M51 13-14/02/2018

Date 13-14/02/2018 (23:12-02:07). M51 The Whirlpool Galaxy. 2x drizzled (non-drizzled attached).

Weather: Excellent clear skies, no wind, good seeing. Clouds moved in at about 02:00.

Optics and camera: Skywatcher Evostar 120 F/D=8.33 (Achromat) with a Baader UHCs filter. The camera was a IR-filter removed Canon 600D.

Settings: 54 x 3 minute lights, 50 darks from library, 100 flats taken the next day and 100 bias frames taken next day. ISO 800.

Mount: Skywatcher AZ-EQ6 with extension pillar. The mount was auto-guided with a synguider (version 1).

Processing: Calibration, registration, integration and basic image stretching all done in DSS. Some tweaking done in GIMP. No problems with the flats this time. The frames were 2x drizzled.

I am pleased with this stack, my best image of M51 IMO. The beautiful spiral structure and bands in between them are visible here. Also the connecting band between the to galactic nuclei is clear; this is not easy to get from my location! I am very happy that the very faint clouds of stars thrown off from the smaller companion (NGC 5194) can also be seen. I never thought they would be within reach of my telescope.

As with the previous image of NGC 2403, the imaging run went well. The autoguider tracked without interruption for the entire session (no wind helps here). Also, because of the accurate PA, all but one of the subframes were usable in the final stack. If only the clouds didn't appear I could have got another 40 subs!