Comet 161P/Hartley-IRAS
Captured with Seestar S30 Pro
At the end of September 2026 I noticed on the BAA Comet Section page that this periodic comet might be visible. My own software (grelf.net/ssp) confirmed that it would transit before midnight on October 1 at an altitude of just under 30 degrees from my location. So I decided to try.
60 x 30s exposures (EQ mode) showed no sign of it. So I tried 77 x 60s exposures. My alignment was good: no frames were dropped. In the resulting stack I could just about discern an extremely faint trail where my software said it should be.
I always save the individual FITS frames in the Seestar. After transferring them to my Windows laptop I used some more of my own software to restack keeping the comet fixed while the stars trailed. The result clearly showed the comet among the trails. I then used AstroWizard to smooth the background, reduce noise, and do the standard stretch. I am rather pleased with the result. The brightest stars are 90 and 96 Aqr.
I have written a more detailed account of how it was done (mainly so I could do it again when a suitable comet appears). It includes how I measured positions to determine the trail lengths, given that I could not see the comet in each frame. It is available here.
Chart from grelf/ssp
Seestar's original stack. Used full brightness/contrast stretch in Affinity. You may just be able to see the comet trace.
My reprocessed stack keeping the comet fixed.