How to calibrate and stack astrophotos from Multiple Nights?! Deep Sky Stacker and PixInsight
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- čas přidán 21. 07. 2024
- Now that we've taken calibration frames, we need to apply them to our light frames and stack to get a final picture to process! Let's do this, using DeepSkyStacker or PixInsight - plus we can complicate the problem by looking at calibration frames taken on multiple nights where lights were taken differently!
Calibration frames cheat sheet: drive.google.com/file/d/1I1de...
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#astrophotography - Věda a technologie
Shouldn't you set one frame as a reference frame from your highest scoring file in DSS? especially if you done a meridian flip some would be upside down :) Get registered for Monetizing Monday :)
Yep I should - thanks for catching that! I was so focused on calibration... Let me pin this comment!
Just watched this one. I'm having a first go at Multi Night Imaging. I found this very informative, THANK YOU.
Good luck!
Excellent! Very helpful video. Thank you! Clear skies!
Cuiv, another excellent explanation, I wish we had something like this five years ago when I stated in this hobby!
Thank you! Yes, I wish I had had that when I started as well... things can get so confusing, and then there are so many recommendations flying around that may or may not be correct.
Cuiv, you are on a roll!!! Another great video. Thank you.
Thank you! It's always my pleasure :)
I really like your videos and they are very informative, for those of us who do astrophotography from big cities, I occasionally go out to the field but the lack of time makes the best option is your own home.
Greetings from Barcelona - Spain
Thank you, glad the videos are helping! And yep - that's exactly my feeling. I should be going out on the field more often, but it's just so much more convenient to image from home! Barcelona sounds just as bad as Tokyo to image from! Clear skies!
Really helpful and well explained videos Cuiv! Look forward to more of your videos.
Thanks for the feedback! The videos will keep coming :)
Thank you for including your mistake about the master light frame that you had to remove. I got that same error and have been searching as to why it occurs. Now stacking 8 hrs of data on the andromeda galaxy :)
A very useful VLOG, thanks.....Plus a wee shooting star 0.17 seconds in (top left of frame) nice :)
Thank you for sharing all your knowledge. This helped me a lot :)
A new great useful video Cuiv! Thanks for it. Never had to use these features before but I plan to start multi-day imaging projects this summer, so right in time! However, I’m curious about your determined preference for PxIn calibrating&stacking over DSS. I think I’ve seen some other comparison made between both tools on which results came out almost with the same quality or slightly advantage to DSS. It could, however, be the case that they used the old calibrating script in PxIn rather that the new you recommend here.
The difference in the stacked result between DSS and PI to me lands squarely in the "too minimal for my laziness" area! :) But I personally saw small improvements after I switched to PI. But that was a while back, it might have changed!I think there's been a lot of debate. I think PI can get better results thanks to the Subframe Selector, and LocalNormalization - but that requires more work from the end user! I've recently had a viewer (Ioan) suggest I try the Entropy Weighted Average stacking method in DSS - and indeed it works fine. Is it better than PI? No idea... Is it easier? No, not with the new WBPP script in PI (except for multiple nights with different calibration frames!). Does it let me select frames based on parameters I choose such as #Stars? No. In the end a matter of personal preference!
Thanks Cuiv. Alway very useful. Just one comment. I have seen people showing that in DSS there is actually an issue. All the calibration frames you put in your first group will also be used as calibration for the other groups, no matter if you add additional specific calibration frames for the others. Apparently, you need to have a kind of “fake” first group, simply adding a light frame from another night (anything will work, just avoid to use lights of the nights you want to stack) and then add each night worth of images (light and calibrations) in successive groups. This way DSS will use the calibration specific to each night. But please correct me if I am wrong...I am still experimenting, but this is what I have seen on Cloudy Nights. Cheers
Is it correct that calibration frames from Main group is applied to all other groups in DSS?
What would we do without you Cuiv, I don't know..
