Author Topic: add more calibrated images?  (Read 2702 times)

Offline alcol

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add more calibrated images?
« on: 2017 September 07 12:17:56 »
A simple question that I am unsure of the answer.

I took 20 of images of M31 a few weeks ago, calibrated them and integrated them into an image (say image A). If I take more images of M31, same setting, and calibrate them, can I register them and integrate these addition images directly with Image A or do I integrate them with the original 20 calibrated images?

Thanks for your help.

Offline sreilly

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Re: add more calibrated images?
« Reply #1 on: 2017 September 07 12:30:05 »
All being equal I'd recombine all the individual images using the proper combine method. or 1-6 images I use Percentile Clipping, 7-14 Sigma Clipping, 15-24 Winsorized Sigma Clipping, and Linear Fit Clipping for 25+ images. I found this reference some time back when 1st starting with PI.

Steve
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Offline alcol

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Re: add more calibrated images?
« Reply #2 on: 2017 September 07 14:43:47 »
Thanks Steve, appreciated

Offline John_Gill

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Re: add more calibrated images?
« Reply #3 on: 2017 September 07 23:14:24 »
Hi,

For Session1 - I calibrate the Bias, Darks & Flats into the Masters, then I process the Lights with Calibration, Cosmetic Correction and Debayer
Repeat for Session2 etc etc.

Then "Star Alignment" for all debayered images from all sessions and finally "Image Integration" to produce a final result.

I would assume that if you are working with LRGB or NB the procedure is the same, except there is no debayering.

Look up
John
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Offline sreilly

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Re: add more calibrated images?
« Reply #4 on: 2017 September 08 06:26:52 »
As a user of ACP automation imaging software my imaging may span several seasons for some of the same objects depending on how deep the image is intended to be. The images are all saved in the same named folder and then I calibrate accordingly. My naming scheme for the raw images includes the name of the target, UTC Date and Time, Bin Rate, PA, side of pier (E/W), filter used,  and Temperature. So a raw images in the folder looks like the attached screenshot.

My processing does not use the Batch Pre-Process script as I prefer to take multiple steps and calibrate, do cosmetic correction, star align, and then image combine in individual steps. I save the results in separate folders under the image name such as attached. One reason for this is that all software I've used can not pick the appropriate flat to use as I have east side images and flats as well as west side. There is a difference due tothe fact that the imaging train is not dead center of the optical path so flats are not identical. Saving the individual images gives me the ability to step back if needed and redo from some point other than the beginning. I also use some form of id when saving master images such as NGC6960-262431_HaO3S2 which tells me I have 26 Ha, 24, O3, and 31 S2 images in this combined image. When I crop the image it becomes NGC6960-262431_HaO3S2_c, use DBE and it goes as NGC6960-262431_HaO3S2_c_dbe and so on. Saving each along the way. Hard Drives are cheap these days.

My M33 image being taken at SRO started back on 10/5/2016 and the last image was taken 09/01/2017. Tis started as a late project and carried over until the plans needed exposures were all taken. I calibrated the images usually as they were taken the day after and saved to the folder. Once a star alignment was done and saved under the M33/PI folder I could use any of those aligned images to align the new images as they were processed and saved. When it was time to assemble the final image instead of having a massive amount of data to process I just needed to use the images in the PI folder that were already calibrated, cosmetic corrected, and aligned to combine and make the final masters.

At any point in the stage of acquiring the data you can assemble masters of the image to see the progress of the project. As stated above, when I save these I indicate how many frames are being used such as M33-11_L as a 11 image combine luminance image. The processing side drops the UTC Date/Time/ PA/Temp/Bin Rate/Pier Side info as they are already calibrated and aligned. At this point I'm only keeping track of the processes used and saved as along the way. I use Masked Stretch and will add say MS16 to indicate the level I used to stretch instead of the default 12.6 which if used would be MS125 Hope this makes sense. I find it gives me the ability to control all aspects of the processing journey and ability to go back to any step and change things if needed/wanted which happens often as you learn more and become more experienced. Happens to me on a weekly basis....and then I forget something which seems to happen on a more frequent schedule.........

Steve

« Last Edit: 2017 September 08 06:57:03 by sreilly »
Steve
www.astral-imaging.com
AP1200
OGS 12.5" RC
Tak FSQ-106ED
ST10XME/CFW8/AO8
STL-11000M/FW8/AO-L
Pyxis 3" Rotator
Baader LRGBHa Filters
PixInsight/MaxIm/ACP/Registar/Mira AP/PS CS5