Hello, if I'm using a filter do I still use the same ADU ? I've just got myself an ASI294 MC pro with an opt lextreme filter. Also thanks for the video 👍👍
@@vix2740 hi mate yeah you'll still be aiming for similar ADU units. What you'll find is your flat exposures are longer also to reach the correct illumination
@@AstroFarsography how would you determine the correct exposure and illumination for your flats ? This is my first time using an OSC and I'm finding it a little difficult to understand. Thanks 👍😁
Thank you Ruzeen! I watched so many videos on Flats and Flat-Darks, and none made so much sense as this one! I will try this now for my new 2600! Thanks again!
I've never used the Flats aid in APT before, just made 1 second exposures and adjusted the brightness of the tablet. But since you can save these plans for different filters, i'm gonna create those in the future. Thanks Ruz!
Such a Help !! I use a ZWO camera and APT.. No where else has anyone explained it like you did. Now I can make a set of flats for each filter. Thanks so much.
Flat frames typically are the most important calibration frames. Darks and bias on a dslr are a lot less noticeable in the final result. The only thing I question is using av mode. That usually puts the Hpeak in center. From what I have learned is that you really want the peak to be about 1/3 from the left. I started doing that and it seems to work out better.
Yes I've heard about the 33% rule as well, as well as 30-50£% and 20-40%. Can't say I tested it myself honestly but the 50% never has steered me wrong. You could still use AV mode but add -1 stop exposure compensation in. I have noticed that my master flat runs in at 33% luminosity anyway so maybe there is something to taking 33% flats!
Hey mate, that was a great tutorial! I used to do the T-shirt method with DLSR's but I was a sucker for punishment and tried to do them the same night using a torch shone 'evenly' over the aperture. It did work but was more awkward than doing it in the day I should imagine. I had no clue about flats for dedicated astro cameras with the ADU units, so a big thank you for that! I'm sure that will come in very handy. Flats are worth the effort for sure, it's nice to be able to stretch the image without gradient and dust bunnies immediately popping up! lol
Nice explanation Ruz! I use a similar tool in Ekos, I have a 16 bit camera (AtikOne 6.0), I set my target ADU to be 22000, this gives me the histogram curve at around a 1/3rd of the way from the left, the maths I used was similar (2^16)/3 which gives 21845.3, I round this up to 22000. I have read that the target histogram peak should be between 25% and 40% of the histogram so 22000 falls right in this zone.
Thanks mate. Ive seen EKOS kicking about and always meant to check it out. Yeah, one other mindset I've seen about flats is 33-50%, others say 20-40%. I personally use the 50% method and I can't say I've been caught out. My flats come in at 50% but my master flat is 33% so I kind of feel DSS sorts the luminosity out anyway. Clear skies!
Thanks Dennis! Yeah getting caught up and finessing the exposure is easily done. But unnecessary as they get averaged anyway? The flat aid is a right helpful bit of kit, glad you'll be getting in on that
ADC = Analogue to Digital Converter ... so the signal (readout as a voltage) collected in each of the pixels is digitised typically with 12, 14 or even 16 bits digitisation. That is with a max of 4096, 8092 or 16384 possible numerical values (channels in the histogramme) in each case respectively.
Thanks Matt. What's the new cam? It is kinda straight forward once you've done it a couple times. You can get an LED light panel as well to make life even easier.
I think most astrophotography programs stretch the image to 16 bit, I know this is the case with SGPro and NINA, and I suspect it is true with APT. In fact, when you were running the flat tool, the first exposure came out with an ADU of 65528 so it is 16 bit. I know this confused me for a while, but it makes the whole issue of setting your target ADU much simpler since, irrespective of your camera bit depth, your target ADU should simply be in the region of 30,000. By setting your target at 8000 (14 bit) or 2000 (12 bit), you would be running at about 12% or 3% of the full camera range respectively. 12% should be OK as cameras sensors should be linear over that range, but using 2000 with a 12 bit sensor when the image has been stretched to 16 bit is very low and I suspect the flats would not work so well bearing in mind the offset could easily take up a fair proportion of that 2000 ADU signal.
This is 100% correct. I have a 14-bit camera but the ASIAir Pro stretches the ADU value to a 16-bit value, so I always aim for an ADU in the region of 30,000.
@@stormingbarney4498 Yeah, I have an ATIK 383L (16 bit), ASI294MC-Pro (14 bit) and an ASI183MC-Pro (12 bit), and I aim for a mean ADU of 25000-ish whether its in NINA or SGPro for all of them. My main problems are that the 383L needs a minimum exposure of 5 seconds (I've seen even higher figures quoted) because of the mechanical shutter, and the ASI294 has to go at 3 seconds otherwise I seem to get some really odd results if I shoot the flats quicker. I ended up modifying a flat panel from Amazon (other suppliers exist 😁) using an arduino to control the brightness all the way down to almost invisible. But if I shot for 2000 with my ASI183, I really am not sure what would happen as the DarkFlat ADU reading would probably be around 800 of that 2000 so my flats would be at around 2% of full-well depth - I don't even know if the sensor is linear to such low values? I appreciate that this is only really a problem for 12 bit cameras, but doing flats is enough of a problem without shooting for an unrealistic value.
