Quote:
Originally Posted by obrads
Hey everyone  , i have had two imaging nights so far with my ASI1600mm, the first night i had some focuser tilt issues so i fixed that by tightening things up and then last night when i went shooting i noticed i had these strang ghost stars in my images. any idea what it might be and what steps i should take to try eliminate the issue? 
im using a saxon ed 100, 0.85x ed 100 focal reducer and flatterer, ASI1600mm with filter wheel and the zwo off axis guider with a QHY5L 11. thanks guys |
The edges of the OAG will (may) cause some noticeable diffraction and reflection. Who knows how much? It would depend on alignment & other conditions....
There are 8 spikes (diffraction spikes) and fuzz around some of the brighter stars? You are using a refractor so I wouldn't have expected any diffraction spikes in the image, so look for some sharp edge/s in the optical path or near the edge of the path. Can you try to image WITH the OAG in place and WITHOUT the OAG in place? That might be something to rule out. Any obstruction (including an aperture stop in a lens) can cause such things, although the number of spikes and the look of the diffraction will vary.
Best
JA