Observation by Martin Lewis: Mars RGB 10th Dec 2022
Uploaded by
Martin Lewis
Observer
Martin Lewis
Observed
2022 Dec 10 - 00:08
Uploaded
2022 Dec 12 - 10:54
Objects
Mars
Equipment
- 444mm Dobsonian
- Uranus-C camera and L filter
Location
St Albans, UK
Target name
Mars
Title
Mars RGB 10th Dec 2022
About this image
The 'boring' side of Mars looking not so boring in superb seeing on the night of 9th/10th December. Test of three camera at f29 was carried out during the session. Lovely structure in Mare Sirenium.
-my new 2.9um pixelled Uranus-C which would be slightly oversampled
-my trusty 3.75um pixelled ASI224MC which should be correctly sampled for a colour camera
-my newish 5.8um pixelled ASI482MC which should be slightly undersampled in good condition
All three gave good results but the undersampling of the last camera showed. Got similar results with the first two camera but took more videos with the Uranus-C so ended up finishing the processing, includinjg Winjupos derotate, with that camera.
Martin
Files associated with this observation
Like this image
Comments
Martin
Very interesting to see the comparison of the three cameras. Did you mean ASI482MC for the third camera? I am still using my 482MC at the moment but am awaiting delivery of a Uranus-C and will then be looking for similar comparisons.
Peter
Well spotted Peter, yes 482 not 582 (now corrected).
Will post comparison for best single videos for each in next few days. At f29 and 5.8um pixels I think I am undersampling. What f-ratio are you using your camera at?
Usual rule of thumb for colour cameras to satisfy Nyquist is 5x to 7x pixel size in microns. For ASI482MC with 5.8um pixels and f29 we get 5x but in very good conditions which these were I should have used 7x. For ASI224MC with 3.75um pixels we get 7.7x so better.
Martin
Martin
That comparison will be helpful. Nyquist at (7x5.86)/10 gives me almost exactly 4 and suits using my 14inch with the 4x PowerMate almost spot on. So hopefully my sampling with the 482 is fine.
Peter
Copyright of all images and other observations submitted to the BAA remains with the owner of the work.
Reproduction of work by third parties is expressly forbidden without the consent of the copyright
holder. By submitting images to this online gallery, you grant the BAA permission to reproduce them in
any
of our publications.
