This month the nights become longer and we move towards unsettled weather. The autumn constellations are starting to show. Ursa Major, or the Plough, can be found low in the North. The ‘W’ of Cassiopeia is not far from the overhead point. Also on view this month we have, Aquarius the water carrier, Cetus the sea monster, Capricorns the sea goat, Pices the fishes, Piscis Austrinus the southern fish and Delphinus the Dolphin.
The summer triangle of Altair, Deneb and Vega remains high up. The southern sky is dominated by the Square of Pegasus. The bright star Capella in the constellation of Auriga the Charioteer is becoming more noticeable in the east. It will be overhead in winter evenings.
Although the four stars that form the Square of Pegasus are not the brightest, once found they will be easily recognised again. It is always an interesting project to count how many stars you can see within the square; you might be surprised by the result.
If you use the two right hand stars of the square and draw a line to the south you will reach a bright star very low in the sky. This star is Fomalhaut, in the constellation of Piscis Austrinus.
Venus lies low in the west after sunset. Shining at a brilliant magnitude of –4.1. It sets around8.30pm. On 5th of the month Venus passes over Spica.
To the lower right of Venus you may spot Mercury magnitude 0.0 deep in the twilight glow. Mercury reaches maximum separation from the Sun on 14th September.
The two largest planets; both lying in Capricornus are livening up the rather dull starry southern sky. Bright Jupiter at magnitude –2.8 sets around 4am, while Saturn just to the right glows at a dull magnitude of +0.4 and falls below the horizon about 2.30am.
Neptune, located in Aquarius, is above the horizon all night long. At magnitude +7.8 it is best observed through binoculars or a telescope. Neptune is at its closest to Earth on 14th of the month at 4326 million kilometres away.
Distant Uranus lies in Aries and is just visible to the naked eye at magnitude +5.7. It rises into view from 9pm.
Mars is o close to the Sun to be visible this month
Special Events :-
9th September – A thin crescent Moon lies to the right of Venus, with Mercury very low on the horizon.
10th September – Venus forms a stunning duo with the crescent Moon.
16th September – The Moon passes below Saturn, with Jupiter to the left.
17th September – Jupiter is to the upper left of the Moon, while fainter Saturn lies to its upper right.
18th September – The Moon is to the left of bright Jupiter.
23rd September – The Autumn Equinox, and the nights slowly become longer for the next three months.
25th September – The Moon passes under the Pleiades.
26th September – Aldebaran and the Hyades lie to the right of the Moon.
The phases of the Moon for September are:-
New Moon 7th
First Quarter 13th
Full Moon 21st
Last Quarter 29th