, La Palma Image courtesy of Fred Calvert, Cold Spring Observatory, Cold Spring, Kentucky Capella Betelgeuse Procyon

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