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Another question,sorry...camera tilt
I have been taking pictures with a Canon 60DA with an Orion thin off axis guider between the camera and the 'scope, prime focus Melon 210.
When I combined images from three consecutive nights I saw double diffraction spikes on the same side of bright starts,the thumbnail "all 28".
These double spikes are present in all the subs, just minimised by focusing.
After pondering for a while I removed the off axis guider , used a Takahashi EOS adapter and used a 200mm guide scope (yes, too short for the Mewlon but its what I have available). I focused carefully and the double spikes were not present , thumbnail "first".
Frame 12 ,thumbnail last, (8 minute subs) shows the spikes returned. I guess due to the scope cooling and shrinking thus throwing the focus out.
If the camera was flat I would expect to see all spikes double, so I conclude that the camera is tilted.
A double barrel question,why does camera tilt only produce double spikes on one side, and, how do you find where to shim to flatten the camera.
Chris
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