After searching and searching I stumbled on this 4 year old video from you and its the best explanation out there! I really appreciate your videos and want you to know your older content is still very helpful!
On a more serious note, your videos are masterful. I've worked professionally in photography and videography for many years, and every time I watch your videos I learn something. Lots of things. Very good info and very well presented.
That is great to hear - I really wanted to make a video that goes step by step in a logical order through the whole thing, and so I am very happy it seems to be effective.
As Einstein used to say: "If you cannot explain it simply, you do not understand it well enough yourself". Your explanation is LIMPID :) On behalf of all the noobs : Thank you so much!!!
Thank you for a logical explanation which I found to be refreshing instead of the usual " I used this value and look at my images.....?" No depth and only the message" Don't question just follow what I am doing". Thank you Kurt.
Thanks for the feedback Peter! I like to understand things, so I like to transmit the relevant information that leads to the conclusion as well, as each person's situation and equipment is different! -Cuiv
I've watched a lot of videos, some are so complex you have to have a doctorate to understand, some are so simple that when you are finished you know less than when you started. As the three bears would say, this is just right. Thanks so much.
Again a great video, Cuiv. As a beginner I have treated the topics this way so far: As long as there is a wall I don't need a door. Thanks for the many doors in your videos.
Thanks for going through all this. To clarify, the Dynamic Range plot is the DR of the sensor, not your image. They are not the same. For example, in my typical dual band images of nebulae, 5 min exposures might give histograms with a main peak from say 250 to 1000 roughly. Now if I quadruple the gain, it’ll be 1000-4000. Note that the DR of my IMAGE hasn’t changed at all, it’s the same. The DR plot you show assumes that your histogram covers the full range of 1-65536, which absolutely never happens in reality. So as long as you don’t saturate pixels, you can crank up the gain and the DR of your image will not change.
Great explanation. I have watched Robins videos several times (they are very good) in the past, but just wasn't crystal clear for me about all this offset, gain stuff since I used to use a modified Canon DSLR. Now I get it!! Logical step by step and the explanation how it all works always works for me.
Excellent!! DSLRs can be so hard to use for astro (I've been through that) because of the difficulty of taking good dark frames! Good luck & clear skies!
TY for this complete, simplified and clear video explanation regarding relationships of component variables to exposure choices for image planning. Really helpful!
Quand les choses sont expliquées clairement, on les comprend facilement ! Merci Cuiv pour tout ce travail très pédagogique, il y a tant à apprendre dans ce domaine !
Thank you for explaining this. i was looking at these charts for sometime, not being exactly sure of how to interpret them. Now i can say i understand.
If I may, at 31:40, "the camera becomes more sensitive" with lower gain... it doesn't. It will have exactly the same sensitivity, however the quantization error will be less the higher the gain setting goes. Regardless, your efforts are much appreciated Cuiv, great video, keep them coming!!!
Not only you may, but please please do point out such mistakes! Thank you so much!! I am so worried about providing wrong information that comments like yours are really extremely helpful and very very welcome! You are absolutely right - the camera does not become more sensitive, although quantization error will indeed be higher there. In the end the substrates in there never gets more sensitive - it's just how we get the data back that changes everything. Thank you so much!! I will keep going, and please please never hesitate to point out mistakes!
Have fun! Note that the 294 is a temperamental beast, you absolutely should take 3 second long flat frames, and 3 second long flat darks. Take darks for your light frames too, and whatever you do DO NOT TAKE BIAS FRAMES!
Thanks for explaining it so well and the "don´t worry too much about it" attitude! That´s very much apprechiated by a beginner, worrying too much about basically everything
I am very new to imaging with the ZWO 294 MC PRO. what seemed very confusing, and i thought i'm never going to get this,now after watching your videos how you present them in an understanding point of view from you to the viewer makes things much easier to learn. I like the way you point out that you may not be the best or that you may make mistakes and to correct you if you do. To me you are doing everything right,and i know that from following your advice things can only get better for me. These videos are first class, thank you and keep up the good work
Wow - thanks for the comment. It really is one thing I strive for - helping others, especially beginners to astrophotography. This hobby can be so confusing! Soon enough, you'll see that I'm not doing everything right - and then you'll be the one making suggestions :)
thanks for this video. I will try to adjust my next shots paying attention to this explanation. I see i can improve something in my image paying attention to this details. Thanks
Excellent explanation. Thank you! I'm just starting out with my first astronomical camera (a nice simple, affordable one from Svbony), and this provided just the information I needed to understand unity gain, optimal exposure, etc. Great job!
Thanks it really helped me to set my ZWO ASI 1600. Analyzing the noise graph I will be playing with a gain of between 75 and 100, since I am in an area with high light pollution, at least for LRGB. Then I figure that a 100 to 150 gain might be more suitable for narrowband imaging. The other thing is to run a preview for each filter combination of gain, exposure and filter and look at the subs historgram as you suggested on the time exposure video.
Yet another GREAT video Cuiv, THANK YOU!! In particular, I like the level of detail you go into explaining things in lazy "layman's" terms. ;-) I often find other astro video producers don't go into nearly enough depth. I've been a subscriber for a while now, I think you've found the informational "sweet spot" for intermediate astrophotographers which I think most AP-ers fall into. Keep up the great work!
I endorse everything being said about the video- Great stuff,well explained and as others have said I,ve watched Richard Glover and listened to a pod cast etc on this subject and have an understanding but this video is like the cement between the bricks. It brings it all together. Keep on building !
