Let's take some flat frames - the simple way!
Вставка
- Опубліковано 21 сер 2024
- We've done this topic on the channel already, but it never hurts to reiterate! Note that with modern cooled cameras like the 533MC Pro, flat darks and bias are essentially approximations of one another - and thus bias could be used to calibrate both flats and lights (with no need for flat darks). And flat darks could be used as bias frames. I personally keep it simple with lights, lots of darks (which includes bias), flats and lots of flat darks (which also include bias).
Joining the channel as a member: / cuivthelazygeek
UA-cam Merch shop: / @cuivthelazygeek
External shop link: cuivthelazygee...
Patreon: / cuivlazygeek . No perks associated, just if you want to throw money at me :D
If you wish to support me and plan on buying astro equipment, please consider buying through OPT using this affiliate link!
bit.ly/2OIw6jH
Follow me!
My Instagram: / cuivlazygeek
My Facebook page: / cuivlazygeek
Member icons: Designed by 3ab2ou / Freepik
Emoticons: Designed by macrovector / Freepik
Order of the Lazy Geeks slogan: Christopher T
Merch Design: Radu Chelariu
I prefer "tomato frames" over dark flats :)
Bonus points if you use the word without any context in one of your videos :p just kidding of course, but it would be so fun to hear you say "I then took my usual calibration frames, darks, flats, tomato frames and this was the end result" ! Thanks for stopping by Trevor!
@@CuivTheLazyGeek you say tomato......Trevor in Canada says "Tomaaatoo" :)
Back to basics... TomatE !!! 🙂Arriba Arriba !! Clear salads and skies guys... x
Excellent clear jargon free demo. Great help for a beginner. Thanks
Glad it was helpful!
Excellent as always, Cuiv.
Always encouraged by your enthusiasm, thanks Cuiv
Thank you! You did a great job of explaining this process. I cant wait to try flats in NINA and someday I hope to have a Flat Field Generator so I can look pretty too! LOL
Looking pretty is the main purpose of a flat field generator :D
Always good for a refresher! Thanks Cuiv, love your videos as always!
Thank you!
Thanks Cuiv, informative as always, and very entertaining 😁
Glad you enjoyed!
Thanks, dude! Awesome info 👍
Thank you!
I love the graphic description of teashirt 😂😂
Thanks Cuiv. Have never used the Flat Wizard in NINA. Now I know how to do it. Thanks for the video!
Glad it was helpful!
Thanks! You really helped me out:)
Glad I could help!
What I use to take my flat frames:
I put a t-shirt on my scope during daylight just before the sun sets, I launch the nina's flat wizard and that's it😄
Yep, that works too! I mentioned dawn sky, but dusk sky works just as well :)
This helps a lot - Thank you...
You made it sound so easy Cuiv I'm still working my way around NINA but beginning to get there slowly great video as always.
Thank you, good luck, and clear skies!
I’ve been using a tracing panel for exposing flats over the last few months. I made diffusion masks from white t-shirts and embroidery hoops to go over the front of my various telescopes or lenses. It took some exploring and mods to this working reliably, but now I’ve got a system that works for my needs. I use the APT CCD Flats wizard to generate a plan for flats and it’s really streamlined this part of the process. After every imaging session I gather the necessary calibration frames, beginning with the flats. I like your straightforward explanation of the why and how, concerning flats.
Sounds like a great process David! Thanks!
@@CuivTheLazyGeek it’s simple and works for me.
Thanks Cuiv! Nice video, great info.
Thank you!
Great refresher and seeing NINA in action.
Smooth as siiiilk, wonderful 🤣 amazing Cuiv!,,
:D Thanks Jose!
very helpful. Thanks
Can you make a video how to make flat frames with the dwarf II?
Ha ha, it must be serious - when I search/look at all your "flat" videos! In the final moments, I was expecting the "show" to somehow end with the fading/turning the lights off - not sure why...
Thank you, you’re amazing 🎉
"Dirty Dirty astrophotographer" omg made me lol🤣. BTW Cuiv if you take images over multiple nights and basically leave the image train unchanged do you always take flats for each night? If I am lazy I tend not to but should I ?? Thanks Cuiv.
Oooh no I am far too lazy for that! As long as I don't touch my imaging train, I'll be reusing my flats over and over, even over weeks or months. Surprisingly, it works very well - turns out those small forces that hold dust motes in place or quite resilient!
