Do Your CMOS Images Look like THIS?? (Part 1)
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- เผยแพร่เมื่อ 1 ต.ค. 2024
- Learn how to fix common imaging problems at AdamBlockStudios.com !
Part 2 (the solution ) is available to members at www.adamblocks...
This lesson highlights a common issue and how to solve it using PixInsight. Both the methodology of solving problem as well as ways to get "unstuck" are covered. In this particular example, Fine Tuning of a Flat compensates for the problem- but ultimately the complete solution yields the best result!
These three videos are extremely helpful. Encouraged me to get to the bottom of inverse vignetting from a samyang 135 @f2 Calibration now works fine. Solution was for me to realise that I was handling the optimising of darks incorrectly. Thanks. Des
You will enjoy my video on Optimization.... th-cam.com/video/y9qzQnyzMsc/w-d-xo.html ...I get a spicy in it. lol
Oh nooo Adam, its a Cliffhanger:-) I was so patiened waiting for the 2nd part. So many people have similar Problems at this time, i started researching for my own Video, but there ist still a lot of other work. You already have the solution, now i´m really curious.
Hey Adam I have learned alot from this video thank you! What do you do if the master has dark corners?
Hi Adam. The issue I'm having with my flats when they are just subs stretched in NINA is that they look to have reverse vignetting. They are lighter in the corners. I can't work out for the life of me what's going on. I have an Altair Hypercam 26M and Altair 70 EDQ-R quad APO with a Pegasus Indigo filter wheel and Altair 6.5nm SHO filters. I'm using an EL Wire panel. It doesn't matter if I have a pillow case between the scope and the EL panel or not, I still get the lighter corners, all four corners. I've tried taking the flats both in the day and at night in a dark room and it makes no difference. I've checked to make sure both the filter wheel and camera are tightened onto the OTA properly. Can you advise please?
Thanks Adam -- sitting tight for part 2
Thanks for this. It helpt me to get my calibration right again.
Cheers 👍
You had quite a list of suggestions on FB- some OK but not relevant, others completely wrong. That is why I make videos like this- I have seen the likely/sneaky issues many times. This kind of experience is what I bring to all of my efforts at AdamBlockStudios and lessons you will find there. :) Trying to be persuasive here...
@@AdamBlock
Yeah, I was sifting through the answers trying to get the best ones.
I'll check out your website 👍
Random but sort of relevant to the video. all DSLRS usa a cmos sensor. I have seen these dark rings around my images (i use a dslr). I think it has something to do with the dark frames because I never really us flat field calibration until literally this Christmas were my first i processed with. Instead, I use false flats from astronomy tools action set. But I have had this issue with some of my astrophotography images when using just dark frames for calibration. Clearskies turn out your lights at night!!!
Take your darks at night was well! (hint hint)
Awesome I just seen this. Thanks for the response!
Ever since I got PI, I've been using this tutorial that I found online. Just realised the other day that the calibration steps in that tutorial aren't quite right - they suggest calibrating the individual dark frames with a master bias.
I recently got the ASI2600MM & would you suggest doing flat darks or can I just calibrate the flats with a master bias & master dark (not pre calibrated!) ?
Listen, the information you are looking at is both old and confusing. You do not need calibrate your darks with biases unless you are optimizing/scaling the dark- And you shouldn't be doing this with matched darks until you have proven it matters (usually it just messes up stuff). I explain this in the WBPP series and go into more detail in my lessons at AdamBlockStudios.com . I recommend learning how to use WBPP so that you will not double subtract/calibrate images. Let me repeat, many CMOS imagers do not take kindly to optimizing/scaling darks- this should not be a default and LV is 100% wrong here. You should calibrate your flats with EITHER a matched dark or a bias (not both). The only difference between a bias and a dark frame is extra electrons that accumulate through time. Please watch lessons #3 and #4 of my series... th-cam.com/video/sZmHbxIxZeM/w-d-xo.html
@@AdamBlock thanks mate, I'll take a look when I'm able to. I just wish I'd realised this sooner. Wonder how much the difference will be if I go back & process my images all over again. Thanks again for the work that you do :)
Eyeopening! ...and who would have thunk! Tis time to rethink my flats exposure times. I just watched Part 1, 2, and 3. Make sure that you watch all three if you have an CMOS sensor.
Thanks for checking this out! This is a great example of knowing what to look for in terms of sensors that have stale dark frames... that is really what this lesson is about. Flats should do a pretty good job in general. If you have not reviewed the new WBPP 2.0 vids... please do!
@@AdamBlock I might add, even though I am not John, I could very well have been. This was my problem and my darks were not that old. However, when I reshot my darks the problem was solved. I do have one puzzling thought, how in the world could a 180 second dark have lower readings than a 2 second flat. How did a dark get stale in the first place.....logically I can understand more hot pixels due to sensor changes but losing what I assume are luminosity values over time is beyond my logic. The lesson I learned from our work was - toss the supporting file libraries and reshoot supporting files at least within a few days before ore after an imaging session if not the same night. BTW, Adam I have finished the Fast Track and Foundations course, and I am moving through Horizons. I cannot compliment your instruction enough. Fast Track - Foundatioins - and Horizons should be part of any PixInsight user's studies. Period!
@@nightskyimaging Thanks for that Ed. Concerning the sensor- the electronic signature appears to be variable for this sensor/camera. This is an electronics thing...and apparently with this camera/sensor you need to monitor it closely.
@@AdamBlock Tis my guess I own two of the same kind as my ZWO cameras both need "image day" supporting files.....or ones that have been taken very close to the image day. I can work with that....just tickled to death I now know both the problem and where to look to see if it is happening on other gear. Well done!
Love the "alias" only to show her name somewhere else.
She gave permission... so I didn't worry.
Looking for part 2... :)
Hi, I have a question. SharpCap makes master flat-dark. Could I use this file in Pixinsight? It somehow doesn’t work and doesn’t fix vignetting. Why? SharpCap makes master darks and they work fine. But not master flats.
Thanks.
Ana Ta, the best thing to do is load the raw files (flats, darks, lights...etc) in PixInsight. Specifically I reccomend WBPP which is designed to specifically help you configure the proper calibration and get good results. I have an entire (lengthy) series all about WBPP. I strongly recommend investing the time in reviewing it. It explains much more than just how to used WBPP. To directly answer your question- the masters from SharpCap may or may not work depending on the format of the data and what was done with the bias. Remember darks used for flats are DARKS (not flats).
@@AdamBlock Thanks a lot! I will research into this and experiment with different settings based on your videos. I will try to use pixel math as well; just as you have shown in Part 2. Thanks again. All the best!
@@anata5127 The pixel math trick isn't a solution really.. it just demonstrates the image was not properly calibrated. You need to address the core issue. It is best to start with raw data- not a good practice to mix data processed with multiple software programs.
@@AdamBlock Ok. I know many people who get under or over corrections for flats using the same software. NINA for getting flats, and Pixinsight for processing. For example, what was actual problem roots for over correction in example that you have shown?
@@anata5127 I explain in the third part. The issue is that the dark frame is bad. Once new darks were taken- everything was good. Another common way to have this problem is that people not know understand how to manage the bias. If you leave the bias in a flat- or subtract it twice-it will cause this problem.
Great series on flats!!
Thanks for checking it out!