Thanks for creating this video as it cleared things up a lot. I have been looking at the optimal exposure time and wondering how to use it so now I will wait for your video. I have two cameras (one a QHY 163C and a QHY 16200A CFW7 without any filters) and now I see the comparison with the ZWO 1600 and 163C as far as stats go. There is no dramatic change like the 533 so I will be staying mostly with the standard gain and playing with the exposures. Still waiting and waiting and waiting for my filters for the 16200A. Bortle 5 here.
Those are nice cameras! And a very decent Bortle level, you'll be having a lot of fun! You might be disappointed by my very cavalier approach to exposure time - but it's something that works for me! :)
Chic, you are on fire lately, and I absolutely love your videos. For the past 9 months, I’ve watched and read everything I could find about imaging with dedicated astronomy cameras, and in particular, gain/offset and how it all relates to DR and noise. I’ve never understood what I should really be doing with offset until watching this video. Your explanations of everything in this video, actually, resonate with me more than any other explanations I’ve found. So, thank you again! Also, sounds like NINA might benefit from renaming it from “optimal exposure time” to “optimal minimum exposure time”, if it’s truly calculating how much time you need in order to swamp the read noise. Maybe?
Wow, again, I'm just so happy when I read this kind of comment! Thank you! On NINA, you are right, it is indeed calculating a time that is the minimum time that the camera should expose to reliably swamp the read noise. As it is in this sense optimized (e.g. the shortest exposure time that achieves that, as per Dr Glover's videos), it probably should still be named Optimal Exposure Time - but it's good for people to know that they don't need to conform to it exactly! - Cuiv
Cuiv, Lazy Geek in Japan Cuiv, Lazy Geek in Japan I understand exactly what you mean...I’m guessing that you’re even more of a pedant than I am! 😂 I think the reason that people get confused and think that “optimal exposure time” means “max exposure time” because “optimal” just means “best”, and most people in astrophotography think “best” means “as long as possible without being swamped by light pollution”.
I shoot at 0 Gain whenever possible. On my 2600mc FW is 50k and yes there is a read noise of 3.5 e-rms. But if I want to get read noise down to that 1.5 e-rms my FW is down to 20k! I’ve cut my full well by more then 1/2 to save a handful of electrons in reading noise. So I choose to use the full well depth, but I also have very dark clear skies and I’m willing to wait longer for exposures. In other words I want the full range of the 16-bit camera. With gain you’re compressing your image. That’s ‘sort-a’ like the old vinyl records that had compressed audio. Then CDs came out and one got the full dynamic range of the music. Big difference. But if one has to run a light pollution filter and have invested reasonably in mount and auto-guider system they have whatever time them have to work with and use gain as needed.
Exactly. In the end this is about whatever compromise the user is willing to make. The thing with read noise is that you have to pay the read noise tax with each and every exposure, and the optimal exposure time is proportional to the square of that read noise! It is not inconsequential. And DR can be recovered to some extent via stacking. So I personally prefer to get the gain up to have lowered my read noise so I can keep my exposures short. This is doubly true with narrowband - I'd have to take extremely long exposures if I lowered my gain, and in the end this is what Dr Glover recommends as well - but in the end it's up to each user's personal preferences! As for the full dynamic range of the music... unfortunately while CDs can keep that dynamic range, the loudness wars go against that... en.wikipedia.org/wiki/Loudness_war . Good luck & Clear Skies!
Genki Desu Cuiv, You are breaking down all the technological jargon into small bite sized chunks that are easy to digest. Long may it continue and Arigato Gosai Masu many times over. I still don’t really understand the concept of sampling and Rayleigh criterion pixel size to aperture etc That’s me being a bit dim and not putting enough time to understand it. What is worse is that I have a degree in Maths and physics. What that has helped me is in my job as an IT person. But Astrophotography is my first passion followed by Liverpool Football Club.hmmm. Take care and many many thanks.
Don't worry too much - I'm not on top of sampling either, but there are some good tools to estimate that. I'll cover FOV and pixel size (and to some extent sampling) in a later video, I think!
RE: 100 vs 101 gain, I get it. All it takes is one developer somewhere in any of your apps to have coded it as “through 100” vs “to 100”...and it’s an easy mistake for one to make! I’m going to always use 101 gain with my 2600 from now on (it has that same jump at 100 that your 533 does). I’ve thought this ever since you mentioned that you use gain 101, several videos. Thank you! 😊
Cuiv, I love the 2600, but I came directly from a Canon 5DmkII, so I don’t have a good reference/comparison to other cooled/dedicated astro cams. On paper, it’s very similar to your 533, though, as I’m sure you know! 😊
Hi Cuiv, I find your videos both interesting and entertaining. You’ve got the knack! Congratulations and thank you for your thoughtful and helpful insights.
We can always gather more signal, although our goal is to gather SNR! Each time you want to gather twice more SNR, you need to quadruple the total integration time - when to stop is purely up to each imager, there is no rule there!
Cuiv…wow!! I will need to watch this episode at least ten more times to fully understand most of what you are teaching us!! My question is…as you increase gain (thereby shortening exposure time), aren’t you increasing RN?
that was great, I think where a lot of people (me included) go wrong (especially photographers) is we think of gain as a sort of ISO, which makes it difficult to get your head around then as the lower the ISO the less noise. Using the 1600 if I put my gain at 139 take an image then put my gain at say 30 or 50 the image is a lot less grainy so (in my case i cant speak for anyone else) You cant help then by having that stuck in you head that reducing gain makes for a cleaner image. Hope i make sense.
Glad to hear that! Now there is a very important distinction to make: noise versus signal to noise ratio - for the same total stack time, stacks at different gains show remarkably similar levels of SNR (which is what we are after). So something to keep in mind as well!
