First Light WOGT81

[MikeCM]

The clouds cleared briefly tonight and I was able to try out my WO GT81 with focal reducer for first time since getting scope in Dec. I took a 25s unguided shot of M45 but as you can see in the attached picture the stars have some wedges out of them in a consistent pattern.Most noticeable on zooming in.

Is this typical for this scope ? I do not see anything protruding into the optical train or defect of glass.

[Skyline]

Are you sure it is not something intruding into the light path, have you tried using it without the reducer.

[cjdawson]

There is defiantly something causing a diffraction.   I've just done a quick search and found this similar thread on another forum

http://www.cloudynights.com/topic/506480-help-william-optics-gt81-diffraction-obstruction-pinched-optics/

 

So you don't have to read everything there are a few things to try out.

Orient the camera differently on the telescope and see if the artifacts move.   If so, try with another camera just to be sure.

If this is the case, then we know for sure that it's something in the telescope itself rather than the camera.  Two different camera won't have the same issue.  And by rotating the camera on the scope you'll be able to see that it's consistent with the orientation of the scope - again, doubly confirming it's the scope rather than the camera.

 

There are other things suggested on the linked thread which mean loosing the scope.  I don't know that scope well enough to know if it's a good/bad idea, or not.