How to take Flat Frames for Astrophotography

[@cecilepuckhaber1067]

The thing i love about you is you dont act like we know what it all means. So many youtube astrophotographers start talking about this stuff like we know. Most of us are here because we dont have a clue. So thank you so much for being detailed.

[@adowns89]

It's awesome to see how much your videos have progressed over the years. Finally getting into this hobby and I really appreciate the detail you went into in these older videos.

[@graysmith4732]

I couldn't have come across the video at a better time, I'm extremely new to astrophotography and didn't know what a flat frame was. Thank you Trevor.

[@andysuzierawlins5462]

My friend said it would help with tracked pan shots thank you for the straight forward guide

[@blackice5649]

Just getting around to viewing this video Trevor - thanks! So serious in this one!

[@nxu5107]

Thanks for this Trevor. When you do this between large time intervals, you have to start from scratch and your videos are always a good place to start.

[@andrewrobertson5504]

Always such a throwback when referencing your older videos. Its crazy how much more comfortable you are around the camera now. Good Job

[@nerrelloader4226]

I'd read online to put a t-shirt over the lens but didn't know it had to be taut. Thanks so much for this video explaining and showing the what and how. Much appreciated. Cheers!

[@MARTIN201199]

Thanks for the tips. “May the Dark Skies be with you 🖖🏼”

[@danjensen9425]

I’ve watched many of your videos many times especially the ones on Nina. I have the 294 and having issues with flats . I think now I might be able to get them right. Thank you. I wish you a 100% recovery from you injury and look forward to more awesome content.

[@toddweiler227]

Nice and straight forward. One thing I’d add is if using a CCD camera is to let it cool down to the target temperature you will be shooting that night before taking the flat. Clear and Dark Skies!

[@ChrisSmith-lk2vq]

Useful video Trevor! Thanks a lot!

[@michaelwoodcock1476]

Just had to recap on this, I brought my first DSLR not long ago and had no idea how to do flats. couldn't believe it is so easy!

[@ecaub]

Thanks for the shoutout! I haven't quite perfected taking flats with the tracing light box. It's very evenly illuminated but is a little too bright on its lowest setting. I just put a bunch of layers of t-shirts over the OTA with a big rubber band. I might try and add a potentiometer so I can dim it.

[@AstroBackyard]

+Eric Cauble You may have not perfected your flats - but your photos speak for themselves😉

[@ecaub]

Thanks, I learned it all from your vids!

[@Gouranga_Man]

Been using the Tracing pad, diffused through a sheet of white paper and the foam packing bag (also white) and had some decent results. Giving the white t-shirt method a try today for the first time. Hunted for this video specifically.

[@anzo.p]

T-shirt at daytime works well! Still don’t underestimate a Flat field generator which allows to take flats anytime, including right after lights and experimenting with flats indoors any time of day to study and learn the nature of your optical configurations

[@brod5352]

Just got finished shooting 55 subs on IC 1795 "Fishhead or Northern Bear Nebula according to google. Got my Darks and Bias all done and just waiting for the sun to come up. That's why I reviewed your video. I'm using the ZWO 294MC Pro and I need flat frames. I like the larger frame but that amp glow is quite prevalent. I wanted to use my EOS Ra but it is not supported by the ASIair yet. So I had to start my astrophotography hobby using a cooled CMOS. Darn! LOL. I love the camera but hate the amp glow. And I love the ASIair. I love the all in one feature. Now they just need to get my Canon EOS Ra supported and I'll be a happy camper. Thanks for all your videos. Your the reason I'm in this hobby. You and Dylan of course! And I'm really enjoying it. ;o)

[@davidelliott6610]

Interesting video, i should imagine its very tricky not have have the focus change if you have to wait until morning.

[@dab7963]

Trevor, I really enjoy your videos. You do such a great job for us new guys just entering the hobby. I used my Nikon DSLR last night to shoot the Eagle Nebula and am processing the files now. I think I may be hooked now ! Thanks for all you do for the hobby. Your passion is contagious.

[@chrissavaiano7906]

No need to buy anything for creating an artificial light source. Just use a white background on an ipad or computer screen. Good stuff Trevor!

[@Far-Point-Station]

Thanks Trevor perfect timing for me, I was just setting APT up for some flat frames. Love the new mount looks awesome :)

[@lassertje11]

Yes, tell us about the new mount.

[@AstroBackyard]

+Peter Goetmaekers Next video

[@jturie]

Best explanation I've seen..thank you. Wouldn't mind someday seeing updates to your processing workflow.

