Full darkness starts at 20:47 at the beginning of October, lasting until 05:14 the next day. By the end of the month, we can welcome the dark skies from 18:39 – as the clocks have come back an hour – lasting until 05:10. The month of October definitely marks the start of the high season for the keen astrophotographer!
Cassiopeia is almost overhead in the late evening, as the Summer Triangle of Vega, Altair and finally Deneb start to slide away over the western horizon. The Andromeda Galaxy, M31, is a fine target nearby, just discernible with a fully dark-adapted naked eye, and very distinctive in binoculars or a small telescope. I shall try and improve on my effort from last year, now that my mount’s tracking has been sorted out.
Towards the south, Taurus is moving across the sky by late evening, with the bright star Aldebaran in the magnificent cluster of the The Hyades. Just above, the smaller but very distinctive cluster of The Pleiades is always a good test of eyesight: how many stars can you count unaided?
Planets in alignment
Early October – still just in time for the late uploading of this page (sorry!) – sees several planets in alignment in the early hours just before dawn. Most spectacular will be the display on the 9th and 10th. On the morning of the 9th, Jupiter, Mars and Venus will be lined up above the eastern horizon at about 05:30 – with a crescent Moon in between Mars and Venus for good measure. An hour later, Mercury will also rise to make a line of four planets.
On the morning of the 10th, the crescent Moon will be below Jupiter and only 6% of its surface will be illuminated – a very thin crescent in the same four-planet alignment.
Orionids Meteor Shower
This year the Orionids will peak from the 21st to the 23rd, and will be Moon-free after midnight. Not normally as prolific as the Perseids, the Orionids are nevertheless worth looking out for, as they often display brighter, slower meteor trails. They emanate from the region above Betelgeuse, the bright yellow star of Orion’s eastern shoulder.
Just mentioning that Orion will be in the sky means that the long winter nights are definitely on the way!
These are just my highlights. As always, for a full guide to the night sky this month, I recommend Ian Morison’s excellent page on the Jodrell Bank website.