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  • Star diffraction patterns when using new ASI2400MC pro camera


I bought a new ZWO ASI2400MC Pro camera. My initial impressions of the camera are very positive. I think I will love using it. Well, so far I do.

This image of the Great Orion Nebula is my first-light test image using a Televue refractor. The observing site was my backyard in suburban Sydney (Bortle 6).

The aim of the image was to confirm I have the correct back focus distance and explore any idiosyncrasies of the camera before I drive a long way from the city to image faint nebulas at a dark location.

The only peculiar thing I have noticed is the unusual diffraction patterns apparent on the bright stars. Notice the dark lanes fanning outward. The diffraction pattern can be seen in the individual sub-frames. I am using a refractor with no obstructions in the optical path and I am wondering what causes the unusual diffraction patterns.

Has anyone else noticed these diffraction patterns before and do you know what causes them?

Televue NP127is Refractor working at f/7.8, focal Length 990 mm, ASI2400MC Pro Camera, Gain 0, Temperature 0 Deg. Celsius, 36 x 240-second exposures. Total integration time 2 hours 24 minutes.

fteal002

I have the same Camera and don’t have these patterns. Try Rotating the camera, if the patterns rotate as well, it is not the camera.
From there you can easily go forward testing each component in the light path.

I believe it is the optics, possibly slightly pinched. Unfortunately many refractors suffer from pinched optics if it is cold.

Cheers,

Stephan

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