arminmanhard
Pleiades
On January 23, 2022, we've had a rare clear and calm night, so I tried my luck at the Pleiades cluster (M45) with the TAIR-3S (300 mm f/4.5, stopped down to f/5.6) on the Star Adventurer tracker. This is my longest exposure of any object so far, totaling out just short of 1:15 hours (I'm still a beginner after all). Polar alignment worked out really nice this time, and I think I'm also slowly better at minimizing chromatic aberration. I like how I was able to already bring out quite some part of the reflection nebulae, and how diffraction at the aperture blades of the lens makes the iconic "seven sisters" stand out.
However, now I'm running into new problems, namely a rather ugly, stripey background after stacking; probably some fixed-pattern or "walking" noise, which amplifies due to the good polar alignment (i.e., practically no declination drift) with simultaneous RA tracking jitter of the mount. Ah well... probably means I have to open a new can of worms and get into dithering now (this is going to be fun with a non-motorized declination axis...). Still managed to get rid of the worst of the striping during post-processing, also since the stripes were rather regular and well aligned along the RA direction.
EXIF:
Lens: TAIR-3S 300 mm f/4.5, stopped down to f/5.6
Camera: Samsung NX30 APS-C, unmodified
Filter: Rollei Astroklar light pollution filter
Acquisition:
147 x 30 s (1:13:30) @ ISO 3200
100 darks, 25 flats, 15 flat-darks, no bias/offset frames
(I actually tried bias/offset calibration, but had the impression it rather made the image quality worse, so I kicked the frames out again)
Stacking: Deep Sky Stacker
Post-processing: fitswork
final touches: Aurora HDR 2018, Luminar 2018
Pleiades
On January 23, 2022, we've had a rare clear and calm night, so I tried my luck at the Pleiades cluster (M45) with the TAIR-3S (300 mm f/4.5, stopped down to f/5.6) on the Star Adventurer tracker. This is my longest exposure of any object so far, totaling out just short of 1:15 hours (I'm still a beginner after all). Polar alignment worked out really nice this time, and I think I'm also slowly better at minimizing chromatic aberration. I like how I was able to already bring out quite some part of the reflection nebulae, and how diffraction at the aperture blades of the lens makes the iconic "seven sisters" stand out.
However, now I'm running into new problems, namely a rather ugly, stripey background after stacking; probably some fixed-pattern or "walking" noise, which amplifies due to the good polar alignment (i.e., practically no declination drift) with simultaneous RA tracking jitter of the mount. Ah well... probably means I have to open a new can of worms and get into dithering now (this is going to be fun with a non-motorized declination axis...). Still managed to get rid of the worst of the striping during post-processing, also since the stripes were rather regular and well aligned along the RA direction.
EXIF:
Lens: TAIR-3S 300 mm f/4.5, stopped down to f/5.6
Camera: Samsung NX30 APS-C, unmodified
Filter: Rollei Astroklar light pollution filter
Acquisition:
147 x 30 s (1:13:30) @ ISO 3200
100 darks, 25 flats, 15 flat-darks, no bias/offset frames
(I actually tried bias/offset calibration, but had the impression it rather made the image quality worse, so I kicked the frames out again)
Stacking: Deep Sky Stacker
Post-processing: fitswork
final touches: Aurora HDR 2018, Luminar 2018