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Contains:  NGC 2064, NGC 2024, NGC 2023, Horsehead nebula, IC 434, IC 430, NGC 1999, NGC 1990, M 43, NGC 1982, NGC 1977, NGC 1980, M 42, Great Nebula in Orion, NGC 1976, NGC 1975, NGC 1981, The star υOri, The star 42Ori, The star 29Ori, The star σOri, The star ηOri, The star ιOri, The star Mintaka (δOri), The star Alnitak (ζOri), The star Alnilam (εOri), Part of the constellation Orion (Ori)
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Orion in Ha - Lens Test, 


            Andreas Dietz
Orion in Ha - Lens Test

Orion in Ha - Lens Test

Technical card

Resolution: 3096x2080

Dates:Feb. 3, 2018

Frames:Baader Planetarium Ha 36mm 7nm: 61x60" (gain: 270.00) bin 1x1

Integration: 1.0 hours

Avg. Moon age: 18.03 days

Avg. Moon phase: 88.41% job: 1930437

RA center: 84.070 degrees

DEC center: -3.227 degrees

Pixel scale: 14.243 arcsec/pixel

Orientation: 90.584 degrees

Field radius: 7.377 degrees

Locations: Home Observatory, Regensburg, Bavaria, Germany

Data source: Backyard


Some weeks ago I was able to test my new Samyang 35mm F/1.2 lens due to a more or less clear night. I attached the ASI178 mono camera to the lens using my E-mount to ASI adapter. Additionally I changed some parameters of my 'Astroschelle' dovetail lens adapter for the new lens dimensions. And it worked like a charm! The only thing that caused some headaches was how to fix the 36mm Halpha filter. First I tried to insert it into the ASI's T2 mount, but unfortunately there appeared severe reflections that led to asymmetrical halos around all stars! Finally I attached it in front of the lens using some chewing gum.
So, the question was: How does the lens perform fully opened? Short answer: It's a bit behind the extraordinary Samyang 135mm F/2.0 lens. A test shot with my Sony NEX in APS-C format revealed some issues like coma... towards the corners. The IMX178 used here crops the image by a factor of 3.0, so most of these issues are no longer visible. The resolution seems to be a bit lower than of the 135mm lens. I also experienced some halos in the image center, but that may actually come from the NB filter.
For a good comparison you can have a look at my previous Orion image, taken with the 135mm Samy at equivalent exposure conditions:
By the way, the darkframes did not match perfectly, so you will see some artifacts in the background...



Andreas Dietz
License: Attribution-ShareAlike Creative Commons

Sky plot

Sky plot


Orion in Ha - Lens Test, 


            Andreas Dietz