You'd be spending less money for sure :p
Hope you don't mind me posting a question to a video that is 7 months old but I am just now getting around to trying to process my data. I have spent all of my time, up till now, working out the kinks on how to acquire the data. First of all thank you for the video. It answered as lot of the questions I had about once I have my calibration frames , what's next.?
My problem is this...I used the NINA Flat Wizard for my Flats and Dark/Flats and the Simple Sequence for my Darks. All my calibration frames were saved in individual folders buried 4 levels deep and with the same name; not like yours where all the files were in one folder (Darks, Flats, Dark/Flats) and with names that had the date/time/temp/exposure time, etc. All that data ended up as folder titles for me. For example here are the names of the four levels of folders I have to open to get to a single Flat Frame;.
Folder1: 2021-01-18_16-01-27 (Date & Time)
Folder2 inside Folder1: -10.00_0.29_0000 (Sensor Temp/Exposure/Frame #)
Folder3 inside Folder2: 1x1_116_11 (Binning/Gain/Offset)
Folder4 inside Folder3: 0.00 (All the folders for all the calibration frames end in a folder named 0.00).
Also, all the files for a particular calibration frame have the same name: Celestron SPC-8 + 0.63FD.fits - Which is the name of the profile I am using in NINA for this particular optical setup.
Having to go down through 4 folders to get the calibration frame file and then rename each file for 50 Flats/50 Dark Flats/ 250 Darks is more than I want to tackle even once let alone on a recurring basis. I am assuming there is some file path or designation option for calibration files I have misconfigured or not configured. I am sure it is something simple like that but I have spent several hours trying to figure this out with no success. Sorry for the long post but could you help me with my problem?
Thank you very much.
Wow I'm feeling a bit guilty and selfish over the cheat sheet request as you did not even mention it here. So I will plug it here.
*For a written summary of the previous video 'Struggling to understand calibration frames for Astrophoto?' Cuiv has kindly written a handy cheat sheet summarising the video in the comments section of the 'Struggling to understand calibration frames for Astrophoto?' video.*
Thanks for adding this! And don't feel guilty or selfish, it was a great suggestion, it made sense, it's going to help others, and it wasn't a lot of work! I'll also add the link in the description of this video.
As always, excellent video and info. Since you are the smartest geek I know (or at least watch videos of) may I ask your advice? I recently purchased a Meade DSI IV OSC camera. Using APT to take 3 minute subs of M106 things looked okay. When on image was opened in GIMP, again okay. But when I try to stack them in DSS I get a black screen with "no stars detectable" even with the parameters set way down 4%. Is there any advice you could give? Thanks.
Thank you Patrick! Huh, I'm not sure why that would be the case, but often that's because the calibration frames are not properly matched to the lights. Have you tried registering without calibration frames? Otherwise, it is difficult to tell... Good luck!
Thanks for the response and encouragement. I load the files in DSS and try to review an image without any registration or calibration, but nothing but black. I guess I'll just stick to a DSLR.
Simple and instructive Ciuv! I have a question? I want to shoot a session of some nebula with natural stars, so only UV IR cut filter. After that I want to shoot same nebula session with a dualband filter. After that, I want to stack in DSS broadband and narrowband photos separately, but with their stars aligned so that I can extract a mask of natural stars from the broadband and place the same mask on the photo with the narrowband nebula. How to do it? I can't find the right instructions anywhere on the internet
I do a similar workflow in PixInsight for data from multiple nights but I do all my calibrations in one go by utilising the "add custom" button in the WBPP script and then will add other nights as e.g. Red_day2 as the "filter name" for the matching lights and flats. I also will do all the registration and integration in the WBPP script but only so I can have the files weighted (unfortunately the integrated masters are split into different evenings but at least their subs have been aligned and weighted). Then I'll use image integration and use the FITS keyword (WBPPWGHT) and stack each filter in turn.
I want to triple-heart your comment, this is a great idea! I had never thought of that!! My main issue with the WBPP script though is that I don't like the available weight parameters. For me, # Stars seems to work best, and it's not available in there... Still, this is a great method, and thank you so much for pointing it out!!