Excellent info👌🏼 Even I wondered why my optimal exposure time was so low but I ended up thinking it was more like minimum exposure which you just confirmed. Thanks Cuiv👍🏼
That's pretty much it! I think we tend to be a bit perfectionist in this hobby, which can really get in the way of enjoyment. But yes, if you don't go overboard while going a bit beyond the optimal exposure time, you should be fine! There's another video in this playlist as well.
Ray?! I love your channel, thanks for dropping by! Awesome job on M51 with that C14 (also, green with envy - even though I know my seeing doesn't justify a C14!). Also F/2 scopes..... :D so good!
Thank you again Cuiv - I have the ASI 1600, but the product page is no longer accessible from ZWO's website - Do you have a link to the graphical data you displayed regarding Optimal GAIN with minimal noise? I have searched but can't find anything
Thank you Cuiv, filled in alot much appreciated - took early advice develop my AP in broadband first (have ASI294C Pro) good pixel size for both my APO's ( F5 to F7 with reducer). Am learning N.I.N.A, love it over SGP, use Pegasus UPB2 & Focuser 2 etc. ☺️🔭
Glad it helped! That sounds like a killer combo - the ASI294MC Pro is such a good camera if you're not in a super light polluted area! It could give you trouble with flats (I recommend taking flats above the gain "jump", so at 121, or I've personally seen issues). Enjoy NINA and clear skies!
I am starting to wonder if it is looking up at sky objects or all the cool gadgets and telescope equipment that is the fun stuff to do astronomy? 😎 Thank you.
Great video - I also add 1 to the Gain I use based on supplier graphs. In my case QHY600 where their website says Gain 0-55 uses LGC and Gain 55-100 uses HGC :) . I use Gain 57 just to be sure as they don't seem to understand boolean algebra. (I have written to them to get it corrected).
Cuiv, I just purchased a new ZWO ASI2600MC Pro and I've got a problem that I can't seem to figure out. I have been using my ASI 294MC pro with NINA and it's been working just fine. But the 2600MC Pro connects to NINA as normal. And it starts the exposure as normal. I do a 5 second test sub and when it's time to upload the image to NINA it fails. I get multiple, what I think are, ASCOM errors. It doesn't matter how long or short the exposure is, it always fails. And it does it on my PC and it does the same thing on my laptop. So two different computers exhibiting the same issue. BUT..... when I hook it up to my ASI Air Pro, it works like a champ! So it's not the camera. I'm wondering if it's a Windows 10 issue. Or maybe a ZWO Driver issue? I've got a ticket in with ZWO but I just sent it to them. And they are on holiday right at the moment. But your so familiar with NINA I thought maybe you may have seen this phenomena? Any help anyone can offer would be appreciated. Oh... on another note, why does my 294MC pro gain go so much higher than my 2600MC Pro? I typically use 135 as my gain on my 294MC Pro but the max gain on the 2600MC Pro is just 100. Which is it's unity gain. So I'm curious why so much different. But I really need help on why it won't upload the image. That has me really stumped.
Just found your channel - I am impressed! I have just started using the 533 and was examining the gain and read noise graphs on the ZWO website. It may be my wishful thinking, but I think there is a little squiggle in both that show that for instance the read noise cliff edge is at 99, and down the bottom of the transition at 100. Perhaps we should double check with ZWO but your paranoia may not be justified!
Thank you! You're absolutely right - the wiggle shows that we should be in the high gain conversion mode at exactly gain 100! But paranoia is not logical :) I fear any programming error for example - but you're right, it is 99.9% sure that 100 is perfectly fine :)
' extremely simplified ' he says : ' ) My head is spinning from all this information, well explained Cuiv, gonna have to come back to this video a couple more times!
What a master class !!!! Thank you so much for your time and great explanations of these interesting detector concepts. I feel I've obtained a better understanding on gain and offset. All the best, clear skies and shine on from the "Cluster One Observatory" in Chile.
@@CuivTheLazyGeek Thanks for your reply. And yes, southern skies from Chile are just amazing. I work as observing specialist at the European Southern Observatory (ESO) and every time I starred at the night sky from the top of the mountains feels like really getting closer to the sky in every sense. Cheers from Chile!
old vid but still nice to see. since you said it your self, I never do the optimal exposure only use that as a minimum value have you ever tried to doing a video and making your self use that number the calculator gives you just to be sure the advantages of optimal is not worth the time it take to stack?
Hello, tell me how quickly the camera should be defrosted after cooling to minus 10 degrees? After all, with a sharp change in temperature, it can leak? What will lead to its breakdown. Maybe 2-3 degrees per minute or 5 degrees per minute? How right?
Great Video!! Two thumps up 👍👍 Why do leave the histogramm in the first third? I shoot with a DSLR and tried always to follow the ETTR rule (keep the historgramm within 2/3). Could you please say something to this concept? Thank you and keep up the excellent work. Stay healthy and CS.
Yeah, the ETTR is a very common method for DSLRs to capture wife field Milky Way pictures, and works well for single exposures (not stacks!) - you do saturate the star cores to some extent, but you don't care! For standard astrophoto, where you can stack to increase SNR, you don't have to sacrifice star cores - you can go with ETTL. In the end these are two capture methods for different purposes and different processing techniques. Same to you, Clear Skies and Health! :)
Super usefull video! Thanks for explaining this so well and taking your time to do it! Unity gain for my 1600 it is for nebula season, and pleiades and orion will get 75-100 :)
Interestingly you can only expose up to 33 minutes with the 2600MC Pro OSC CMOS camera (they must have software limited the exposure time?) whereas for my Trius M26C OSC CCD cameras I have taken exposures up to 1-hour - no problem.