@@CuivTheLazyGeek Ah good to know I can also be this Lazy thanks Cuiv.
i have a flatpanel without a dimmer, and put a few sheets of white paper over it to diffuse it a bit and to get the right ADU.. and then used the flat-frame wizard in SGP to calculate the times (in a few days I'll set this up in NINA)
My Oiii flats are a bit over 10 seconds, while my Ha and Sii are around 3.5.. just shows how little light gets through them..
That works well as a method as well, thank you for sharing!
Thank you!
Thank you!!!
No broke don't fix it .... Great, perfect philosophy....👍👍
Can it be a white towel, to comply with the Hitchhiker's Guide to the Galaxy rules with just one piece of cloth? 😂 Loved the video, thanks!
hahaha that works too! As long as it's a smooth towel (like towels for newborns!) :D Bonus points if 42 is written somewhere on it too!
We love you ,too!
Awww, thank you
I use a tracer board with a USB plug and I can adjust the level of brightness. I never had issues with the flats although i see so many people just don't want to take flats, like it's rocket science. It is science, but not rocket.
I think you start hating flats once you get an 294MC camera - those can be really annoying to work with...
question answered thanks
How are you my friend in astrophotography?, well I hope. Many years ago I bought a 7 filter wheel with RGBHa plain filter and a black filter for doing dark frames and also an opal glass filter for flat frames. I had a remote change switch as well as the USB connector, this way to take darks and flats all I had to do was press the appropriate switch with the scope pointed at the zenith, either dawn or dusk sky. It meant that I always had the filter wheel attached for all uses. The improvement today is a flat light panel, as you say, a luxury. Stay safe, greetings from Tasmania 42 South.
That sounds like a very smart way of going about it! Hope you'll enjoy the upcoming summer down under :)
@@CuivTheLazyGeek Thank you, according to our weather forecast Tasmania could have snow down to sea level over the weekend, heaviest in years. I think 1996 was the last time. Should be fun and remind me of mild UK winters! Take care in your bright skies. I recently got my hand on a Nikkor lens, 300mm f/2.8, along with its telenegative 2x lens system making it 600mm f/4. It is pin sharp, I also got a fairly rare Takumar 300mm f/4 which is also pin sharp. I am hoping to try them out with various ZWO cameras on the SW AZGTi EQ. Mount that I saw you improve on in one of your video’s. I have the ASI air pro (second version still to use) it takes a while to get all the bits and pieces together. Your own experience with ZWO equipment is very interesting, I have many ZWO gems, but due to health issues, some have yet to capture any photons! Note-the front element of the Nikkor lens is 5.25 inches, also very heavy. It will be interesting to see how it performs at different apertures. Also at f/2.8 it is very fast compared to many telescopes.
Automagically 😂😊😊
Always :D
I think you have started something.....I will be shooting some flat and dark tomato frames tonight for my bubble nebula shots.
It will likely be very useful :D
Thanks Cuiv, great video with some new pieces of new info, as always! May I ask you if you use the Weighted Batch PreProcessing Script in PixInsight to make your frame calibrations or some other? I dont see the possibility to add FlatDarks in that script... If not, should I use the ImageCalibration process entering the Flats as the frames to calibrate and the FlatDarks as Darks for such calibration? Are Bias also needed in the calibration of the Flats? Too may questions, sorry... :)
I use the Weighter Batch PreProcessing script indeed. I'll have a video of it coming soon. Just input your dark flats as Darks in the script - PixInsight will match them to your flats based on their exposure length. Or you could use the dark flats just as bias, since for modern cooled sensors, essentially 1-2s exposures = bias exposure.
No separate bias needed for flats calibration with modern sensors. Just dark flats is fine (and the dark flats, as well as the darks, contain the bias in the first place).
My flats are never that dark even with exposures less than a second
Is that lightning in the background? Lovely catch!
Hi Cuiv. Thanks for another great Vid.
Quick question: is it okay to take both Flat-Darks AND Bias frames. Or should it be one or the other but not both? Thanks again.
Interesting. With a DSLR in AV-mode, my flats are usually around 1/640. I usually shoot them at the same ISO as my lights, I know this is perhaps not necessary, but I've found that when I do this, my flat frames finally work and I'm afraid to change it up again.
Yep that makes sense - if the flats work for you, then no need to sweat it over the details!
I'm confused, at the first of the video you say to leave the camera in the same orientation and position as the lights yet later you say that you take your flats in your house. Are flats, something you can do 1 time and just reused for all later sessions?
With 1 to 3 second exposure time , I would think your ISO would
Have to be very very low and/ or the light source be extremely dim so as to not every expose .
