|
The cross pattern you describe caught my attention. Smog. Haze will cause a halo not a cross.
The cross is most likely to be caused by -
a) spider diffraction
b) Mirror or lens pinched or under tension
Both of the above effects will be smaller, the smaller the light source. So it should be less on the Moon than planets.
The orientation of the cross might tell you something. For example if you have a newtonian and the cross lines up with its 4 spider vanes and has the same orientation as those vanes then that might be the culprit. If it lines up with tensioning screws in an optical cell etc
Joe
|