Thanks for the comment and it makes total sense what you say about the fact its a 16 bit application but I entered in 14bit values. I actually went and checked my raw flat frames via the 14-bit method and they read ~50% luminosity on the histogram. So it seems to still work fine even though it's stretched to 16. My master flat is 33% luminous though.
@@AstroFarsography I maybe haven't expressed things very well. My understanding is that because APT (and SGpro, etc) scale ADU readings to 16 bit, the target ADU should always be 25000 to 30000 irrespective of bit depth of the camera’s ADC. I do this with my ASI183 which is 12 bit, and with 30000 ADU on my flats, Pixinsight shows that they are about 50% saturated. If I set the target at 2000, I end up with very dark flats with probably highish noise levels. As I say, I believe your figures will be OK (but maybe not ideal) for 14 bit cameras, but are not OK for 12 bit cameras.
The confusion arises because of this scaling! The numbers you gave were correct for True ADU values, but I thought it was only SharpCap that actually reported those values on its histogram - I don't have APT so I really don't know about it. Certainly NINA and SGPro work on scaled values only.
I use a light box (also called LED drawing board, tracing board on ebay) powered by a power bank. I place a plain sheet of paper over it, taped at the back. I can then take the flats immediately after the imaging session.
Great! I'll be using this (one day) when I get a dedicated camera ! Flat frames with a DSLR - don't forget to cover the viewfinder - on my Canons I get light bleed if I forget!
Great video. I don't use APT. I use ASI studio and have and asi533. How would I use my target ADP number in a program that doesn't calculate the result automatically?
Well from what I've learnt so far on the comments here, you need to see whether ASI studio uses the cameras bit depth or stretches it. Take a bright image and see whether the value peaks at 16000 or 65500. If it peaks at 65500 then target 25-30k Nd if it's 16000 then target 8000 or so
Cheers Ruz, that was very clear and concise, interestingly I have a really good AP guy on my forum. Always lights only, this is on a 102mm triple APO, ASI 533 OSC, or 1600MM. Does this setup eliminate the need for flats & darks in some way? I won’t try this, I need all the help I can get, moving to DSO from planetary is quite a transition.
Thanks again for a great video. Do you produce flat frames for every session or should we have a set of Master flats. Considering that the focus won’t change for DSOs ..?
I do flats for every session. Sometimes I find the focus is slightly out between sessions (temperature and materials changing size and shape). So I make flats each session. I do have the luxury of just putting the scope inside before needing to tear it down so I can shoot the next day
Hi! I Have a question about buying a telescope for astrophotography So i have a Canon 450d (APS-C) and a used Heq5 goto mount which i spent most of my money on and it's pretty much on my budget limit so i was wondering, should i buy a newton like 150/750mm f5 or 130/650mm f5 or maybe i should try to buy a refractor? I know that refractors are much lighter and easier to use and maintain and usually have really nice image quality, but for me newtons are way more affordable although i know that it needs more cleaning, and frequent colimation and they're heavier but i think it will not be a huge deal for me because I've been using one (dobsonian 8"), but I'm wondering if the quality of images from newtons are good?, do you have any suggestions on which one should i choose for my first astrophotography telescope?
Ruzeen how would you make dark flats with an LED panel? It seems like you need some light and not pitch dark conditions....if I was to make my flats and dark flats at night....
if I point up to the sky what is the usual exposure time? I tried it manually before and the results were terrible because I had no idea what I was looking for.
Thanks Ruz. Very informative. When you take dark frames, do you use exactly the same steps you showed but with telescope cap on? I thought darks should be the same exposure as your light frames
Thanks mate. So there's two kinda of darks. There's dark frames for your lights. Then there's dark flats. Darks are the same exposure as your lights Dark flats are the same exposure as your "light" flat frames if that makes sense
Hello Ruzeen and a Merry Christmas ! With regards to taking FLATS with a DSLR , is there any suggestion or importance on which Metering Mode should be used ? I have Evaluative , Center-weighted , Spot and Partial as Options on my Canon Menu . Can't find anything online that tackles this Topic . Hopefully either you or your Subscribers might have some insight to this . Cheers ! /SRK
Hey buddy. I don't think metering mode will matter too much, since it's meant to have a flatly illuminated scene, metering would be (theoretically) the same through the entire frame (barring vignetting)
@@AstroFarsography Vignetting is exactly the reason for the question . The edges will have a different brightness when compared with the centre . We'll have to come up with a way to Test this . LOL . Cheers ! /SRK
Ah what I mean is the lens is a 1.8 lens but shooting wide open isn't a good idea, so I stopped it down to 3.5 when I shot my lights. Therefore I had to make sure the flats match the lights
@@AstroFarsography The ISO should be the same and in Av mode the histogram at 50%..In manual mode the focus wouldn't change when you turn the camera off. Tape is a good idea regardless
Hello Ruzeen, I noticed that the flats of your DSLR and your dedicated astro-camera had different colors; I took flats recently with my DSLR attached to the scope and the white T-shirt over the top, pointed at a blue sky away from the sun, but when I saw that they looked blue-ish, I just trew them away. I was used to take them with a computer screen in front of the telescope, and there they were perfect white - which I always thought they had to be? Thanks for clarifying! geert
Hey geert. I don't believe the colour matters. If you look at your master flat I bet it's grey. They were different colours due to filters and modifications. The DSLR is modified with no filter so it's really red. The dedicated was shooting through the L-eXtreme so it was more blue. Again, it's nothing I've ever encountered being a problem so carry on firing away :)
Great video thanks, i got my first dedicated camera ZWO183MC Pro. Thanks so much for this video had no idea how to take flats for dedicated astronomy camera plus i'll take a look at Astro photography tool
I've got the same camera, and I aim for a mean ADU of 22-30k. My main problem is the spread of peaks for the R, G and B pixels, especially if I'm using a LP filter or a duo-band filter. You find that the red channel is quite low and green is high, so I take at least 50 frames to try to drive up the SNR for the red channel.
