Session Data

• Date:  23/03/2020  
• Time:  20:53 – 23:22 UT
• Seeing: II Mostly Stable, 
• Transparency: Mostly Clear, 
• Temp:5.5C, Air Pressure: 1023mb, 
• Humidity: 85%, Dew Point: 3.5C, 
• Wind Speed: 8.5mph

Scope: TMB 80mm APO Refractor at f/6  Camera: ZWO ASI 1600MM Pro,  No filter, Dark subtracted, No Flats.

NGC 3031-M81

A total of 73 x 60sec light frames which have been dark subtracted. I wasn’t really worried how this turned out as this session was more of a test of how PHD was performing. Not having used PHD before, I was generally playing around with the various settings to see how they would affect the guiding error rates.

This actually came out quite well. Below is an closer crop

One thing that is obvious though is that at f/6 this field is not flat. I do have a Televue 0.8 focal reducer and flattener that I will try next time and see how that helps the shape of the stars at the edges.