At 8:26 , Do you mean 1 electron to change to next ADU or it should be 100 electron to change to next ADU? Iasked this because in the Graph the "e" is in minus so its in the denominator , Also i saw in all graphs of ZWO cameras the Value of Gain is taken at 1 so it must not mean 1 electron for all these cameras.
I'm have a ASI1600MMC too, and I look for my expose time, that I don't get much white areas in the pictures, so that I get only a few of outburned stars, so I make I relation between expsore time and full well capacity.
Excellent Cuiv. I'm trying to learn as much as possible, before I take the step from DSLR to dedicated astro camera. Your video was like a giant step! Lots to learn and understand. Thank you for making it a little less daunting. Prior to watching, I was of the mind to get an ASI 533 MC PRO or ASI 2600 MC PRO, utilizing a filter drawer, with the Optolong L-extreme. Based on my gear, (WO GT 81 with WO .8 FF/FR), these sensor sizes would work reasonably well. Another question I have relates to ZWO documentation, which states for the ASI 2600 to use either a 0 gain setting or 100 gain setting. The 100 I understand after watching your detailed explanations, however, I don't get why they would say 0 gain. Can you explain that for me? Thanks for running one of the best channels on RUclips!
Just last week I received a 294mc pro, this video was incredibly helpful for understanding the terminology that comes with these astro cams! Quality content again! Keep at it! :)
Thank you - and good to hear this is helpful! The 294MC Pro itself begs to be used at gain 120 (or 121 if you're superstitious like me), and it is extremely sensitive. I hope you'll enjoy it!
Hi Quiv! Unfortunately I don’t have the time to watch this full video rn so I’m not sure if you mentioned this, but I just started using nina and my sub scores when stacked in Deep Sky Stacker were extremely low. Since I’m using a DSLR and I didn’t see an ISO setting option, I set my gain to 1600. Is this incorrect? My scores typically range from 200-1000 and I was receiving 5-20...
Hello there! Mmmmh, I am not sure actually - I don't really know how DSS computes sub scores, what camera you use, etc. I think the best would be to check in the beginners corner channel of the NINA Discord discord.gg/rWRbVbw . The devs there would be able to help you far better than I can! Good luck & Clear skies!
After searching and searching I stumbled on this 4 year old video from you and its the best explanation out there! I really appreciate your videos and want you to know your older content is still very helpful!
That's awesome to hear! I have a somewhat updated version somewhere - and also for flat frames as well!
On a more serious note, your videos are masterful. I've worked professionally in photography and videography for many years, and every time I watch your videos I learn something. Lots of things. Very good info and very well presented.
Two years later, and this content is still golden! Thanks for teaching me these concepts - super useful for a new astrophotographer.
Thanks John! Happy to see it's still useful!
Best explanation I have ever seen. Just makes more sense now. Can't wait for your next video.
That is great to hear - I really wanted to make a video that goes step by step in a logical order through the whole thing, and so I am very happy it seems to be effective.
As Einstein used to say: "If you cannot explain it simply, you do not understand it well enough yourself". Your explanation is LIMPID :) On behalf of all the noobs : Thank you so much!!!
I hope he didnt say that in response to entanglement :)
Thank you for a logical explanation which I found to be refreshing instead of the usual " I used this value and look at my images.....?" No depth and only the message" Don't question just follow what I am doing". Thank you Kurt.
Thanks for the feedback Peter! I like to understand things, so I like to transmit the relevant information that leads to the conclusion as well, as each person's situation and equipment is different!
-Cuiv
Thanks Cuiv, I just bought a 294MM Pro and couldn't get my head around all these values by looking at forum posts. You explained everything perfectly!
I've watched a lot of videos, some are so complex you have to have a doctorate to understand, some are so simple that when you are finished you know less than when you started. As the three bears would say, this is just right. Thanks so much.
I can’t tell you how much I appreciate this and all of your NiNa videos, thank you so much 🙏
Thanks for this feedback! It is extremely encouraging!
Again a great video, Cuiv. As a beginner I have treated the topics this way so far: As long as there is a wall I don't need a door. Thanks for the many doors in your videos.
Glad that this is helpful! I love revealing hidden doors :)
Thanks for going through all this. To clarify, the Dynamic Range plot is the DR of the sensor, not your image. They are not the same. For example, in my typical dual band images of nebulae, 5 min exposures might give histograms with a main peak from say 250 to 1000 roughly. Now if I quadruple the gain, it’ll be 1000-4000. Note that the DR of my IMAGE hasn’t changed at all, it’s the same. The DR plot you show assumes that your histogram covers the full range of 1-65536, which absolutely never happens in reality. So as long as you don’t saturate pixels, you can crank up the gain and the DR of your image will not change.
A very informative comment, thank you.
Great explanation. I have watched Robins videos several times (they are very good) in the past, but just wasn't crystal clear for me about all this offset, gain stuff since I used to use a modified Canon DSLR. Now I get it!! Logical step by step and the explanation how it all works always works for me.
Excellent!! DSLRs can be so hard to use for astro (I've been through that) because of the difficulty of taking good dark frames! Good luck & clear skies!
This clears up a lot of question I have about dedicated astro cameras.
I do miss your videos since you took your break. Hope you come back soon . You're quite the character. 👍
That's probably by far the best video on that topic I've ever seen, thanks for that.
Thank you! Glad it was useful!