Can you please elaborate more on brightness , your ISO setting and the exposure time
Thank you
The light source can be extremely dim - my flat panel has adjustable brightness
Great video Cuiv. I have a ASI2600MC Pro (usually cooled to -15C) and someone said I don’t really need darks with that camera because today's cooled astro cameras are so quiet that you can definitely get away without using darks and just using hot/cold pixel correction in software. Would you agree?
It's probably true. You could likely have the same effectiveness with just bias/dark flat calibration. But I prefer to have darks since they're so easy to take on cloudy nights!
Hi Cuiv!
Great reminder video about frames!I Since I use N.I.N.A. and your tutorials to take flats and dark flats, my images improved a lot!! Thank you very much !🙂
By the way, for some reason NINA doesn’t show anymore a preview of the flats and the histogram in the imaging tab doesn’t work either. Do you maybe know why? The flats are anyway so no big deal.
Thanks again!
Try to go to Options - Imaging, and click on Reset Layout (bottom right), maybe that will help!
Thats what i always HATE. Doing that bias, dark and flats after a session. in my case, ive a cooled cam, so its much easier - but i dont like it
Yeah I agree - it's always such a pain...
Thanks for the video. How do you know that the exposures should be at least 1.5 seconds? I've looked online and can't find anyone explaining how bright the light should be if using an artificial light source. I tried using my computer screen and wondering how bright ideally my screen should be and how close I should have my camera from the screen?
Can you provide a link for that circular light?
Thanks for yet another useful tutorial Cuiv. I’m currently transitioning from APT to NINA and it’s a tremendous piece of software. How is the new Polar alignment tool performing compared to Sharpcap Pro? 🤔
Not sure yet! Too many things to test and weather has not been nice...
Bonjour,
comment traiter les flats avec les dark flats ? Est-il possible de les taiter automatiquement dans Siril ? Direct dans le dossier "flats" ?
Merci bcp.
Cordialement
Marc Bordeaux .
Cuiv, after using the Artesky for a while, are you still happy with it? I’m reading on CN about issues of com ports and the computer not recognizing the artesky. Hopefully these issues from the 2020 thread have been heard and fixed by the Artesky folks…thank you. Gary
I don't have the USB version - and for now the Artesky works without any issue, at least for me...
Cuiv.....nice vid. Have you tried the Auto Flat feature in the ASI Air Plus ?? Interested to know your opinion ....thank you in advance
The auto flat seems to expose a bit above 50% histogram - so for now I've been doing my flat frames manually...
@@CuivTheLazyGeek agreed on the 50% ( or more )....I use a tracing light panel for flats and have experimented with getting the Histogram around 30% with a manually set 2 second exposure on the AAP. Ended up putting 4 sheets of computer paper on top of the objective then the light panel...voila ! Then I ran the Auto Flat feature on AAP.....it also calculated a 2 second exposure with the same setup. I guess you still have to out smart the AAP sometimes.
Cuiv, how would you do this with your sct 5" with your Hyperstar installed? I have a 8" with hyperstas and a ZWO ASI533 pro and wonder how I can do this with the soft Celestron dew shield
How would I use the T shirt way for the Dwarf?
What about light tablets for drawing ?
It has a soft LED panel and it is waaaay cheaper than light box.
Didn't try one but I think I will buy one for my Newton.
Joes Astrophoto uses one he got on amazon, he made a video about it says it works fine.
Yep, I've heard many people use those - as long as the exposures are over 1 second, it should work fine!
@@billmurphypenguins3774 I use an inexpensive tracing panel from Amazon and it works great.
Any idea why NINA preview shows flats taken through an l-extreme, completely yellow with two distinct separate peaks in the histogram yet when opening the files with any other fits viewer, they seem correct? Is there some hidden setting in NINA to mess with color balance? Happens only for flats. Using the same Artesky flat field generator. The camera is a 2600MC.
Not sure - try checking and unchecking Unlinked Stretch in Options -> Imaging
When you put FFG on the telesope, you moved dew shield down. Would that not change the vignetting and hence flats will not match lights?
Very good question! A properly designed dew shield would not introduce vignetting (or so little vignetting that it is negligible vs scope vignetting). In practice with the small dew shield of the refractor, it doesn't change vignetting. And many people take flats after removing the dew shield (for SCTs for instance - I did that with my EdgeHD) without issues. Technically you are right, but in practice I've never encountered a scenario where that happened.
Hi Cuiv, (got the T-Shirt, really cool !) how should I consider the tomato frames with Siril in the predefined scripts ? As bias frames ?
