See 2-day-old crescent Moon occult naked-eye star from western British Isles

Observers in the west of the UK and the Republic of Ireland are best placed to see the occultation of 4th magnitude star Theta (θ) Aquarii tonight shortly after 7:15 pm GMT — an event visible in binoculars. AN graphic by Ade Ashford
Observers in the west of the UK and the Republic of Ireland are best placed to see the occultation of 4th magnitude star Theta (θ) Aquarii by the crescent Moon shortly after 7:15 pm GMT tonight — an event visible in binoculars. AN graphic by Ade Ashford
Shortly after 7:15 pm GMT on Thursday, 22nd January, observers in the west of the British Isles are best placed to see 4th magnitude star Theta (θ) Aquarii — commonly known as Ancha — slip behind the dark limb of a 2-day-old, 7% illuminated crescent Moon.

The precise time of the occultation will vary depending on your location (it occurs at 7:19 pm from London, 7:17 pm from Edinburgh), but the important fact to remember is that the further west you are, the better your chances of seeing it as the Moon and star will be very low to the west-southwest horizon — too low, realistically, to be seen from eastern England.

Since the Moon will approach Ancha unilluminated hemisphere first, the star will be seen to abruptly disappear at the otherwise darkened lunar hemisphere which will be glowing due to earthshine as seen in binoculars and telescopes. To be sure you don’t miss out, be in place and watching intently from 7:15 pm.

Telescope owners will undoubtedly get the best view, but observers with low power binoculars (7×50, 8×40, etc.) will have the added bonus of encompassing the Moon, Ancha and planets Neptune and Mars in the same field of view! Clear skies to all making the attempt.