By Prashant. Naik
The chart alongside shows the night sky over Shillong during the month of September 2019 at 8 pm.
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 Jupiter would be visible towards the western sky.
Planets Neptune and Pluto will be visible through powerful telescope only.
The prominent constellations visible are Aquila, Cygnus,Lyra (famous summer triangle), Pegasus, Andromeda. Pisces, Bootes Draco, Cassiopea, Cepheus, Ursa Minor, Pisces, Aquarius, Capricornus, Sagittarius, Scorpius, Opiuchus and Libra.
The constellation of the month is Capricornus Despite its faintness, Capricornus has one of the oldest mythological associations, having been consistently represented as a hybrid of a goat and a fish since the Middle Bronze Age, first attested in depictions on boundary stones and explicitly recorded in the Babylonian star catalogues as “The Goat-Fish” before 1000 BC.
The constellation was a symbol of Ea and in the Early Bronze Age marked the winter solstice.
Due to the precession of the equinoxes the December solstice no longer takes place while the sun is in the constellation Capricornus, but the astrological sign called Capricorn begins with the solstice.
The sun’s most southerly position, which is attained at the northern hemisphere’s winter solstice, is now called the Tropic of Capricorn, (23.5 degrees latitude) a term which also applies to the line on earth where the sun is directly overhead at noon on that solstice.
The planet Neptune was discovered in this constellation by German astronomer Johann Galle, near Deneb Algedi (ä Capricorni) on September 23, 1846, which is reasonable as Capricornus can be seen best at 4am in September.
This constellation is sometimes identified as Amalthea, the goat that suckled the infant Zeus after his mother Rhea saved him from being devoured by his father Cronos in Greek mythology. The goat’s broken horn was transformed into the cornucopia or horn of plenty. Some ancient sources claim that this derives from the sun “taking nourishment” while in the constellation, in preparation for its climb back northward.]
However, the constellation is more often depicted as a goat with a fish’s tail. One myth says that when the goat-god Pan was attacked by the monster Typhon, he dove into the Nile; the parts above the water remained a goat, but those under the water transformed into a fish.
In Sumer, the constellation was associated with the god Enki (Babylonian Ea), who brought culture out of the sea to humankind.
The main star, ä, Deneb Algedi, is a mag 2ÿ95-2ÿ88 variable A6 type about 50 light years distant.
Two naked-eye doubles are of interest. Á, Giedi Prima, is of mag 4ÿ2 with a binary companion of mag 9, and Giedi Secunda, is mag 3ÿ6 with a binary companion of mag 11.
The second pair, â, Dabih, is very close with mags 3ÿ3 and 6. A globular cluster, M30, lies below Deneb Algedi.
Full moon will be on September 14 and new moon on 28. Equinox where the the day and night are of equal time will be on 23.