By Prashant Naik
The chart above shows the night sky over Shillong during the month of September 2013 at 8.00 p.m. Shillong being at 25.5o N,latitude we see mostly northern constellations.
The E-W line shows the celestial equator and the line cutting it shows the zodiac line or the sun’s apparent path.
The capital letters indicate the name of constellations and the other letters indicate the prominent stars.
Planet Saturn is visible only near the western horizon during the early part in the night (Planet Uranus,Pluto and Neptune would be visible through very powerful telescope only.)
The prominent constellations visible are Aquila,Cygnus,Lyra,(the famous summer triangle)Pegasus, Andromeda.,Aries, Draco, Bootes,. Cassiopea,Cepheus,Ursa Major, Ursa Minor, Libra, Virgo, Aquarius, Pisces,Capricornus, Sagittarius, and Scorpius.
The constellation of the month is Pegasus.The constellation Pegasus represents the white, winged horse of Greek mythology.
This beautiful figure can be seen high in the sky starting near the end of summer and continuing through autumn in the Northern Hemisphere. When looking at the image, it is difficult to see the figure as a horse. That is because the constellation is actually upside-down!
Imagine it flipped over, and you can see what could be the neck and head of a horse and two legs sticking out from the famous “Square of Pegasus”.
This square represents the front half of the horse’s body. Mythologists are still not sure what happened to the other half of the constellation, but some believe a part of Pegasus was used to create the image of Aries the Ram.
The square is very easy to find in the night sky. The neck and legs of the horse shine brightly on clear nights.
The story behind Pegasus begins with the battle between Perseus and Medusa.
When Perseus severed Medusa’s head, drops of blood fell into the sea.
They mixed with sea foam, and Pegasus was born. The white sea foam gave the horse his brilliant color. Pegasus became friends with the warrior, Bellerophon.
One day, Bellerophon tried to ride Pegasus to Mount Olympus.
This angered Zeus so much that he sent a gadfly to bite Pegasus.
When the horse was stung, Bellerophon fell to the Earth. Pegasus made it to the home of the gods, where he still remains.
Pegasus can be recognized by the prominent square formed by three member stars (â, á and ã) and á, Alpheratz, in the neighbouring constellation of Andromeda.
Alpheratz lies on the very border of the two designated areas.
The three corners of the square of Pegasus are all above mag 3 and are good observational objects.
Star â, Scheat, is a large M2 variable red giant (absolute mag – 1ÿ5) at a distance of 210 light years and may range between 2ÿ4 and 2ÿ7.
Star á, Markab, is a white B9 of mag 2ÿ5 and ã is a mag 2ÿ84, B2 type (absolute mag – 3ÿ4) at distances of 110 and 570 light years respectively. Northwest of â lies ç, Matar, a mag 2ÿ95, G8 star.
Star å, Enif, is a mag 2ÿ4, K2 type star with a mag 11ÿ2 companion. Enif is nearly 520 light years away and has an absolute mag of – 4ÿ6. Northwest of å lies M15, a 6th magnitude globular cluster.
Pegasus is home to the globular cluster, M15. This is a great object to view with a telescope because it is one of the brightest in the sky. M15 lies slightly northwest of the head, which is made of the star, Enif.
Approximately one dozen galaxies are within Pegasus, the brightest one being NGC 7331. It is located just north of the “knees” of Pegasus.