Tonight’s sky to the west a half-hour or so after sunset. The crescent Moon is visible at the far left and in the lower left (just to the left of the tree silhouette and under the power line) you can see Venus.
What you can’t see is Comet C/2023 A3 (Tsuchinshan-ATLAS) which is lost in the Sun’s glare from our viewpoint at the moment. It’s been approaching the Sun and rising just before sunrise for the last couple of weeks. It’s apparently survived perihelion (closest approach to the Sun) without breaking up or evaporating, so there’s now a decent chance that as it approaches Earth (not that close really) that it might get bright enough to be easily seen with the naked eye after sunset. (A great summary of the key data is here. There are many other NASA and Astronomy and Sky & Telescope sites.)
This image from the “Bright Comets” app on my iPhone (highly recommended!) shows that at the time I took these pictures, the comet was below the horizon. It’s very close to the Sun from our viewpoint, the Sun had set, so had the comet. But over the next few days the comet will be moving “up” away from the Sun, so our chance to see it is coming.
(Image: Bright Comets app by Hanno Rein)
It will be a couple more days – figure next weekend or next week to start looking for it above the western horizon a half-hour or so after sunset. Closest approach is Saturday, October 12th. The comet’s position relative to the Sun and us is changing pretty quickly, but that’s a noticable change in position over days and a couple of weeks, not necessarily over minutes or hours. If you miss Saturday or it’s cloudy, look on Sunday. Or Monday. Or any evening for the next week or two after that.
Comets and their brightness are notoriously hard to predict, but this one’s been looking bright and very promising in the pre-dawn sky – Google it and you’ll find some very nice images. Let’s hope that we get lucky and next week and later in October a view like this has a bright comet rising up from the horizon with its tail stretching across most of the image.
We Love The Stars Too Fondly 