@@CuivTheLazyGeek yes balancing functionality against laziness is an ongoing struggle :-)
Hello Cuiv - thank you very much for your video, super useful as usual. Do you think the quality is lower for the final master if I create in Pixinsight two masterlights individually for each of the two nights, align them with 'StarAlignment' and integrate them with 'ImageIntegration', instead of calibrating all the images from both nights together? Thank you
Yes the final master will be lower quality if you do that, because you are intentionally sacrificing some of what the averaging process gives you - e.g. you are doing an average of averages, which does not retain all of the individual weights of the frames.
Cuiv, cen you please explain how you go to the same exact frame on the second night if you had to take the scope inside after the first night's work.
Cuiv, thank you for the good explanation. I have not done this a single time yet... sorry for a question. What is registration and integration and what is the difference. I found that people do not make emphasis on that. Again sorry for the question.
Don't apologize for asking a question (and a good question at that!). Registration is basically the Star Alignment before stacking the frames together. So I take all my subframes, and automatically align them together using stars as my reference points. That's registration. Integration is the act of taking your registered frames and stacking them, or in other words taking the average of each pixel value across all of your registered frames. This is why the total imaging time on a target is often referred to as the Integration Time. I hope this helps!
Thank you
Thank you !
How do I apply one set of calibration frames to multiple nights?
Hey Cuiv! Newbie question here. I just purchased an EQ6-R Pro and I'm confused as how to save and recall objects and picture framing. Last night I attempted to image the Heart and Soul nebula in narrowband and right before I switched to my sulfur filter, I accidentally turned off the mount. In the time it took me to turn it back on, my original framing was moved. I've tried multiple times to use the hand controller to save coordinates/objects, but it seems like the mount just returns to the original coordinate without taking into account the time differences between when I saved and recalled the 'object' (since the object is always moving relative to Earth). When I save an object in the hand controller, do those coordinates take into account time differences between saving and recalling? I use the ASIAir Pro to do all of my guiding and plate solving. Can you explain or make a video that shows how you set up your imaging session to capture data over multiple nights including framing up your target? Love your videos!
Hello - the mount's pointing model can't recover from a loss of power. You need to put it back to home position, turn it off and on again, and start from scratch. Alternatively for planned power losses, look up how to park your mount!
Shooting star at 11:45 haha!
I remember reading somewhere on a cloudyskies forum that files in the "Main Group" tab will be applied to all groups in the stack and as such they recommended putting bias frames only in the main group (assuming temperatures are fairly consistent) and then separating the days in group 1, 2, etc. Could someone dispel this for me? Either way I think I will try this way and the way I read and note the differences!
Greetings Cuiv.How do you show the temperature in Fits files?I have the same camera and my fits files are not showing the temperature in the description.Only the exposure length and gain.Is it because I used the AA+ and not Nina?
That's probably the reason! Each piece of software decides what data to put in the fits file header, and so it looks like the AA+ doesn't include this information
shooting star at 11:20
As far as I understood, you decrease your snr, if you make use of flatframes without bias- or darkflats... Why didn’t you just shot some bias frames? It doesn’t need much time...
The previous video in the series touches upon that subject - basically I take dark flats, which also contain the bias signal. I've had too many issues with bias frames on the 294 (bias frames not recommended, should be 2s or more) and 1600 ( 0.1s or more) to trust the 533 to take them well yet. And dark flats are sufficient. My way of doing things though!
i just finished 27 hours of data with 100s of calibration files on NGC-6888 in SHO and RGB ( crazy) , but worth the pain...
WOW!!! I want to see the result!! Or get the data to play with it ;)
@@CuivTheLazyGeek Absolutely ... you will be getting a link to dropbox.com , soon.. Ha + OIII+ SII + OSC= about 30 hours :-)
via PM .. make that Google drive link..
Awesome, I saw the email, I will look at it once I'm back home and have some time. Can't wait, and thank you!
@@CuivTheLazyGeek Yep :-)
For multiple night sessions there is nothing better than APP to stack them all up.
I still haven't tried APP...