TY for this complete, simplified and clear video explanation regarding relationships of component variables to exposure choices for image planning. Really helpful!
This is probably the best video explaining this I’ve ever seen.
👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻
I proudly wear your T-shirt
Quand les choses sont expliquées clairement, on les comprend facilement ! Merci Cuiv pour tout ce travail très pédagogique, il y a tant à apprendre dans ce domaine !
Just enough explanation to really help me along! Thanks, Cuiv! 👍
Happy to help!
Thank you for explaining this. i was looking at these charts for sometime, not being exactly sure of how to interpret them. Now i can say i understand.
Awesome video Cuiv! This is the best explanation of gain and read noise I've come across on youtube.
Thank you! That was the objective, and I'm glad it seems to be helping a lot of people!
If I may, at 31:40, "the camera becomes more sensitive" with lower gain... it doesn't. It will have exactly the same sensitivity, however the quantization error will be less the higher the gain setting goes. Regardless, your efforts are much appreciated Cuiv, great video, keep them coming!!!
Not only you may, but please please do point out such mistakes! Thank you so much!! I am so worried about providing wrong information that comments like yours are really extremely helpful and very very welcome! You are absolutely right - the camera does not become more sensitive, although quantization error will indeed be higher there. In the end the substrates in there never gets more sensitive - it's just how we get the data back that changes everything. Thank you so much!! I will keep going, and please please never hesitate to point out mistakes!
Thanks. This helps make sense of those graphs for my new ASI294MC Pro.
Happy to help!
Got a second hand 294MC Pro which I can't wait for the life of me to try. Thanks for the video, it really helps understanding all the settings!!
Have fun! Note that the 294 is a temperamental beast, you absolutely should take 3 second long flat frames, and 3 second long flat darks. Take darks for your light frames too, and whatever you do DO NOT TAKE BIAS FRAMES!
@@CuivTheLazyGeekThanks for the advice!!!. I'll do it that way then :)
Nice one, and thank you. Just moving from DSLR to ASI1600MM so very good explanation. Just got to figure it in APT now.
Well done! you seem to be a natural at making the complex simple to understand.
Thank you! I try :)
thank you so much for working your way through the camera data and charts in ZWO website; very very helpful.
Thanks for explaining it so well and the "don´t worry too much about it" attitude! That´s very much apprechiated by a beginner, worrying too much about basically everything
I am very new to imaging with the ZWO 294 MC PRO. what seemed very confusing, and i thought i'm never going to get this,now after watching your videos how you present them in an understanding point of view from you to the viewer makes things much easier to learn. I like the way you point out that you may not be the best or that you may make mistakes and to correct you if you do. To me you are doing everything right,and i know that from following your advice things can only get better for me. These videos are first class, thank you and keep up the good work
Wow - thanks for the comment. It really is one thing I strive for - helping others, especially beginners to astrophotography. This hobby can be so confusing! Soon enough, you'll see that I'm not doing everything right - and then you'll be the one making suggestions :)
thanks for this video. I will try to adjust my next shots paying attention to this explanation. I see i can improve something in my image paying attention to this details. Thanks
Wow! So well explained! Thanks so much for this master class!
Excellent explanation. Thank you! I'm just starting out with my first astronomical camera (a nice simple, affordable one from Svbony), and this provided just the information I needed to understand unity gain, optimal exposure, etc. Great job!
Thanks it really helped me to set my ZWO ASI 1600. Analyzing the noise graph I will be playing with a gain of between 75 and 100, since I am in an area with high light pollution, at least for LRGB. Then I figure that a 100 to 150 gain might be more suitable for narrowband imaging. The other thing is to run a preview for each filter combination of gain, exposure and filter and look at the subs historgram as you suggested on the time exposure video.
Many thanks for these perfect explanations in simple words! I'm a beginner... and feel much more comfortable now! Kind regards, Markus.
Glad it is useful! Many more videos like this on the channel, feel free to explore ;)
Yet another GREAT video Cuiv, THANK YOU!! In particular, I like the level of detail you go into explaining things in lazy "layman's" terms. ;-) I often find other astro video producers don't go into nearly enough depth. I've been a subscriber for a while now, I think you've found the informational "sweet spot" for intermediate astrophotographers which I think most AP-ers fall into. Keep up the great work!
Thanks for that feedback Thomas! I try hard to get the right balance, and it can be really difficult, so this is great feedback!
I endorse everything being said about the video- Great stuff,well explained and as others have said I,ve watched Richard Glover and listened to a pod cast etc on this subject and have an understanding but this video is like the cement between the bricks. It brings it all together.
Keep on building !
Will keep building, thanks for the feedback! There is so much ground to cover, so it's keeping me very busy :)
Thanks for creating this video as it cleared things up a lot. I have been looking at the optimal exposure time and wondering how to use it so now I will wait for your video. I have two cameras (one a QHY 163C and a QHY 16200A CFW7 without any filters) and now I see the comparison with the ZWO 1600 and 163C as far as stats go. There is no dramatic change like the 533 so I will be staying mostly with the standard gain and playing with the exposures. Still waiting and waiting and waiting for my filters for the 16200A. Bortle 5 here.
Those are nice cameras! And a very decent Bortle level, you'll be having a lot of fun! You might be disappointed by my very cavalier approach to exposure time - but it's something that works for me! :)
Chic, you are on fire lately, and I absolutely love your videos. For the past 9 months, I’ve watched and read everything I could find about imaging with dedicated astronomy cameras, and in particular, gain/offset and how it all relates to DR and noise. I’ve never understood what I should really be doing with offset until watching this video. Your explanations of everything in this video, actually, resonate with me more than any other explanations I’ve found. So, thank you again! Also, sounds like NINA might benefit from renaming it from “optimal exposure time” to “optimal minimum exposure time”, if it’s truly calculating how much time you need in order to swamp the read noise. Maybe?
