yobbo89 wrote: ↑Mon Oct 07, 2019 5:48 am
yes you should be taking flats every night you image per every filter especially if you are using a mono setup or an lp filter,this keeps you at the focus point of your light frames and the crucial one is getting the evil dust bunnies (motes) out of the lights in stacking which can move around from time to time in the imaging train over the course of different imaging sessions.
If you have a rather clean imaging train and not so such much noticeable dust motes ,then taking flats on different nights will be ok given that you are focused well and if vignetting is just your main concern.
Thanks for responding Yobbo. That's good to know. Unfortunately, I had figured this out the hard way, and now have to deal with some angry dust bunnies present in 2 great nights of imaging
I have quite a few dust motes in my imaging train... but I'm still trying to figure out how to get good flats. When I try to do it in AV mode, my flats look bright enough on my
DSLR and in photoshop, but are too dark in pixinsight, which is probably why they weren't working... I tried decreasing the brightness on the iPad
app that I'm using, but it was still too dark in
PI.
If I do it at a 2.5" manual exposure, with my histogram in the middle, and even off to the right, I'm still seeing dust motes in my stacked images. I have a new set of lights and flats from last night's session, taken with a white, semi-transparent trash bag and my iPad. Hopefully those work... They look fine in
PI, just very blue (I'm assuming from my
LP filter).
I have 2 questions tho:
1) If I am using a light pollution filter, and I only used a light pollution filter, I only need to take flats with the light pollution filter on, correct?
2) If I image 2 seperate targets at the exact same ISO and exposure, do I have to take 2 sets of calibration frames for both sets of light frames? or can I just take one set of 30 darks, 30 bias, and 30 flats, and use that one 1 set on both stacks?
-James W.
Telescope: Explore Scientific 80mm FCD100 Triplet APO Refractor
Mount: EQ6-R Pro
Cameras: ZWO ASI1600mm Pro (Cooled) |
Canon DSLR EOS T7i
Auto-guiding: ZWO ASI120mm-Mini +
Astromania 50mm Guidescope
Filters: ZWO 31mm Ha/Oiii/Sii 7nm + LRGB | Orion 2" Skyglow Filter
Accessories: Explore Scientific 2" Field Flattener, ZWO EFW 8 Position
Software: APT, SharpCap Pro, PHD2, CPWI | PixInsight, DeepSkyStacker, Photoshop
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