Awesome Alain! What color did you get? I'm not sure whether Siril is smart with dark frames and applies them to the flats or lights depending on exposure length. Assuming that Siril doesn't do that, then I would likely put them in as bias frames
@@CuivTheLazyGeek thanks Cuiv for the answer, I will try it and see. T-Shirt is a black one.
Do you think there is a way to take flat and tomato frames with a Dwarf II? And is it worth doing it?
For now I haven't seen the need for either flats or tomato frames (sometimes called ketchup frames)
Love the video. 😂😂
Thank you!
I dont understand... You just said don't change any settings yet you want us to adjust the camera so its not over or under exposed?
Sorry on such old videos, if you need help please include a timestamp
You are so practical Cuiv :D ... but seriously, when taking darks4flats and flats of 2s you REALLY don't need to cool the sensor ... there is no time for any dark current to build up anyway but even if it was, the darks4flats will take care of that. I know you like to err on the side of caution, but in this case this is really unnecessary. Save the cooling energy - save the planet ;)
Something else I will have to test - I do remember testing bias frames a long time ago, and seeing that cooled bias and hot bias were quite different (even though I thought they would be the same), and that's why I'm conservative here...
@@CuivTheLazyGeek Are you talking about the ASI 1600? This sensor indeed has some strange behaviour on min-exposure lengths. In that case, maybe you are right, taking darks4flats and flats at the given light-temperature might be the safest bet ... however:
A bias frame is just the sensor's electircal activity, nothing else. In a fraction of a second, there is no possibility for thermal noise to build up so it is not the temperature introduced by cooling but rather something power related. Which isn't good ... Since it is electrical activity, that is causing bias signal, I would check everything power-related for errors. If your camera is not powered sufficiently, the additional strain of cooling could create all kinds of strange behaviour. Even the cable's proximity to another cable or power source (USB-cable?) with not enough cable-shielding could add unwanted electrical signal. The problem with this is, that this kind of signal would be very unpredictable and would ADD additional noise while calibrating. One thing is sure: there is no dark current in bias frames. It has to have a different source. One more thing to mention. Very subtle differences in the frames will be present. If you subtract one stack from the other and you see only very slight patterns, there is nothing to worry. It is not possible to have two 100% same frames. So maybe subtract a 0° bias from a -15° bias and measure the noise and then subtract two 0° and two 15° frames ... maybe "quite different" is only an illusion? :)
@@christoph4977 I've seen that on two cameras (and haven't tested others): a Peltier cooled 600D (internal battery powered for the camera itself) and the 1600MM (don't remember how it was powered at the time). I was comparing the stacked bias result (and also the superbias), not just the individual bias frames. The fixed pattern just looked different. I can't explain why. It took me by surprise. It doesn't make theoretical sense (especially for the internal battery powered camera).
But since then, I just take all my frames for a session at the same temp. I can with a cooled camera, and while yes, in theory it's not useful for flats and flat darks... Well I've seen that sometimes the practice begs to differ. So yeah, I err on the side of caution.
Hi Cuiv - what flat panel do you use? I am considering getting the Pegasus FlatMaster but it has some bad reviews. Thx
It's the Artesky Flat Field Generator 250
Cuiv, dark theme on NINA Pleeeeeaaassseee.
Mwahahahaaaa - I will probably revert to dark theme soon.
Thanks for the video..i have a question...if i take a 2 second exposure, with the lens covered and an even light source and get a the histogram one third to one half of the way across, is that sufficient as a flat frame or must i use a wizard? What im trying to ask is the histogram the most important part of the process?
That's perfectly enough fora flat frame! No need to use the wizard!
@@CuivTheLazyGeek brilliant..thank you 😊
I wonder, how do people take flat frames for RASA or HyperStar kind of telescopes? Personally I put scope on the table in front of big screen with white page on it, but sometime it doesn't work well for me.
Now that is exactly one of the things that is holding me back from a RASA! If I had one, I would likely go with a hood, and then my flat panel on the top of the hood. That would probably work. But yes, changing filters, flat frames, autofocus, etc. make me wary of the RASA...
@@CuivTheLazyGeek I use an SCT9.25”+Hyperstar and currently I’m taking flats by just pointing to the dawn sky when it is pristinely clear, without white T-Shirt (since I don’t change the configuration for weeks I can wait for that clear dawn and use those flats for all frames taken during other nights). Not sure if they are perfect but they did not look bad to me.. Not being able to change automatically the filters is the only drawback for me on the hyperstar, otherwise this f2.3 light bucket is an absolute joy!
I just use an AstroZap aluminum dew shield on the RASA.
