Sh2-173 is a very dim emission nebula in the constellation Cassiopeia about 8800 ly away from us. Besides the Ha-emission nebula there are a mass of stars in the field of views. The star cluster in the top right is catalogued NGC 103.
This is the first image taken with fun after I returned from my (astro-free) holidays. Some days before I travelled I had switched from MGEN guiding to Phd2 with an ASI120mm-s because the MGEN still has trouble with the automatic meridian flip in NINA. All was fine and smooth with Phd2 before but after my return I could only produce egg-stars in longer exposures, though the phd-guiding was around 0.8" total RMS and the graph did look fine most of the times. After a lot of tweaking, optimizing and a complete de- and reconstruction including precision PA and everything you can imagine the graph was even nicer but the eggs continued rolling in . Because I did not want to spend the whole clear new moon phase with testing and frustration I put the MGEN back onto the scope yesterday - and ALL WORKS FINE (puh!).
Here the image:
On Astrobin: https://astrob.in/full/4t4zas/0/
TS 130/910 mm apo with 0.79x reducer attsched to an ASI1600mmp.
APP, starnet++ and PS 2020.
50 x 200 s Ha
50 x 60 s red
50 x 60 s green
50 x 60 s blue
CS and stay well
Edited by Pete_xl, 21 September 2020 - 09:24 AM.