A bright comet for October beckons

Sky-watchers could be in for a real treat this month as a bright comet becomes well placed for viewing from Ireland, writes John Flannery.

Designated C/2023 A3 (Tsuchinshan-ATLAS), the first-time visitor to the inner solar system put on a great show recently in the morning sky for more southerly based observers.

A3 passed between the Earth and the sun on October 9 and now moves into our evening sky. Initial sightings from here should come last weekend, with the comet low at first above the western skyline as twilight fades.

Over the next couple of weeks, the comet appears higher each evening and will be easier to see, but we have to contend with full moon on October 17, whose light will interfere somewhat. However, the moon rises a little later each evening thereafter and shouldnot pose so much of a problem.

The bright head of the comet will be easy to pick out, along with a narrow tail several moon-widths long, but binoculars - and a dark site away from lights - will allow you trace the dusty tail further. A3 ought to be a bit brighter than comet Neowise that was seen in July 2020.

A short time exposure with a tripod mounted camera will give pleasing results, while propping your smart phone against something will allow you to use its longest time exposure in night mode - using the self-timer function will also prevent smearing from vibrations when you press the shutter button. Online searches will return detailed guides on observing A3.

The comet slowly fades towards the end of the month as it retreats into deep space and will likely drop below naked-eye visibility by the end of October. Over the next couple of weeks though, we look forward to a fine performance on the evening sky stage.