[@grahamb9639]

It’d be great if you could a 101 series...what different frames are used for Etc etc... I’d find that all very useful.

[@e.morrienh]

thank you! very nice videos you make!!! pls keep going ...

[@JFCalvano]

Thank you for your videos. Learning more everyday! Question about Nikon DSLRs and A (or Av) mode. Without a lens attached, how to you get the camera to work in A mode? Manual focus seems to be set only on the lens. Without a lens the camera won’t work in A mode. Thanks again.

[@Ben_Stewart]

Should work with Manual mode selected for focusing.

[@toddweiler227]

If a Canon… In the settings there is a “Release Shutter with No Lens Attached” option. That has to be enabled for the camera to take a picture. Something to look for. 👍

[@JFCalvano]

@@toddweiler227 Thank you. I’ve learned to work in M (manual) mode. 😉

[@dilipsharan8699]

Excellent video on flats

[@ChillingwithMalc]

Thanks. Nice video. Great explanation.

[@jefflucas_life]

Great introduction to making calibration files, by the way nice visually drop of your new mount and not to mention it in description. You played the pose as you've had it for a long time and it didn't need to be introduced but that's okay will learn one day what mount it is

[@kimpurser5464]

Thanks for sharing your knowledge, your vids are very helpful. As a beginner I appreciate it very much - keep it up !!!Clear skies -cheers

[@zelimirfedoran9720]

Nice CEM60! Congrats on the awesome mount!

[@dennisshields7246]

Thank you for sharing your knowledge.

[@chuknorth]

Trev, you're back with a vengeance! Excellent.

[@fredangeli5618]

Once again another great video, sometimes the most import of Astrophotograhy can Be so straight forward. Thanks for the video. Fred

[@kevinmccarty8477]

Awesome video, very helpful! I was actually just researching today how to take flat frames.

[@evemitchellanderson]

This one went way over my head

[@ryanherron1423]

Thanks man. Love these videos. Keep up the good work.

[@tonyvtc3]

Thank you Trevor, I’m just now starting to get my feet wet with calibration frames. Wish me luck. I’m looking more into the light box. But I’ll looks into the link on the light you presented in this video.

[@arturocaballero7208]

Great video. Will it be imposing to ask for mode videos on how you do other tasks such as polar alignment, and specially target finding framing and focusing?

[@gstuart0770]

Thanks for the video. It was very helpful!

[@keeplookingup911]

Nice tutorial 👍🔭

[@stefanosks6127]

..i really love your videos

[@Aubstract]

Did you get a new mount? Maybe I missed it in an earlier video, but that looks like a chinese EQ mount.

[@SIGP229TPOC]

Love the mount and tri-pier...I have the same set up! :) I also got a QHY Polemaster to make polar alignments a snap. Another option for flats is a light box used by artists, so you can do flats at any time during the day. Thanks again for your videos and clear skies!

[@gabewrsewell]

Oh no way! I was just looking around last night for how to take flats

[@aay_its_sage]

So I know you said not to remove the camera from the scope, but what If I have a narrowband clip filter in the camera? Won't the exposures be too dark?

[@boetschge]

Good to see someone else uses the Tshirt method too :-) btw nice Mount and Pillar!

[@AstroBackyard]

+boetschge Thanks!

[@Ben_Stewart]

I prefer the wet t-shirt method.

[@jerjaws]

Can you reused the whites for other pictures

[@Skibumsplace]

Thank you again. Inexpensive light box ordered from Amazon.

[@christopherlyons7613]

Is it necessary to shoot flats with the filter(s) you are using when you shoot your lights? I'm guessing no, otherwise you'd have to have a series of flats with each of the filters used. Please let me know. Thanks. Great video. Would be nice to have a cheat-sheet showing all the basic info regarding lights, darks, flats & bias frames.

[@LikeOnATree]

This video helped a lot, thanks!!

[@llamarvasquez1803]

Awww man thanks so much bro I needed this!!

[@sonicsound84]

Is there an updated video to this? I imagine technology and your technique have changed since then. 🙂

[@AstroBackyard]

I need to make a new one. thanks for the reminder!

[@sonicsound84]

@ no problem! 🙂 I look forward to it. I’m just starting out with a Sony a6400 and a sigma 24-70mm lens. It’s all I had on hand. Also, don’t leave out light panels. I’ve seen someone use an iPhone, an iPad, a sketch panel, and an astrophotography flat panel.. but each one leaves out settings or information I need to get a complete picture of how why and settings to get proper frames. 🙂

[@grantgeorgebuffett]

Great vid, but I wonder if there is any use of stacking multiple flats, or is one always enough? thanks.