Wow, again, I'm just so happy when I read this kind of comment! Thank you! On NINA, you are right, it is indeed calculating a time that is the minimum time that the camera should expose to reliably swamp the read noise. As it is in this sense optimized (e.g. the shortest exposure time that achieves that, as per Dr Glover's videos), it probably should still be named Optimal Exposure Time - but it's good for people to know that they don't need to conform to it exactly!
- Cuiv
Cuiv, Lazy Geek in Japan Cuiv, Lazy Geek in Japan I understand exactly what you mean...I’m guessing that you’re even more of a pedant than I am! 😂 I think the reason that people get confused and think that “optimal exposure time” means “max exposure time” because “optimal” just means “best”, and most people in astrophotography think “best” means “as long as possible without being swamped by light pollution”.
I shoot at 0 Gain whenever possible. On my 2600mc FW is 50k and yes there is a read noise of 3.5 e-rms. But if I want to get read noise down to that 1.5 e-rms my FW is down to 20k! I’ve cut my full well by more then 1/2 to save a handful of electrons in reading noise. So I choose to use the full well depth, but I also have very dark clear skies and I’m willing to wait longer for exposures. In other words I want the full range of the 16-bit camera. With gain you’re compressing your image. That’s ‘sort-a’ like the old vinyl records that had compressed audio. Then CDs came out and one got the full dynamic range of the music. Big difference. But if one has to run a light pollution filter and have invested reasonably in mount and auto-guider system they have whatever time them have to work with and use gain as needed.
Exactly. In the end this is about whatever compromise the user is willing to make. The thing with read noise is that you have to pay the read noise tax with each and every exposure, and the optimal exposure time is proportional to the square of that read noise! It is not inconsequential. And DR can be recovered to some extent via stacking. So I personally prefer to get the gain up to have lowered my read noise so I can keep my exposures short. This is doubly true with narrowband - I'd have to take extremely long exposures if I lowered my gain, and in the end this is what Dr Glover recommends as well - but in the end it's up to each user's personal preferences! As for the full dynamic range of the music... unfortunately while CDs can keep that dynamic range, the loudness wars go against that... en.wikipedia.org/wiki/Loudness_war . Good luck & Clear Skies!
Thanks very much for explaining ADUs! I've never gotten a decent explanation before. (I'm a total beginner.)
Glad it helped! Good luck with the hobby :)
Thank you so much for your well prepared explanation.
You are quite welcome! Glad you liked it.
"...all about swamping the read noise...". Too funny. Thanks for the informative and fun videos
Genki Desu Cuiv, You are breaking down all the technological jargon into small bite sized chunks that are easy to digest. Long may it continue and Arigato Gosai Masu many times over. I still don’t really understand the concept of sampling and Rayleigh criterion pixel size to aperture etc That’s me being a bit dim and not putting enough time to understand it. What is worse is that I have a degree in Maths and physics. What that has helped me is in my job as an IT person. But Astrophotography is my first passion followed by Liverpool Football Club.hmmm. Take care and many many thanks.
Don't worry too much - I'm not on top of sampling either, but there are some good tools to estimate that. I'll cover FOV and pixel size (and to some extent sampling) in a later video, I think!
Always learn something when I watch your videos. Thanks!
Hi Cuiv, thank you very much for this great video. I finally understand how it works! Looking forward to your next video...
My pleasure! Glad it helped!
Great video as usual Cuiv! None of this made sense to me until you made it so simple to understand.
Glad it helps! It was so hard for me to understand those concepts as well!
RE: 100 vs 101 gain, I get it. All it takes is one developer somewhere in any of your apps to have coded it as “through 100” vs “to 100”...and it’s an easy mistake for one to make! I’m going to always use 101 gain with my 2600 from now on (it has that same jump at 100 that your 533 does). I’ve thought this ever since you mentioned that you use gain 101, several videos. Thank you! 😊
Hahaha, exactly! I mean I'm sure it's OK at 100 but.... :D How do you like your 2600?
Cuiv, I love the 2600, but I came directly from a Canon 5DmkII, so I don’t have a good reference/comparison to other cooled/dedicated astro cams. On paper, it’s very similar to your 533, though, as I’m sure you know! 😊
Hi Cuiv, I find your videos both interesting and entertaining. You’ve got the knack! Congratulations and thank you for your thoughtful and helpful insights.
Thanks, this is well explained. Nice to see you using the asi533.
Glad it's helpful! I hope you'll get great results with the 533!
Cuiv, love you videos. I have question for you. At what point do we say we have enough data and continuing to image won't provide anymore Signal?
We can always gather more signal, although our goal is to gather SNR! Each time you want to gather twice more SNR, you need to quadruple the total integration time - when to stop is purely up to each imager, there is no rule there!
Thank you, I understand a lot more now
My pleasure, glad it is useful!
Thank you for the explanation, best I have seen so far!
My pleasure, glad it helped!
Great info and very well explained Quiv 👍🏼👍🏼
I have always wondered what these graphs meant! Thank you SO MUCH! Your videos are so helpful.
My pleasure!
Muy buena y clara explicación, un capo total.
Cuiv…wow!! I will need to watch this episode at least ten more times to fully understand most of what you are teaching us!!
