What's Up in the Night Sky?

May 2015 - Vol. 19, No. 5

Astra's Star Gate

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.

As May brings the lengthening days, the hours of nightly observation decrease as well, it is always with a bit of sadness that we say good-bye to the Winter and Spring constellations, Gemini, Leo, and Virgo. The early evening presence of Arcturus, the second brightest star in the northern sky, reminds us that the bright star clouds of the Milky Way will soon be brightening up those dark evenings when the Moon is small enough to allow us to truly enjoy those galactic treasures. As the evening turns to morning, the bright stars of the summer triangle follow until just before sunrise, the Milky Way is at the zenith, high overhead. Long twilight hours come to the northern hemisphere.

MERCURY is best seen from the northern hemisphere through the 21st, the most favorable apparition of 2015. VENUS rides high in the evening sky. JUPITER is in the constellation of Cancer, setting after midnight. MARS is lost in the Sun and will reappear in the morning sky in August. SATURN is visible all night and will be at opposition on the 23rd. URANUS rises in morning sky later this month.

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.

04 Uranus 0.2 deg N. of Moon, occultation from Central S. America, W. and Central Africa
05 Saturn 2 deg S. of Moon.
06 Eta Aquarid meteor shower, up to 60 per hour may be seen at the zenith from a dark site. Best observing is after midnight, watch for meteors on Wednesday morning.
07 Mercury greatest elongation E.
10 Venus greatest heliocentric latitude N. Our nearby neighbor puts on its best show for the Northern hemisphere, over -4 magnitude!
15 Moon at perigee. Uranus 0.2 deg N. of Moon, occultation from Central S. America, W. and Central Africa.
19 Mercury 6 deg N. of Moon.
21 Venus 8 deg N. of Moon.
23 Saturn at opposition. The ring plane will be tilted 24.4 deg. toward Earth.
24 Jupiter 5 deg N. of Moon.
26 Moon at apogee.
30 Mercury at inferior conjunction

Lunar Almanac for May 2015

Phases of the Moon Phase and Date(s) Best viewed before local midnight
new moon New
Deep Space Objects
first quarter moon 1st. Qtr
Planets & Moon
full moon Full
last quarter moon Last Qtr
Deep Space & Planets

Topic of the month: The Summer Triangle, Lyra

The Summer Triangle is an asterism, a group of stars that are not a constellation, but have earned a popular nickname. It is formed of three bright stars that dominant the summer sky, Vega, Deneb, and Altair, each the brightest member of its constellation. These are Lyra, Cygnus, and Altair respectively. This year, the night sky will pay tribute to the three constellations that are part of the Summer Triangle. This month features Lyra, home of the well known bright star, Vega.

The constellation Lyra is small, but prominent in the Summer Sky. The blue giant Vega is located in the northern sky, and was at one time a pole star about 14,000 years ago and will be again someday. Vega was one of the first stars to be photographed and early infrared studies showed that it was surrounded by a disk of dust. It far outshines the Beta and Gamma stars of the constellation, Epsilon Lyrae is a fine double star, easily resolved in small instruments. It is sometime called the Double double, because each of the bright components is a double star itself.

Lyra is also home to a fabulous deep sky object, a planetary nebula that is commonly known as the Ring Nebula. In a good telescope it will look like a smoke ring, but it is 3100 light years away. It takes a larger amateur instrument to see the central star that is best revealed in a photograph.


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

The star chart above was generated by Stellarium, a free open source planetarium program. This image was created by Dawn Jenkins, using Stellarium and a graphic editing program to highlight M44 and to format the image for this web page. Stellarium offers much to amateur astronomers and is being used in planetariums. Simple charts like the one above can be used on the internet for non-profit, illustration purposes. Proper credit is due of course! Thank you to the makers of this fine program from Astra's Star Gate.

This installment of "Whats Up?" is ©2015 by Dawn Jenkins for Astra's Stargate. View Ron Leeseburg's Farewell Issue for information on where to find information such as is presented in this almanac.