I made a small (243 kB) movie of 177P Barnard traversing 5 arc minutes of sky. In all of my movies I usually see a bit of jitter from frame-to-frame. I finally think I know the source of the jitter– I think it’s seeing. My seeing for the movie was poor, about Pickering 3 or 4 arc seconds or so FWHM. This is typical for the Midwest USA.
If you look at the movie you will see the PSF of stars changing from one frame to the next. It is easiest to see on the faintest stars. The image scale is 2.5 arc seconds per pixel, re-sampled from 5.0 arc seconds per pixel in the original 2x2 binning.
Each frame is a four minute exposure, and I’d have though that seeing effects would average out during this long a period, but I still think seeing is the predominant effect. I’d appreciate comments from others on the root cause.
Movie and other info at
http://home.att.net/~dpersyk/new.htm
Thank you for visiting my site.
Clear skies,
Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL
If you look at the movie you will see the PSF of stars changing from one frame to the next. It is easiest to see on the faintest stars. The image scale is 2.5 arc seconds per pixel, re-sampled from 5.0 arc seconds per pixel in the original 2x2 binning.
Each frame is a four minute exposure, and I’d have though that seeing effects would average out during this long a period, but I still think seeing is the predominant effect. I’d appreciate comments from others on the root cause.
Movie and other info at
http://home.att.net/~dpersyk/new.htm
Thank you for visiting my site.
Clear skies,
Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL
