Comet Tsuchinshan-ATLAS C/2023 A3 will be visible above the western horizon from October 11 on. It will be very close to the sun, following sunset closely enough that it will probably be swamped by the bright sky. But each night it will set father behind the sun (along the arc the sun has made in the sky) and the sky will be darker before it sets. It will also be moving away from the sun in space so it will be getting dimmer and more distant from Earth. There will also be some moonlight – October 17 is the full moon, but on subsequent nights it will rise about 40 minutes later each night.
There are predictions it may be bright enough to be visible in daylight, so that will help. It will be small and dim by daylight photography standards, but I expect good results with a telephoto lens and a sturdy tripod and remote release. The focal length will depend on how bright the tail is, but moderate telephotos got nice shots of Neowise in 2020.
I’ll also use my tracked astrophotography rig. That’s how I got the last two, last March and in 2022. The tail on Pons-Brooks changed day to day and this was one of the better days, so I’ll shoot as many days as I can. They are all quite different.
Shooting with a DSLR it pays to keep the ISO as low as you can within your tolerance for star trailing. And you can see from the astro rig shots (a 400mm refractor) why I hate stars with regular lenses.
Diane - STUNNING shots! Thanks forthe information; we may have a chance at seeing the comet if the coastal fog lays low a few days.
I’m really loooking forward to your images.
In the next few days it will be visible in the eastern sky before sunrise. The best day for being highest before it gets too light is Sept 28, but several days on either side could be good too. It will rise ESE about an hour before sunrise, and as it gets higher the sky will get lighter, but there should be a short time you can see and photograph it. You will want a very low horizon to the east – very low!
I may have one morning without fog here, from a nearby ridge. Maybe…
Just experiment to find a decent exposure from the back of the camera, or if you have a live histogram. Zoom in to focus if you can see stars – the lens infinity mark won’t be good enough. You can shoot a set and align the stars in Starry Landscape Stacker (Mac) or Sequator (PC) to reduce noise, but the comet will move slightly against the stars. Stacking for NR is hardly worth it these days with the current NR software. I’ll be up at 5 am to shoot from a nearby hill starting at 6 am until it’s lost in the pre-sunrise light. I may try several different exposures but not sure they will combine well. No harm trying – electrons are cheap. I won’t have a chance to set up the tracker for the morning shoots – will hope for clear skies in 2 weeks where I can track it from the house in the evening twilight with the astro rig and process properly in PixInsight.
