What's Up in the Night Sky?

July 2016 - Vol. 20, No. 7

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.

Bright blue-white Vega (Lyra) shines high overhead as it "leads" the Summer Triangle across the night sky. The "Triangle" is the summer’s most prominent asterism and is made up of three stars: Vega, the brightest, Deneb (Cygnus) and Altair (Aquila). In the SW, Arcturus (Bootes) is dropping towards the horizon as Spica (Virgo) vanishes from sight below. Also look for Antares (Scorpius) low in the SW. The stars of constellations Scorpius and Sagittarius, embedded in the "Milky Way" (part of one of the spiral “arms” of our galaxy), are at their best this month. Look for another famous asterism, "the teapot" (Sagittarius). The "Great Square of Pegasus" asterism, now appears on the E horizon just before the onset of morning twilight. These are the stars of autumn that will take over when the northern summer wanes!

MERCURY is well placed for the evening twilight sky in the second half of the month that favors observers in the southern hemisphere. VENUS reappears from behind the Sun in the second half of the month. MARS sets after midnight in the constellation of Libra. JUPITER still in Leo, will be occulted by the moon for observers in the southern hemisphere. SATURN is still located in Ophiuchus. URANUS is in Pisces, favors observers in the southern hemisphere. The outer planet NEPTUNE in the constellation of Aquarius rises in the late evening.

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 or check with the U.S. Naval observatory. Unfortunately some of these events may occur during daylight hours in your area.

DATE EVENT
01 Moon at perigee.
02 Aldebaran 0.4 deg S. of the Moon occultation from Northeastern Africa, Southeastern Europe, Middle East, Southern Russia, China, and Japan.
04

Earth at aphelion.

Space probe Juno arrives at Jupiter.
07 Mercury in superior conjunction.
08

Regulus 1.8 deg N. of the Moon.

09 Jupiter .9 deg N. of Moon, occultation from Madagascar, southern Africa and eastern Antarctica..
11 Venus at perihelion.
13 Moon at apogee.
16 Mercury .6 deg N. of Venus.
26 Neptune 1.1 deg S. of the Moon, occultation observable from central & eastern North America, Greenland, Iceland, northern Scandinavia.
27 Moon at perigee.
28 S. Delta Aquarid meteor shower peak, some of these meteors will be observed during the night of the Perseid shower in August, so keep your eyes peeled for the next few weeks. This shower generates about 20 shooters per hour at peak, this year the peak occurs near the time of new moon, an excellent observing opportunity.
02 Aldebaran 0.3 deg S. of the Moon occultation from Central America, Caribbean, eastern USA, southern Europe and northern Africa.
30 Mercury 0.3 deg N. of Regulus.

Lunar Almanac for July 2016

Phases of the Moon Phase and Date(s) Best viewed before local midnight
new moon New
04
Deep Space Objects
first quarter moon 1st. Qtr
12
Planets & Moon
full moon Full
19
Moon
last quarter moon Last Qtr
26
Deep Space & Planets

Topic of the month: Hercules

Finder chart for HerculesThe constellation of Hercules commemorates the beloved hero of the myths. Hercules was a mortal who performed 12 labors, reminding Astra that there are 12 constellations on the ecliptic that are recognized as belonging to the Zodiac, or celestial zoo. On the Hercules finder chart, we can see that this celestial hunter is located between Lyra and Corona Borealis, two favorite summer constellations. The constellation is recognized by four stars that form the "Keystone", a trapezoid of stars that form the body of the figure. These stars ride high overhead in the Summer sky. This figure is thought to be kneeling. In myth, Hercules was the daughter of Zeus and a mortal woman, making him an enemy of the goddess Hera, who hated him.

The brightest star of Hercules is Ras Algethi, a red giant star that fluctuates in brightness from 3.1 mag to 3.9 or between 3rd and 4th magnitude. It is one of the largest red giant stars known, a full 600x larger than our own sun. This star is also a double star, its companion is a blue-green star that shines at 5.4 mag.

The Hercules and the 12 labors were commemorated on coins from many cultures as far back as 450 BC. Alexander the Great minted coins of Hercules, from whom he claimed he descended. Ancient Greek and Roman coins also depicted our kneeling hero and his labors. The coins with that were cited in the Bible as the thirty pieces of silver bestowed upon Judas Iscariot for the betrayal of Christ presumably were minted with images of our hero. Even the Spanish cast Hercules on their Pieces of Eight. In modern times, the 12 labors and Hercules have been minted on 2-pound coins.

Deep sky observers enjoy views of the Great Globular Star Cluster M-13, the finest such cluster in the northern hemisphere. It's magnitude is recorded as 5.7 and it has been observed on moonless nights by keen sighted observer. The Great Cluster has been measured at 23'. Another fine globular M-92 is also present in the constellation, but is overshadowed by its larger, brighter cousin. M-92 is 6.5 mag and 8' in diameter.

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

The star chart above was generated by Stellarium, a free open source planetarium program. The above image was created by Dawn Jenkins, using Stellarium and a graphic editing program to format the image for this web page. Editing was done for educational purposes only. Stellarium offers much more to amateur astronomers and is being used in planetariums and to guide telescopes in the field. 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 "What's Up?" is ©2016 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.