Help ! Looks like difraction spikes from my 130mm refractor

[ronk01]

Ladies and Gentlemen,
I am getting what appears to be diffraction spikes from my Orion 130 mm triplet. I do not have this issue with images taken with the same camera (ATIK 4120 EX (OSC)) through my Celestron C-11 HD with or without a HyperStar.

Can I get some suggestions from Forum Members as to what may be the cause of this issue and some suggestions on how to potentially fix the problem.
Image processing notes:
Dark, bias and color conversion done in Maxim
Star align, integration, histogram transformation, and save as Jpeg done in Pixinsight
(the results are the same if everything is done in Maxim)
Thanks in advance,
Ron K.

[msmythers]

Ron

I would guess that these are caused by the screws extending into the optical path in the scope tube. The best fix is to try to reduce the length of the screw extending into the tube without compromising what they are holding. If the screw are shiny then painting them a flat black or covering them with a non-reflective material might help. The second suggestion should be the easiest to try first. You might want to contact Orion first to see if they have any suggestions.


Mike

[Nocturnal]

Hi,

Diffraction spikes are only in your lights so calibration details don't matter. I hope you know this but since you list them.....

Diffraction spikes happen when there are straight edges in your light path. Paradoxically high end refractors are vulnerable to diffraction spikes because they can use spacers between the elements. These spacers can extend into the light cone, causing spikes. To test this you can make a round mask that is a perhaps 5mm smaller in aperture than your scope. Attach this in front of your scope and see if the spikes go away. If so then you have at least found the cause and can then decide on what to do. If the spikes remain then the edges are somewhere else and more investigation is needed.

Good luck!