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August 17-18, 2018: NGC7000 to Sadr with Zeiss 85mm


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This was a first experiment with my old Carl Zeiss Planar 85mm F/1.4 (Contax mount) on my modded Canon EOS 550D. I stopped the lens down to F/2, and took just 31 lights at 30s each, at ISO 400. Combined with 30 flats and 15 darks, I am quite pleased with this first result. F/2.8 might be better, however.

NGC7000-85-2.thumb.jpg.6f75f84d84292f70651097ec2343e5ac.jpg

More data would also be a good idea, as ever, but for just 930s of data, the result is pretty neat

 

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10 minutes ago, happy-kat said:

Looks great. Did you focus on a third intersection? If not why not try that before stopping down further.

The thirds rule is mainly to counter field curvature, which is extremely small in the Zeiss Planar lens design (hence the name), especially one which has been designed for a 1.6x larger field. What I am seeing looks more like coma, so stopping down is probably best. I did actually focus on a star roughly at the one third intersection, but simply because that was conveniently placed

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