M109 again, with the C11. With the ASI183mm

This is such a nice galaxy! Spiral arms and a central bar, beautiful! After the attempt to image it th elast nights with the C11 & Nikon, again a few nights (nights are short!!) now with the ASI183mm.

Th epixels are a bit small, and the C11 ‘s output is oversampled. In that respect the Nikon’s larger pixels (5µ) make more sense. However, this really worked out more acceptable then the previous attempts.

Using SIMBAD, you can identify some of the smallest and faintest patches in this image. SDSS J115703.88+532414.6 was about the faintest one with a listed green band magnitude of 20,893! The image itself measure 20′ x13′ end has a resolution of 0,6″ per pixel. Seeing was rather bad these nights, with nortwest sea air blowing over. Very clear however, with SQM 20,40 on average.

The C11 was guided with a 8×50 finderscope, using an ASI290MM. Autofocus was done using an Esatto 2″ focuser.

M109 3,8 hours LRGB C11 ASI183 Meldert May 2020
Searching the limiting magnitude
Astrometry from nova.astrometry.net

Testing the C11 without OAG

After cleaning & collimation, I tested the C11 with the Starizona F 7.2 reducer, the ASI183mm (way oversampled obviously), and guiding using a simple external 8×50 guider and the ASI290MC. Just as a test not bad. I’m not convinced the mirror shift did not have influence in this image. Focusing was a pain, needed to be done manually.

C11 Starizona F7.2 reducer flattener 8×50 guidescope, ASI183MM 46×120″ G111 Baader RGB

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