What's Up in the Night Sky

June 2013 - Vol. 17, No. 6

This Month's Night Sky - NOTE: The next paragraph describes the sky as it appears at 10 pm EST (11 pm EDT) near mid- month. The sky also looks this way at 11 pm EST (midnight EDT) during the beginning of the month and at 9 pm EST (10 pm EDT) by month's end.

This Spring has granted us a feast of bright planets, did you enjoy the show in the western sunset sky at the end of May? It continues in June, so keep looking up! Spica (Virgo) glows in the SW while Regulus (Leo) vanishes over the W horizon before midnight. The "big dipper" (Ursa Major's asterism) now stands on its "handle" in the N. Antares (Scorpius) is low on the S horizon. The E sky is dominated by the "summer triangle" asterism: Deneb (Cygnus), Vega (Lyra) and Altair (Aquila). An interesting star tour begins at the last star of the big dipper's handle, Alkaid. Following the curve of the handle, "arc to Arcturus". Now, following the same curve, "spike to Spica" and "continue to Corvus", its distinctive four star, kite-shaped, asterism.

MERCURY starts out the month at -.3 magnitude, but fades to +1.0 by mid-June. VENUS visible in the evening sky, moves through Gemini and into Cancer. The inner planets will be near the beehive cluster in Gemini early in the month. JUPITER vanishes this month from the sunset sky reaching conjunction on the 19th. MARS becomes visible in morning twilight late this month. SATURN still visible most of the night, fades during morning twilight.

Review how to determine Angular Measurement.

Calendar of Events

NOTE: For those observers not in the ET zone, convert the calendar times to your zone's time by subtracting one hour for CT, two for MT and three for PT. Don't forget to adjust for Daylight Savings Time when necessary by subtracting one hour from your planisphere's time. Dawn and dusk times must also be corrected. See your local newspaper, TV news, or cable TV's Weather Channel for sunrise and sunset times. Unfortunately some of these events may occur during daylight hours in your area.

DATE	EVENT
01	Mecury 1.3 deg. N of M35.
04	Venus in M35.
09	Moon at apogee.
10	Venus 5 deg N of the Moon. Mercury 6 deg N. of Moon.
12	Mercury at greatest E. elongation.
14	Moon at apogee. Regulus ~6 deg N. of the Moon.
15	Mercury 6 deg. S of Pollux.
18	Spica .1 deg S. of the Moon, occultation in S. America, Carribean and parts of Western Africa.
19	Jupiter in conjuction with the Sun, Saturn 4 deg N of the Moon.
20	Solstice!
23	Moon at perigee, on this date the closest full moon of 2013 will be visible all night.
24	Mercury hugs the horizon after a very impressive late Spring show.
27	Castor, Pollux and Venus, setting with the Sun. Say good-bye to the twins for awhile as the bright summer twilight hides them from view.
30	Can you find Mars in the morning sky? You'll find the red planet in Taurus, but take care not to look at the Sun.

Lunar Almanac for June 2013

Phases of the Moon	Phase and Date(s)	Best viewed before local midnight
	New 08	Deep Space Objects
	1st. Qtr 16	Planets & Moon
	Full 23	Moon
	Last Qtr 30	Deep Space & Planets

Topic of the month: Arcturus and Boötes

Star light, star bright, first star I see tonight...

If you are located on Earth's northern hemisphere, the first star you've been seing on these Spring evenings, is the first magnitude orange star Arcturus, locate in the ancient constellation of Boötes. Arcturus has the distinction of being the brightest star north of the celestial equator. It also has a high proper motion, the highest of any first magnitude star. this is due to the fact that it is nearby, but does not belong to the cluster of stars our sun is associated with, instead, it has given its name to a stream of stars that are moving perpendicular to the galaxy's disk, the Acturus Stream. The star itself, is still growing closer to Earth, after it reaches its closest approach, it will begin to recede as it moves off with the rest of the stars in its stream..

.An aging star, Arcturus has already begun to burn helium in its core and it may become brighter as it approaches and if its surface continues to expand. It is destine to become a planetary nebula, with a white dwarf pulsing at the center. To find Arcturus in a sky filled with stars, observers use the adage, "Arc to Arcturus", using the "tail" of Ursa Major, or the three stars that form the handle of the dipper. The name Arcturus actually means "guardian of the bear." Following the arc of the three stars across the sky will lead you strait to Arcturus. Otherwise, just look for the first bright star you see in the Spring, taking care not to mistake a planet for one of the more distant first magnitude stars.

Even though Arcturus is well off the plane of the Milky Way, it is not an area of the sky that contains many deep sky objects. The constellation does contain a number of beautiful double stars.

--See You Under the Stars!
Astra for Astra's Almanac