Celestial hemisphere:  Northern  ·  Constellation: Ursa Major (UMa)  ·  Contains:  M 101  ·  NGC 5457  ·  NGC 5461  ·  NGC 5473  ·  NGC 5474  ·  NGC 5477
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M101 with 400mm & 2X teleconverter, TStew
M101 with 400mm & 2X teleconverter
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M101 with 400mm & 2X teleconverter

Getting plate-solving status, please wait...
M101 with 400mm & 2X teleconverter, TStew
M101 with 400mm & 2X teleconverter
Powered byPixInsight

M101 with 400mm & 2X teleconverter

Equipment

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Acquisition details

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Description

I decided to go back to my trusty 400mm f5.6 lens. This lens has much smaller aperture than my big 500mm Canon (71mm vs 125mm) but has produced images with less distortion and aberrations. I imaged it with the bare lens which I will likely reprocess and upload later but for this session I decided to try it with a 2X vIII Canon extender. This makes the lens behave as 800mm f/11, and I further stopped it down to f/13. I knew I'd need a lot of imaging time with that slow of a lens, so I shot across 3 nights, about 12 hours before throwing out subs. Unfortunately that included much of the imaging time with the moon out, up to half or so lit. I had to back off exposure time a bit with the moonlit skies, so this was my first session with different exposures (some 180, 240, and 300 sec subs) which I just stacked all together.

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Sky plot

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M101 with 400mm & 2X teleconverter, TStew