Newbie here, why do I need the tee shirt? Why not put the light source in front of the camera lens and adjust the brightness?
Light source needs to be defused. Even illumination across the entire sensor.
@@TheNarrowbandChannel The light reflected off of a white wall will already be defuse so the example setup would be defused twice? Does the weave from the fabric not make its way into the image?
@@backgammonbacon That works too. Don't worry about the fabric structure. It's so close it will not be in focus. You just need to worry about armpit stains. You dirty astrophotographers. lol that part made me laugh.
Cuiv, I've read your description to this video several times and it still doesn't make sense to me. You say in the video that flats are very important, yet in your final sentence in the description, you say you only shoot lights, darks and flat darks. I'm confused.
Thanks for pointing it out I fixed it :)
@@CuivTheLazyGeek thanks 🙏
I thought flats and dark frames must match the same exposure time as your lights?
Dark frames yes, as the thermal signal is an important part of the signal that you are calibrating out (thermal + bias). Flat frames no, because calibrates out effects of the optical train - primarily dust motes and vignetting (aka light falloff), etc. These are not dependent on exposure length.
As Flanker said!
@@paths1111 Thanks for the clarification, it is greatly appreciated!!
Nice, how's your back ?
Not sure! Pain-wise it is better, but I'm anxious to get the titanium rods in my back out. My doctor never answers any of my questions, I'm considering going back to the hospital where I got the surgery in the first place...
Lazy my A$$! I might just give N.I.N.A. a try for the flats. Currently using SGP. Keep up the Lazy work. Tim
Hahaha, let's say "efficient" rather than lazy, or "selectively lazy". Didn't SGP also have a flat wizard? It's been years since I touched it though... Good luck!
Haha dirty dirty astrophotographer! As a welder i do get dirty.
Hi Cuiv, which flat panel is that? Thanks!
It's the Artesky Flat Field Generator 250mm!
So many videos lately. You must be in lock down?
Nope - but I just take videos when I can. No commute because working from home definitely helps!
Flat frames are the best worst part of this hobby. They help out so much, but they are so inconvenient.
Hahaha exactly! Completely agree!
Why are dark flats called tomato frames? And does anyone besides you call them that? :)
Sorry it was a debate amongst NINA devs and users about whether they should be called Dark Flats or Flat Darks - someone suggested the neutral term "Tomato Frames" as a compromise :D I shouldn't have mentioned it in the video, but it stuck with me!
@@CuivTheLazyGeek In "Digital SLR Astrophotography," 2nd edition, is a footnote explaining that both "dark flat" and "flat dark" make sense -- and also that neither of them makes sense.
In favor of "dark flats," they are like flats but dark. Dark is an adjective.
In favor of "flat darks," they are darks for flats (as truck tires are tires for trucks); "darks" here is a noun.
I can't remember which one I call them! I think I vacillate all the time. For my book, I made a choice, but I can't remember which one it was.
@@michael.a.covington OK you reinforce the term "tomato frames" there :D
Hi Cuiv, good to see your camera issues have been solved. Off topic, but I abandoned the NINA on a PI4 project; after I got .net 3.5 set up - which was done via running the latest updates - the thing was again extremely slow (15 minutes to login ... and my PI4 has 8GB of mem) - so not workable. But maybe some more videos like these, and I'll give in and buy a windows mini PC only to run NINA. Can you run windows 10 "headless" and connect via remote desktop on it?
g.
Windows 10 Pro has remote desktop built in but there are tons of free alternatives such as RealVNC and team viewer that work on any edition of windows
I use an "stickPC", running on Windows10, as my capture computer and connect to it from other laptop/pc or even from the ipad using Chrome Remote Desktop. I connect everything to NINA, load the sequence previously designed, and push the play bottom. Then just relax doing other stuff while monitoring from my mobile/ipad/PC how frames get capured and how the autoguiding is behaving that night. Pure fantasy! :)
On this “off topic “
I find running win10 Remote Desktop runs the smoothest when at home and I’d check in using team viewer when away on phone or laptop.
Too bad on the PI4 - it was a good and worthy project. Plus I'm sure you learned a lot!
As others have said, headless Windows 10 works, and remote access solutions like Chrome Remote Desktop also work quite well!
Are they really called tomato frames?
Sorry it was a debate amongst NINA devs and users about whether they should be called Dark Flats or Flat Darks - someone suggested the neutral term "Tomato Frames" as a compromise :D I shouldn't have mentioned it in the video, but it stuck with me!
Нихера нового я не узнал. Но диз ставить не буду.
Can't learn something new in each video!