night sky

The October 2023 Night Sky

Welcome to the October night sky. Now that the autumnal equinox in the northern hemisphere has passed, the nights will become noticeably longer, and it will become darker much earlier than in the previous month.

And at the end of October, on the 29th, the clocks go back and then we are well into the darkness of autumn.

This month has four meteor showers but only two of them are reasonable ones, worth looking out for. The first is the Draconids on the 8th – this is the dust left over from the comet Giacobini Zimmer discovered in 1900. The second is the Orionids from the tail of Halley’s comet with its peak on the night of the 20th.

The new Moon of the 14th will be creating a solar eclipse. The Moon will pass directly in front of the Sun, but, as the Moon is close to perigee, it will fail to cover the disc of the Sun completely – this is called an annular solar eclipse, the outer rim of the Sun will still be visible, and its brightness will obscure the solar corona.

This eclipse will be visible in a narrow strip of land passing down western north America through central America and ending up in northeastern Brazil.

Two weeks after this eclipse, on the evening of the 28th, we will have a full Moon but, because of the close alignment of the Moon’s orbit with the ecliptic that caused the annular eclipse, we will have a penumbral lunar eclipse – that is when the full Moon enters partially into the shadow of the Earth. This will occur at moonrise.

The brilliant planet Venus is at its greatest western elongation from the Sun on the 24th when it will be seen early in the morning high in the eastern sky, several hours before sunrise.

The gas giant planet Jupiter is in the constellation of Aries and will be visible all night as it comes to opposition very early in November. Through a small telescope or powerful binoculars, the four Galilean Moons discovered in the early 1600s will be easily visible.

In the constellation of Leo at a distance of 120 light years, an exoplanet nine times the mass of the Earth, designated K2-18b, has been examined by scientists using the James Webb Space Telescope, and an international team has just found evidence for carbon dioxide and methane on the exoplanet. It has also been found to have in its atmosphere dimethyl-sulphide; this chemical is produced primarily by algae, and it is responsible on Earth for the smell of the oceans.

It is entirely possible that this exoplanet, which is in the habitable zone of its star, has oceans with some form of organic life, probably microorganisms. Our life on Earth started in the oceans and possibly this exoplanet is doing the same thing.

The Moon is at last quarter on the 6th, new on the 14th, first quarter on the 22nd and full on October 28.

By Clive Jackson
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Clive Jackson is the director of the Camera Obscura – Tavira EYE attraction, located near the Castle of Tavira. Specialising in education and public outreach.
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To see the October Sky Map click on the pdf link below

2023-10 October nightsky