My question is…as you increase gain (thereby shortening exposure time), aren’t you increasing RN?
that was great, I think where a lot of people (me included) go wrong (especially photographers) is we think of gain as a sort of ISO, which makes it difficult to get your head around then as the lower the ISO the less noise. Using the 1600 if I put my gain at 139 take an image then put my gain at say 30 or 50 the image is a lot less grainy so (in my case i cant speak for anyone else) You cant help then by having that stuck in you head that reducing gain makes for a cleaner image. Hope i make sense.
Glad to hear that! Now there is a very important distinction to make: noise versus signal to noise ratio - for the same total stack time, stacks at different gains show remarkably similar levels of SNR (which is what we are after). So something to keep in mind as well!
Excellent info👌🏼 Even I wondered why my optimal exposure time was so low but I ended up thinking it was more like minimum exposure which you just confirmed. Thanks Cuiv👍🏼
That's pretty much it! I think we tend to be a bit perfectionist in this hobby, which can really get in the way of enjoyment. But yes, if you don't go overboard while going a bit beyond the optimal exposure time, you should be fine! There's another video in this playlist as well.
I use mainly HDR with F/2 scopes. Keeps it simple, Great presentation!
Ray?! I love your channel, thanks for dropping by! Awesome job on M51 with that C14 (also, green with envy - even though I know my seeing doesn't justify a C14!). Also F/2 scopes..... :D so good!
@@CuivTheLazyGeek Thanks Cuiv!
Thank you again Cuiv - I have the ASI 1600, but the product page is no longer accessible from ZWO's website - Do you have a link to the graphical data you displayed regarding Optimal GAIN with minimal noise? I have searched but can't find anything
It's the same characteristics as the Pro, so you can use that: astronomy-imaging-camera.com/product/asi1600mm-cool
@@CuivTheLazyGeek Thanks - I shou have said it was a 1600mm Pro - I set it to 140 (139 plus 1) I couldn't however set the Offset in NINA
Thank you Cuiv, filled in alot much appreciated - took early advice develop my AP in broadband first (have ASI294C Pro) good pixel size for both my APO's ( F5 to F7 with reducer). Am learning N.I.N.A, love it over SGP, use Pegasus UPB2 & Focuser 2 etc. ☺️🔭
Glad it helped! That sounds like a killer combo - the ASI294MC Pro is such a good camera if you're not in a super light polluted area! It could give you trouble with flats (I recommend taking flats above the gain "jump", so at 121, or I've personally seen issues). Enjoy NINA and clear skies!
You’re a fantastic teacher. Thank you (from a noob).
I am starting to wonder if it is looking up at sky objects or all the cool gadgets and telescope equipment that is the fun stuff to do astronomy? 😎 Thank you.
Great video - I also add 1 to the Gain I use based on supplier graphs. In my case QHY600 where their website says Gain 0-55 uses LGC and Gain 55-100 uses HGC :) . I use Gain 57 just to be sure as they don't seem to understand boolean algebra. (I have written to them to get it corrected).
Well presented. Enjoying the videos.
Thank you!
Cuiv, I just purchased a new ZWO ASI2600MC Pro and I've got a problem that I can't seem to figure out. I have been using my ASI 294MC pro with NINA and it's been working just fine. But the 2600MC Pro connects to NINA as normal. And it starts the exposure as normal. I do a 5 second test sub and when it's time to upload the image to NINA it fails. I get multiple, what I think are, ASCOM errors. It doesn't matter how long or short the exposure is, it always fails. And it does it on my PC and it does the same thing on my laptop. So two different computers exhibiting the same issue. BUT..... when I hook it up to my ASI Air Pro, it works like a champ! So it's not the camera. I'm wondering if it's a Windows 10 issue. Or maybe a ZWO Driver issue? I've got a ticket in with ZWO but I just sent it to them. And they are on holiday right at the moment. But your so familiar with NINA I thought maybe you may have seen this phenomena? Any help anyone can offer would be appreciated. Oh... on another note, why does my 294MC pro gain go so much higher than my 2600MC Pro? I typically use 135 as my gain on my 294MC Pro but the max gain on the 2600MC Pro is just 100. Which is it's unity gain. So I'm curious why so much different. But I really need help on why it won't upload the image. That has me really stumped.
Just found your channel - I am impressed! I have just started using the 533 and was examining the gain and read noise graphs on the ZWO website. It may be my wishful thinking, but I think there is a little squiggle in both that show that for instance the read noise cliff edge is at 99, and down the bottom of the transition at 100. Perhaps we should double check with ZWO but your paranoia may not be justified!
Thank you! You're absolutely right - the wiggle shows that we should be in the high gain conversion mode at exactly gain 100! But paranoia is not logical :) I fear any programming error for example - but you're right, it is 99.9% sure that 100 is perfectly fine :)
' extremely simplified ' he says : ' ) My head is spinning from all this information, well explained Cuiv, gonna have to come back to this video a couple more times!
What a master class !!!! Thank you so much for your time and great explanations of these interesting detector concepts. I feel I've obtained a better understanding on gain and offset.
All the best, clear skies and shine on from the "Cluster One Observatory" in Chile.
Hi Felipe, glad this was useful! And wow... Chile. Darn, you have some of the best night skies on Earth, I am so jealous!
@@CuivTheLazyGeek Thanks for your reply. And yes, southern skies from Chile are just amazing. I work as observing specialist at the European Southern Observatory (ESO) and every time I starred at the night sky from the top of the mountains feels like really getting closer to the sky in every sense. Cheers from Chile!
old vid but still nice to see.
since you said it your self, I never do the optimal exposure only use that as a minimum value have you ever tried to doing a video and making your self use that number the calculator gives you just to be sure the advantages of optimal is not worth the time it take to stack?
