October

New Zealand switched to summer time, that is we put our clocks forward one hour. With the days getting shorter, solar astronomy starts looking like the better option for the months to come. The night sky is still amazing this month, with plenty of objects to look at. The fishhook of Maui sinks towards the western horizon, and with it the galactic centre, look for it to the west. Just after sunset, all the deep sky objects from Scorpius and Sagittarius are on display there. In the circumpolar region, the Small Magellanic Cloud is good to observe after sunset but all the crosses, the pots and the pans are very low on the horizon, we would look at them through a thick layer of atmosphere. Canopus is also very low, twinkling a lot.  

If you lift up your head, just after sunset, you will see Corona Australis at the beginning of the month and Grus at the end of the month. The Sun is in Virgo until October the 31st and Pisces lay on the horizon at sunset. Virgo is best seen in May, however the shadow of an obelisk at noon in October would point to Virgo on an analemma.

A bit about October

October, as the name says it, (from the Greek ôctō meaning “eight”) is the eighth month in the old calendar of Romulus c. 750 bc. This was a lunar calendar, which had 10 months, the year starting with March. Each month had 30 or 31 days and there was a period of “winter”, which consisted of approximately 50 days. October retained its name after January and February were inserted into the original Roman calendar. 

The original calendar, believed to be created by early kings Romulus and Numa Pompilius, was probably an observational lunar calendar. The first day was a kalenda, from which the name calendar derives and it signified the start of a new lunar phase, probably the new crescent Moon. The full Moon days were called the ides, and the ninth day before the ide was called none, which means more or less ninth, so the ninth day before full Moon.

Virgo

Virgo is not visible in October as we would have to stare through the blaze of the Sun at it, NEVER LOOK AT THE SUN WITH THE NAKED EYE. She was associated with the Earth-Mother and all major goddesses of antiquity: Astarte, Cybele, Isis, Innana, Ishtar, and finally, Aphrodite and Venus. Isis holds the ears of wheat in her hand that she dropped to form the Milky Way and sometimes she holds the infant-god Horus in her hand, just like Virgin Mary is holding the child Jesus (The Zodiac: Myths and Legends of the Stars, Richard Hall).

What’s the Sun up to?

In reality, the Sun does not spend an equal amount of time passing through the zodiacal constellations, for the simple reason that these constellations are different areas – patches in the sky. So technically, this month, the Sun is in Virgo where it will stay until the 1st of November, when it moves into Libra. The Sun has been in Virgo since the 17th of September. Virgo is a really long constellation to transit. 

The zodiacal constellation Virgo. The path of the Sun is marked by the yellow line. Image created with Carte du Ciel.

What’s at Zenith?

Corona Australis is at Zenith just after sunset. As the month is passing by, it’s replaced by Microscopium, which is basically a rectangle, and then Grus towards the middle of the month. If you stay late, you will be able to see these changes throughout the evening. Grus, the Crane has many double stars, and it looks like a slightly curved line. Its tail points towards the Small Magellanic Cloud, which is in the constellation of the Toucan, yet another bird. 

Fomalhaut, one of the four Royal Stars, is getting very close to Zenith too. Fomalhaut is the southernmost bright star that one can see from 45 degrees latitude North in Europe and said to show the passage south. It actually does. Fomalhaut is one of the Royal stars, along with Antares, Regulus and Aldebaran. 

The Royal stars were the guardians of the sky in approximately 3000 BCE during the time of the Ancient Persians in the area of modern-day Iran. The Persians believed that the sky was divided into four districts with each district being guarded by one of the four Royal Stars. The stars were believed to hold both good and evil power and the Persians looked upon them for guidance in scientific calculations of the sky, such as the calendar and lunar/solar cycles, and for predictions about the future.

The Milky Way, Scorpius and Orion 

The bulk of the Milky Way is on the western horizon. The Galactic centre is slowly going down, sinking behind the Sun. The Southern Cross, which is also visually in the Milky Way, dives towards the horizon, getting lower and lower each evening throughout the month, as seen after sunset. It is circumpolar so it never disappears from the Southern Sky but it means the lovely clusters and nebulae that we have enjoyed in spring and winter have long gone from being in a favourable viewing position — they now compete with the horizon.

The western horizon from Wellington, October 15 at approximately 9:00PM. Image created with Stellarium.

The patch of the Milky Way that remains in a very good position for viewing is the area around Sagittarius and Scorpius, with many globular clusters and nebulae (distant, celestial clouds) to look at. Some highlights are the bright nebulae such M16 (the Eagle Nebula), Lagoon Nebula and the very photogenic Trifid Nebula. Ptolemy’s Cluster is a great naked eye object that is visible between the two constellations.

South Circumpolar Zone

Just after sunset, the Large Magellanic Cloud  and the Southern Cross are close to the horizon where the Small Magellanic Cloud is in a good position to observe. 

The Southern Horizon from Wellington, 15 October 21:00 h, image created with Stellarium.

What’s in the night sky in October 2020

What’s in the night sky in October 2019