[@cyberninja5652]

Not sure if what I'm doing is actually good. I move my setup inside after shooting my lights, darks en bias and put it on front of my tv on a white screen and a tshirt on.

[@HighBoss]

So to clarify, I have to have the scope at the same orientation it was in when shooting the lights, as in it needs to still be pointing at the target I was shooting? I was planning on just pointing my scope to the zenith and balancing my tablet on top of it with a pure white image on the screen - will this not be a suitable approach?

[@facarvalho]

Hi, should I make flat frames only for luminance, or should I make one for EACH filter?

[@robinlembach6294]

Thanks for the video. I read that flat frames should be taken with the same exposure that the light frames. Any clue if it worth it ?

[@walterwilmoth8390]

Robin LEMBACH not the same exposure time U need to get the adu in the correct spot and that is done by how long the exposure is The bias is removed from your flat and that is the quickest exposure you have temp will not matter as it is so short and it's just a quick dark frame only subtract that from your flat do not subtract bias from dark as you are injecting noise back into it when you do that Dark frames are same exact setting as your light

[@woldsweather]

Doesn't this mean that you can only take pics of one object per night? Or if its very dull and rainy the following day you might wait a week (here in the UK) for the bright sky.

[@ssbhide123]

I bumped up the focus ring the other day.. Can I focus at infinity again in daylight and shoot flats or not worth the effort?

[@billleonard2015]

Are you teasing the mount and tri-pier? I'd be interested in your take on the new equipment. Is it on loan for evaluation or is it yours permanently? Is it guiding well? I, too, have the CEM60 (I use it unguided) and tri-pier. Your opinions would be valued - as always.

[@nettyvoyager6336]

"ive got my t shirt on and im pointing it to the sky "sounded like you was going to turn into a superhero then and fly off ! lmao :P

[@joestafford8775]

Is the ioptron mount replacing your heq5? It looks alot beefier

[@karlsitell]

Good. Informative.

[@TeamGamingSWE]

How do I do this with my Nikon camera? the A/AV mode doesn't work if no lens is attached.

[@shaimax297]

Hi Trev, I'm trying to setup altairastro 183C on sequence generator. My Flats are coming in all black. Would you be able to guide me through, how to set up my new cam in sequence generator? Thank you

[@simonworger]

Thanks for the vid, might give flats a go now. How you liking the new mount ?

[@MajorplayLP]

My Nikon DSLR doesn't work when set to AV mode since I would need to attach a lens for it to work in AV mode

[@atafaghihimohaddess520]

good video thanks

[@astrofotoperu]

Hi Trevor, great video! I imagine that by using the flat white screen over the OTA, you don't need the white t-shirt?

[@josefalopezgracia4438]

Thank you! Liked!

[@Frizbiskit19]

I'm sad I can't do this method with my Nikon DSLR because it won't let me shoot in av mode unless I have a lens attached. It won't detect the T-rings I have for some reason

[@GaminGilmore]

Nice video! Very informative! I was thinking I could use a blank white screen on my laptop as a light source?

[@AstroBackyard]

+Hawkeye Beatbox Yes, that works too. I find it a bit awkward.. a tablet screen will work too if it's big enough!

[@BrokenPik]

ive done it, it works... 27 inch LG LCD monitor, with White T-shirt

[@icimdengelen741]

Can I use the flat frames I shot at another time for only vignetting, roughly adjusting the zoom and focus. Because I use a compact camera.

[@jarredcox6714]

i have an orion 8" f3.9 astrohraph telescope and im trying to find a somewhat affordable mount. The scope with gear weighs around 25-30 pounds any recommendations.

[@jtepsr]

what is my alternative if i go to a dark location but i can’t stay there til daybreak

[@jeffreylebowski4927]

Why does the ISO have to be the same for the flats? - Why not use the lowest ISO and do longer exposures so you have to stack less flat frames? - How does the ISO change how the sensor is illuminated???

[@SantoshKumar-wu2zb]

Is RGB filter is for DSLR camera please tell me . Or ccd camera

[@kevinhenry9981]

how do you do the dark and bias ?

[@byZenOx]

Keep it up the great work! Maybe the best Astrophotography-Channel in our galaxy ;) Greet Zeno

[@hangerbird]

How many do you need to take of the flat frames?