Best explanation on you tube.
Thank you Andy! Glad it was useful!
Hello, tell me how quickly the camera should be defrosted after cooling to minus 10 degrees? After all, with a sharp change in temperature, it can leak? What will lead to its breakdown. Maybe 2-3 degrees per minute or 5 degrees per minute? How right?
Amazing explanation, very clear. good job!
Thank you! Glad it helped!
Finally I get it. Thank you for this excellent explanation.
I am very, very glad it helped!!
Great Video!! Two thumps up 👍👍 Why do leave the histogramm in the first third? I shoot with a DSLR and tried always to follow the ETTR rule (keep the historgramm within 2/3). Could you please say something to this concept? Thank you and keep up the excellent work. Stay healthy and CS.
Yeah, the ETTR is a very common method for DSLRs to capture wife field Milky Way pictures, and works well for single exposures (not stacks!) - you do saturate the star cores to some extent, but you don't care! For standard astrophoto, where you can stack to increase SNR, you don't have to sacrifice star cores - you can go with ETTL. In the end these are two capture methods for different purposes and different processing techniques. Same to you, Clear Skies and Health! :)
this video answered sooo many of my questions, thanks so much !
Awesome, and glad this helped!!
Thanks so much. There's a lot to be gained from your videos! :-)
This is a bunch of excellent explanations! Thanks!
As usual. Great work!!!! Very Happy to have find you on internet :-)
Thank you! Glad you found me ;)
Well, that explained it easier than others have, mentioning no names
Thank you so much for explanation and I love the great quality of your videos!
Really interesting and well explained. Thank you!!
My pleasure Lucas! Glad it was helpful!
Super usefull video! Thanks for explaining this so well and taking your time to do it! Unity gain for my 1600 it is for nebula season, and pleiades and orion will get 75-100 :)
Glad it was helpful! Good luck with your imaging & clear skies!
Interestingly you can only expose up to 33 minutes with the 2600MC Pro OSC CMOS camera (they must have software limited the exposure time?) whereas for my Trius M26C OSC CCD cameras I have taken exposures up to 1-hour - no problem.
I think it needs to be renamed from Optimal exposure time to minimum exposure time because it doesn't take into account target brightness
Are you using the native driver or the ascom driver for your 533? If you are using the native driver what are you setting your offset at?
Native driver - and I'm using the offset that is what is set in the ASCOM driver, so 70!
At 8:26 , Do you mean 1 electron to change to next ADU or it should be 100 electron to change to next ADU? Iasked this because in the Graph the "e" is in minus so its in the denominator , Also i saw in all graphs of ZWO cameras the Value of Gain is taken at 1 so it must not mean 1 electron for all these cameras.
I'm have a ASI1600MMC too, and I look for my expose time, that I don't get much white areas in the pictures, so that I get only a few of outburned stars, so I make I relation between expsore time and full well capacity.
Yep, that's the right approach - whatever works for you is the right choice. Gain is a tool that can be used!
Great explanation Cuiv. Thanks.
Glad it helped!
This is a definitive work. Thank you.
Excellent Cuiv. I'm trying to learn as much as possible, before I take the step from DSLR to dedicated astro camera. Your video was like a giant step! Lots to learn and understand. Thank you for making it a little less daunting. Prior to watching, I was of the mind to get an ASI 533 MC PRO or ASI 2600 MC PRO, utilizing a filter drawer, with the Optolong L-extreme. Based on my gear, (WO GT 81 with WO .8 FF/FR), these sensor sizes would work reasonably well. Another question I have relates to ZWO documentation, which states for the ASI 2600 to use either a 0 gain setting or 100 gain setting. The 100 I understand after watching your detailed explanations, however, I don't get why they would say 0 gain. Can you explain that for me? Thanks for running one of the best channels on RUclips!
I think the 0 gain has a marginally higher dynamic range than 100, which is likely the reason!
Just last week I received a 294mc pro, this video was incredibly helpful for understanding the terminology that comes with these astro cams! Quality content again! Keep at it! :)
Thank you - and good to hear this is helpful! The 294MC Pro itself begs to be used at gain 120 (or 121 if you're superstitious like me), and it is extremely sensitive. I hope you'll enjoy it!
@@CuivTheLazyGeek is that with HGC on or off
Thanks for going over this. Looking forward to the next vid. Keep it up!
Thanks!
Very well explained. Keep up the good work!
Hi Quiv! Unfortunately I don’t have the time to watch this full video rn so I’m not sure if you mentioned this, but I just started using nina and my sub scores when stacked in Deep Sky Stacker were extremely low. Since I’m using a DSLR and I didn’t see an ISO setting option, I set my gain to 1600. Is this incorrect? My scores typically range from 200-1000 and I was receiving 5-20...
Hello there! Mmmmh, I am not sure actually - I don't really know how DSS computes sub scores, what camera you use, etc. I think the best would be to check in the beginners corner channel of the NINA Discord discord.gg/rWRbVbw . The devs there would be able to help you far better than I can! Good luck & Clear skies!
Cuiv, The Lazy Geek awesome thanks! And the camera is a Nikon D5200
Great Video, I only own these 2 cameras. It's like a personal instruction video.
Extremely Beneficial for me. Thank you Cuiv
My pleasure, glad it was useful!
Thanks Cuiv! Looking forward to watching this :)
Thanks!
Thx for this. Really easy to understand. Keep up the great content
Glad it was useful! Thanks for the feedback :-)
Very nice presentation and very informative! Subscribed!
Thank you and welcome to the channel!