2022-05-29: APP 2.0.0-beta2 has been released !
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Workflow for multi-session, mosaic with HaLRGB data
I have access to a multi-session, 4 panel mosiac dataset for M31 with HaLRGB subs. I've (very) new to APP but reviewing the published tutorials, it seems an appropriate workflow for a single session is to integrate the individual panels into RGB and then build the mosiac from the panels.
However, with multi-session data, how does this workflow change? Should each panel be integrated across sessions and then the mosaic built, or, create the mosiac for each session and then stack the resulting panels?
Appreciate tips and pointers to previous posts on this subject.
@snapthot In APP multiple sessions only are necessary if different calibration data are used per session. If all sessions use the same calibration data then the data can be processed in one session. So if you have, say, L data for multiple nights and you have a set of flats for each night, then you should load the L data for each night in a separate session.
Note that, for APP, data for different filters in general are not considered data for separate sessions. It is perfectly OK to load lights for the L, R, G, B and Ha filters in one session and assign them to their distinct filters. Then you need to do the same with the calibration data and APP will happily integrate them in one go. Note that combining Ha and L data with RGB data (in other words, combining mono and color data) currently doesn't work in APP.
Apart from that, whether a mosaic can be built from the raw data or it is better to integrate the individual panels first largely depends on the number and quality of the raw images. If you have a lot of panels, or if the raw images are subject to light pollution that introduces gradients, then integrating the individual panels first would be a better approach.
As you can see, there are a lot of IFs here. I hope that I was able to help you this way. Feel free to explain more about your data and to ask questions about what would be the best approach to process them if it wasn't.
Thanks Wouter. I was able to get some good results using a slightly different data set (LRGB, no Ha) but still 5 session, 4 panel.
I integrated all panels in 1 session and APP did a nice job sorting it out. Somewhat counter-intuitively, I had to dial back LNC and MBB to reduce banding (1 degree, 5 iteration and 5% respectively). I also had to do a final touch up in Lightroom to adjust black level and mid-range contrast ... might have been able to do in APP but couldn't find a way.
Data was captured on the NYAA Lorenz telescope (130mm Astrophysics Starfire EDF with SBIG ST-8300M). 25 min total exposure on each of LRGB over 5 sessions.
Overall, I'm pretty pleased.