Thread: Ic 342
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Old 10-01-2017, 10:04 AM
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alpal
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Quote:
Originally Posted by Geoff45 View Post
Very nice Nicola. I was also wondering about the reddish colour. Presumably obscuring dust


Off topic. No, you won't get double diffraction spikes. The orientation of the spikes in the image depends only on the orientation of your spider not the camera. Just think about the image in the image plane without the camera and suppose star A has a diffraction spike pointing directly to star B. Now bringing in the camera (in whatever orientation) is not going to change this.

Hi Geoff,
That seems correct.
I wrote it because when I was a beginner in 2011 I took
an image here:
https://www.flickr.com/photos/24719437@N03/5891049441/
& ended up with multiple diffraction spikes after stacking the data -
the bright star in the top left hand corner.
I wonder why?
Was it the before & after meridian flip that caused it
or a bad polar alignment?

cheers
Allan
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