Astronomy: The Week Ahead – Sun 03 May to Sat 09 May


Sunday May 03

Tonight is a planetary show! The moon is full at 20:42 PDT. This full moon’s names are Full Flower Moon, Full Corn Planting Moon or Milk Moon. It is the season of abundance. Watch it rising in the east as the sky darkens, followed by Saturn in an hour eighteen degrees east. Look west in the darkening twilight to find Jupiter high above brilliant Venus low to the west, and Mercury skimming the horizon below Venus to the right. Spring has just one more full moon, then summer observing season begin!


Monday May 04

Jupiter was at Eastern Quadrature at 1:44 a.m. today, at a right angle to the sun from the earth. Jupiter observing season is quickly coming to a close for 2015. Tonight you can enjoy the last part of a shadow transit of Io, and a view of the Great Red Spot (GRS) as the giant planet slides toward the western horizon and sunset. Don’t wait till it’s dark, or the shadow transit will be over.


Tuesday May 05

Rising in the east on early May mornings is the constellation Pegasus, the Winged Horse. Its famous asterism, The Great Square, is marked on its corners by the bright stars Alpheratz, Algenib, Markab and Scheat. Trailing off the northern corner star Alpheratz is a pair of star chains, defining another famous constellation, which shares Pegasus’ star Alpheratz.


Wednesday May 06

Mercury is at its greatest elongation tonight during sunset at 20:30 PDT. Occasionally the universe puts on a beautiful celestial show, and tonight is such an evening, with Orion bidding us adieu sinking into the sunset for another season, Mercury, Venus and Jupiter forming an ascending display rising toward nightfall. Go out and enjoy this excellent view!


Thursday May 07

Galaxy season is well upon us, with Downtown Virgo being where the action is. Located between the stars Vindemiatrix in Virgo, and Denebola in Leo, M84 and M86 are central in the Virgo Galaxy Cluster, approximately 45 million light years distant. Get yourself to a darker sky, set up your telescope and enjoy the show. You’ll find yourself galaxy hopping, instead of star hopping, in this busy part of the sky!


Friday May 08

Tonight Venus is in conjunction with the great open cluster M35 in Gemini. At less than two degrees separation, they will fit easily in a binocular field of view. If you have a wide field eyepiece, they should form a spectacular pair together at low magnification. Don’t forget to peek for Mercury too, skimming the western horizon as twilight darkens.


Saturday May 09

Look for Hercules and Ophiuchus in the predawn skies today. Their Alpha (brightest) stars sit very close together in our sky, and they share similar Arabic names. Rasalhague shines at magnitude 2.1, and is only 47 light years distant, truly a neighbor of ours. Rasalgethi is dimmer, at 2.75, and much more remote at distance of 384 light years. Rasalgethi is also an excellent double star in a telescope. The primary is a variable star, ranging from magnitude 3.0 to 4.0. Its companion is separated by 4.6 arcseconds – resolvable in most telescopes, shining at magnitude 5.4. They orbit each other over a 3600 years period.

Happy viewing!