[@EminiMe7]

do you do this one time and then just recall the flats when needed? ss

[@qianluo6480]

You need to do it every time, because there can be dust donuts in the frame that can be masked out by the flat frame that only matches in the same shoot section. That's also why it's important to not (re)move your camera off the telescope while taking flats.

[@dankahraman354]

what about a camera lens (flats)?

[@TheAngryAstronomer]

My Nikon D5500 won't allow aperture priority so I've not got the ability to meter for correct exposure. Is there some kind of work around for this?

[@luapynneb3069]

Hi Argus You don't explain why! as normally on a D5500 you would set the dial to A (aperture priority Auto) and take your flats. But for whatever reason you can't do this > try taking a shot and then check the histogram of that image and adjust your shutter speed accordingly until the histogram is correct, some as this video say the histogram reading should be about 50% (or in the middle) others say add +2 EV and aim for a histogram reading of about 85% Hope that helps Thx paul

[@jasondonavich2758]

Do we take the same number of flats, darks, bias and lights?

[@TheflickerofMotion]

Great video man, always informative and easy to understand.... basically your a great teacher :)

[@AstroBackyard]

+TheflickerofMotion I really appreciate that dude!

[@Dennis-tf2cs]

What's the best method to use if your DSLR will not allow you to switch to AV or AP mode because it doesn't sense a lens? My Nikon D5600 will not allow this.

[@alejandrix0377]

I have the same problem, what I do is leave it in manual mode until the histogram is right in the middle. That's the solution I use but as I can't find any other one in any video or forum I just have to adapt

[@MrEzPc]

showing the new mount with flat frames before the vid on the new mount :p

[@lukesastro2380]

Awesome. Thanks a lot.

[@omulet29]

RAW or JPEG for dark,flat,bias etc???

[@michelemagagnini4235]

Love

[@gagaboul3423]

When I take a 30" exposure with my dslr, there is a 30sec exposure and then another 30sec before showing preview ..is that some calibration ..if so should I try to disable (if that doable) ?

[@grahamhgraham]

Its possible long exposure noise reduction is set to ON. Some also have a high ISO reduction feature too. I'd switch both off in the menu which means you will see the JPEG output on your back screen almost immediately. Plus, those inbuilt features dont do any better than what you can do in post processing.

[@parekh6601]

You have to switch of bracketing

[@kevinhenry9981]

and how much frame you have to shoot ?

[@tempusfugit6820]

Good video BUT not a flipping word about the new mount and pier that you clearly want us to see..!?!?!? You just wanted to keep us salivating for the next video, don't you? ;-)

[@rolandoperez8248]

I think we are going to have an equipment update video quite soon ;)

[@arringar]

I caught that too. lol

[@nettyvoyager6336]

time does fly but then it was never real it was all made up

[@peteryyz43]

What is F00?

[@fabiopignata]

thanks! but flats should have exposures longer than 1/1600 sec...

[@WorgenIce]

i dont know if i dont heard it, but how many Flat frames are nessessery to take only one? or 20 for 100 images taken? or even more?

[@JanErik1986]

There are many different opinions to this, but the most simple answer is that it depends, mainly on your ISO/gain settings and sensor temp. If shooting at higher ISO/gain/temp, each frame will have more noise to it, and so in the same way as with your light frames, you'll need more of them to even out the noise. Ideally of course you want your calibration frames to be perfect, but that's not really possible. If you shoot say 10 that might be OK, but if you shoot 20, that will increase the signal to noise by (theoretical) ~50% as compared to 10. However, if you shoot 100 you'd need to shoot 200 to get the same improvement in SNR, and so if you have 100 frames and wonder if you should take 10 more - then it's not going to make much difference. Personally for low ISO/gain i aim for at least 20-30 frames, and at high ISO/gain i often go for 50-100. When that is said, remember that all the noise that eventually remain in the calibration frames, being flat, dark or bias, will directly affect your stacked light frame. Flat and bias only take a few minutes to take, and can make all the difference, so don't save on them. Darks might be a different story though, as they can take many hours - but that's a different story... :)

[@gunnarsandberg1]

[@rolandoperez8248]

Looks like someone got an Ioptron CEM60. Congratulations on the new mount . Thanks for the video. It sure demystified this stuff. I though flats were to be taken during the astrophotograpy session like right after you took the last pic. In other places I red that you should take the flats during the session like in the middle. Does this matter at all? It will be great if you could do a video on the black and bias frames.

[@paulabrierley7979]

Great Video and nice CEM 60. Looks like you'll be able to go longer, sub wise with that baby.