Celestial hemisphere:  Northern  ·  Constellation: Ursa Major (UMa)  ·  Contains:  M 101  ·  NGC 5447  ·  NGC 5449  ·  NGC 5450  ·  NGC 5451  ·  NGC 5453  ·  NGC 5455  ·  NGC 5457  ·  NGC 5461  ·  NGC 5462  ·  NGC 5471  ·  Pinwheel galaxy
m101 - still looking for new setup optimization, Stefano Ciapetti
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m101 - still looking for new setup optimization

m101 - still looking for new setup optimization, Stefano Ciapetti
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m101 - still looking for new setup optimization

Equipment

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Description

This image, heavily cropped, is the result of 5 nights of imaging during march 2022. In these 5 nighs I have imaged at bin 2 and bin 1 with the amazing QHY 268m, combined with my Newton F 3.9 250 Orion USA,  a Sharpstar 1x full frame coma corrector and a Primalucelab UHC filter. All on top of the Ioptron CEM60 EC. Not all the nights I have been able to collect photons for the whole night, for issue explained below but also for wind and clouds. Total exposure approximately 18 hours.

The 268M is an a great camera. But with a few issues, especially when imaginig at bin1, maybe not depending on the camera, but on the pc (my aquiring pc is a celeron with 8 giga ram and 128gb hd). Suddenly, during the night camera starts having problems and download only a black image. On the night of 28th I have lost in this way over 300 60 secs frames. This is not happening at bin2. Probably I can solve this disconnecting and reconnecting the camera every time this trouble occured via script (I sleep while the camera collect photons). On the other hand, imaging at bin 1 gives amazing results.

The main issue I have found out is with the coma corrector. That coma corrector, which seems a clone of the GPU create a crazy vignetting that I have trouble removing even with flats. That's why I have published only the center of the galaxy. Actually looking for a new coma corrector. On the other hand with this corrector  stars are very small on the full size of the sensor. Much better than the Baader MPCC.

Last issue is the color part. I have put on top of the the Newton a C5 with F 6.3 reducer and an unmodded Nikon d5300 in order to collect color images. Still not happy of the results. Must change some parameters in order to get acceptable images.

Anyway experimenting is nice and the 268M deserve it.

The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy 21 million light-years (6.4 megaparsecs) away from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the Messier Catalogue as one of its final entries. (Wikipedia)

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  • m101 - still looking for new setup optimization, Stefano Ciapetti
    Original
  • m101 - still looking for new setup optimization, Stefano Ciapetti
    B
  • m101 - still looking for new setup optimization, Stefano Ciapetti
    C
  • Final
    m101 - still looking for new setup optimization, Stefano Ciapetti
    E

B

Description: lowering levels in order to hide gradient

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C

Description: increasing levels in order to hide gradient

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E

Description: local contrast increase in the galaxy core

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m101 - still looking for new setup optimization, Stefano Ciapetti