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Hi,
Assuming same camera / optics and filter but imaging target over several sessions [over a period of 4-6 weeks], do you get a better master light if you integrate all lights in a single process than you would by stacking every couple of sessions and then integrate these sub-stacks to obtain a master light for that filter?
I ask this as when I stack a single session I tend not to use LNC, [= quick processing]. When stacking several sessions in a single process and using LNC 1st degree with 3, this seems to add a large amount of time to complete the process. Typical session size would be 60-90 frames. I have found stacking 300-400 frames from several sessions in a single go can take up to 24 hours to process.
Assuming its no real difference are there any key pointers in the settings on the integration tab when combining several stacked images to obtain a master light? E.g would you
- use LNC?
- Kernal droplet size, if sub stacks had this set to 0.5 would you keep the same settings for combining to create master?
- I assume you would not use drizzle and scale as this would have already been applied on the sub stacks?
Any other guidance here?
Thank you!!
First of all, the LNC process is the one responsible for the long processing time. It was never designed to deal with so many subs. We are working however on a more efficient LNC algorithm. For now, I would suggest to stack the sessions and then combine the session stacks. As long as the sessions have more than 50 frames, the final result will not/should not be inferior to combining all at once. For each session, I would advice LNC 1st degree. Then when you combine the session, you can use a hihger LNC degree, but only when the data needs it (read: big and different gradients between sessions).
With regard to drizzle, droplet size only has influence when drizzle integration is enabled. I suggest to use drizzle on the sessions and then regular integration on the session stacks. But ! be careful, if you drizzle with too little frames or too low droplet size, the star shapes are affected by drizzle artefacts which can lead to problems later on 😉
Mabula
Hi Mabula,
The default LNC degree is "no LNC." From your previous post, do you recommend changing it to 1st degree LNC for typical one session stacks?
Thanks,
Jeff
