aka NGC 869 + NGC 884
William Optics ZenithStar 71 Achromat
Atik 314E Mono CCD
GSO Wratten #12
Optolong Red and Green
W12: 26x60s
R: 70x60s
G: 35x60s
Color Combine:
W12 => L
67% R => R
33% R + 33% G => G
67% G => B
Post-process color calibration not needed due to balanced frame count (planned ahead of time).
Calculated SNR 87 of a magnitude 16.0 star at 3.0" FWHM seeing.
Brian
Perseus Double Cluster
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Please upload large images to photo sharing sites (flickr, etc) rather than trying to upload them as forum attachments.
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Please upload large images to photo sharing sites (flickr, etc) rather than trying to upload them as forum attachments.
Please share the equipment used and if possible camera settings to help others.
Perseus Double Cluster
Last edited by oopfan on Thu Nov 19, 2020 1:33 pm, edited 1 time in total.
Re: Persius Double Cluster
Very good Brian.
Dave
Dave
Re: Persius Double Cluster
Thanks, Dave.
Something I noticed: The diffraction pattern depends on the filter as can be seen in the attachment. I am certain that this is due to the 2mm thickness of the Newtonian Mask's vanes. Long wavelengths (red) diffract more than short wavelengths (green), so red light does a better job of merging the two edges of a vane into what looks like a single diffraction spike. I'll experiment with a different thickness. At the time I designed the mask I was concerned that a thin vane would tear as I lifted it from the plate.
Brian
Something I noticed: The diffraction pattern depends on the filter as can be seen in the attachment. I am certain that this is due to the 2mm thickness of the Newtonian Mask's vanes. Long wavelengths (red) diffract more than short wavelengths (green), so red light does a better job of merging the two edges of a vane into what looks like a single diffraction spike. I'll experiment with a different thickness. At the time I designed the mask I was concerned that a thin vane would tear as I lifted it from the plate.
Brian
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Re: Perseus Double Cluster
Now that is a stunning image! You need to print that one out and hang it up!!
Bruce
Bruce
Re: Perseus Double Cluster
Thanks, Bruce, but you know, it never fails, every step forward leads to more head scratching and then refinement. We, I mean "I", never seem to be happy with what I've accomplished. I thank you for your kind words!
Brian
Brian
Re: Perseus Double Cluster
Bruce,
I went back and scrutinized my frames and discovered that I was badly out-of-focus in G and W12. Red was excellent. I am to blame. I was racing against the meridian. I usually spend more time when focusing but I was rushed. As it is I had to cut short my W12 run when my scope banged up against the mount. Also, I looked at the stars in my M34 data from last week. The diffraction pattern in G and W12 was just as good as R. So, that is the bottom line: focus.
Brian
I went back and scrutinized my frames and discovered that I was badly out-of-focus in G and W12. Red was excellent. I am to blame. I was racing against the meridian. I usually spend more time when focusing but I was rushed. As it is I had to cut short my W12 run when my scope banged up against the mount. Also, I looked at the stars in my M34 data from last week. The diffraction pattern in G and W12 was just as good as R. So, that is the bottom line: focus.
Brian
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- Posts: 408
- Joined: Fri Apr 28, 2017 1:28 pm
- Location: Central Florida
- Contact:
Re: Perseus Double Cluster
Thanks for the update, Brian. Well, we have all rushed at times and failed to focus or especially refocus as needed. I am guilty of that for sure. Glad you sorted it out.