Session Data

  • Date:  06/08/2023
  • Time:  22:25 – 23:11 UT
  • Seeing: III. OK – Moderate
  • Transparency: II. Clear with some cloud
  • Temp: 12.3C,
  • Air Pressure: 1025mb, 
  • Humidity: 95%, 
  • Dew Point: 11.7C, 
  • Wind Speed: 4mph

Scope: Altair 250mm RC f/5.3  Camera: ZWO ASI 183MM Pro,  No filter, Dark subtracted and Flat fielded.

Session Notes: Just a quick look at C/2023 E1 before going on to start imaging M17 for the first time.

I’m not sure what it is about EAA, but the visual observers scorn it because it’s imaging and the imagers say it’s not proper imaging. They may both be right, but over the last year many more astronomers seems to be doing their astronomy this way. Plug EAA into Youtube and you will find may tens of videos showing users how they do it.

OK. It’s not visual astronomy. What we look at on the screen even after one single frame bears very little resemblance to what you would see through and eyepiece, but then you are not freezing your bollocks off in the cold and getting backache. I do however have the advantage that if I run my subs for long enough, I can end up with a reasonably decent image afterwards if I process those subs in a normal manner, so that’s a plus.

This is a comet aligned stack of of 30 x 15 second subs. You get a much better sense of its size and shape this way, although estimating the coma size is tricky, I came up with a diameter of 1.5 arc minutes. Skytools shows there should be an extensive tail running towards the South, but there is no evidence of it here.

This is a star aligned stack, which shows the Comets track during all 30 exposures.

What really blew me away is how accurate the position of the comet was when I observed it. Above is a CCD view of the comets position at the time of the first frame as calculated in SKytools 4 Imaging. I didn’t log NINA calculation for frame rotation, so have manually adjusted it as best I can, but it’s close enough to show how accurate the orbital element calculations are.

Anyway, I enjoyed the 40 odd minutes watching the image build up in Sharpcap live stack, while waiting for the conditions to image M17 improve.