The main project for the last month. My main goal was to get at least some of the faint tidal streams off the Hamburger (NGC 3628). However, I kept running into all sorts of issues on this target. Initially rather routine, it ended up being quite a nightmare. Overall, the integration had to reject around 40% of the images I had taken due to some of or all of FWHM, Eccentricity, SNR, or low star count. Out of the 667 frames that looked fine initially, only 432 made it through in the end.

I'm pretty satisfied with the details I managed to get out of the Triplet themselves. The Quadband filter is good for getting those reds and dusty details out of the galaxies. However, I think it may have played a part in not being able to really capture the tidal stream well. 

In some of the earlier negatives and extreme stretches, I could barely make out the tidal streams.



As a result, I got really excited. However, the more I integrated the less obvious it ended up being. On top of that I had to deal with a plethora of issues such as the ASIAIR refusing to focus or when refocusing focusing in the wrong setting some nights leading to a terrible FWHM (one of them I presume MIGHT be an atmosphere thing but I'd rather blame the equipment than something I couldn't control), the object approaching the horizon later on leading to worsening HFRs, the full moon being next door for a couple of days, the usual clouds, etc. On top of that, when combining UVIR filters and Quadband images for stacking, ASTAP kept introducing the weirdest artifacts (included below).


In the end, I ended up having to do some roundabout methods for integrating the images.

Overall, I feel pretty defeated and fed up by this target but it's always a learning experience. On the upside, I'll come back in the future and be pretty happy with my progress when I get that tidal stream off the Hamburger. I still need to learn how the ASIAIR does its focusing routine as it's starting to cost me perfectly good nights. PixInsight also does not stack slowly because my data is on my external HDD but because it's just slow. 

Processing method (this time it's rather different):

1. Blink and calibrate using 20 Flats, 20 Darks, 100 Bias per day in ASTAP
2. SubframeSelector in PixInsight FWHM < 4, Eccentricity < 0.7, Stars > 180, Median <5000
3. BatchFormatConversion of XISF to Fits
4. BatchFITSKeywordEdit convert all the UVIR to QUAD so they stack with the Quadband
5. WBPP max quality no drizzle, autocrop 4 hours +
6. GradientCorrection
7. SPCC
8. BXT Default
9. NXT 0.6 Denoise Default Details
10. GHS and blackpoint shift
11. Range selection galaxies
12. CurvesTransformation boost saturation