Celestial hemisphere:  Northern  ·  Constellation: Ursa Major (UMa)  ·  Contains:  M 101  ·  NGC 5457  ·  The star 84UMa  ·  The star 86UMa  ·  The star ιBoo  ·  The star κ2Boo
Pinwheel Galaxy - M101 - 135 mm Widefield test, JanD
Pinwheel Galaxy - M101 - 135 mm Widefield test
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Pinwheel Galaxy - M101 - 135 mm Widefield test

Pinwheel Galaxy - M101 - 135 mm Widefield test, JanD
Pinwheel Galaxy - M101 - 135 mm Widefield test
Powered byPixInsight

Pinwheel Galaxy - M101 - 135 mm Widefield test

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Description

Hi,

yesterday I had the chance for several tests, the conditions were not perfect, clouds from time to time so I chose to do some experiments.

First I wanted to check how big the "smaller" galaxies are in 135 mm, if it is possible to see some detailed structures. The image is slightly cropped, but M101 and a few neighbours are at least visible. I think I will try this again soon with a 180 mm lens.

Second was to check how this old pre ED lens handles star colors wide open (f/2.8). Here I see some real problems, the brighter stars get a huge blue halo and color aberrations. Nevertheless the light collection ability wide open is impressive, the total exposure is only 27.5 minutes.

Third was to check different ISO settings. I had troubles with noise & color when I used ISO 1600 as before. Here with ISO 400 it seems much smoother, according to the web I could also go down to ISO 200 with the Nikon D7100.

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Pinwheel Galaxy - M101 - 135 mm Widefield test, JanD