on an Asiair pro to set the flat frames on a 294mc pro which is a 14 bit sensor the recommended adu settings are at 25000 how does that compare to your calculations?
Do I need to shoot dark frames too, when I m using ASI 533MC PRO??? I mean there is no glow effect, and if you shoot at -15 C its clear enough from noise.
When I used the 533 at -15°c I still used darks as it's s standard workflow procedure. Also it being a cooled camera you can create a dark library anyway so it doesn't become too hard to use darks. But at that temp, with dithering, you shouldn't have to worry too much about noise. Darks can just be an extra layer
Nah I've never noticed temperature to affect flats. You can temp match if desire but it's unnecessary. I'd match the temp for flats and dark flats though for the same reason darks match lights
@@dankahraman354 you're welcome. Just think of them as the dark frames for your flats the same way you do dark frames for the lights. They help calibrate the flat frames so need to be dark, and the same exposure length. That's it ☺️ good luck
If you can get to a totally empty part of the sky (clear skies or even clouds) then you won't need the shirt. The shirt just helps diffuse the light. You could try and get an LED panel as well to illuminate your scope but depends on your aperture
@@AstroFarsography Yes even lighting and away from the sun (opposite). I use panels when I make flats at night. Translucent plexiglass for large scope with scope pointing straight up in this case...the LED panel can rest on top-flush...
Its funny that the Astrodedicated Astrocams users telling us DSLR users, that we need to shoot exposure around 1 second. We mostly shoot on ISO800/1600. We always end up with way below 1 second. Mostly 1/60 till 1/1000. How to deal with this? Or ignore what they tell us?
Imo the t-shirt method puts more dust on your front objective than it's worth. I just purchased a 15 dollar led art pane to try . Hopefully it works. clear skies.
Well in lieu of the actual review, I can tell you that you won't regret your purchase. I'm just running through my backlog of videos at the moment that's why the CEM review isn't out yet 😣
@@andrewlindenfeld6222 I love how heavy and sturdy is, i did cable management, but not consistent with phd2 guiding. It could be seeing. I hope numbers improve.
@@enriquebechet1 www.cloudynights.com/topic/715180-cem70-has-arrived/ That’s a thread started on cloudy nights on the Cem70. It was a valuable resource for me so maybe it can help you out too! Just keep in mind that there could be the off chance of getting a lemon. That’s why it’s best to take the mount through its paces before you hit 30 days past delivery, in case there was a factory defect it’ll be much easier to get it sorted out if you catch it early. I had no problems with the mount but after the 3rd time using it my power cable went out. IOptron was very good about it though and promptly sent a replacement. How was the PE graph that came with the mount? I’ve seen a lot of people, myself included, who’s mounts are performing above the +/-3.5 arcsec. error PE spec. My guess would be the inconsistency was the seeing though. It’s been very poor around here, and if I had to describe the mount in a couple short words they would be “solid” and “consistent”. Best of luck and clear skies!!
@@andrewlindenfeld6222 thanks for your comment. My PE graph paper looks good just + - 3.5 arc sec. I just did cable management and went out last night. I was guiding from 0.8 to 1.4. Mostly. 1.15. Rms. I will test again late night (I am imaging bodes galaxy). Btw, I am using 8 in sct, focal length 2032 mm. But I was getting slightly better numbers with my heq5 pro w rowan belt.
Don't forget to check the timestamps and the description and jump to where you want
Hello, if I'm using a filter do I still use the same ADU ? I've just got myself an ASI294 MC pro with an opt lextreme filter. Also thanks for the video 👍👍
@@vix2740 hi mate yeah you'll still be aiming for similar ADU units. What you'll find is your flat exposures are longer also to reach the correct illumination
@@AstroFarsography how would you determine the correct exposure and illumination for your flats ? This is my first time using an OSC and I'm finding it a little difficult to understand. Thanks 👍😁
@@AstroFarsography sorry I just noticed the value inputs for the start and max exposures 😐
Thank you Ruzeen! I watched so many videos on Flats and Flat-Darks, and none made so much sense as this one! I will try this now for my new 2600! Thanks again!
Thanks very much Mohit I'm glad it was useful for you! 😁
I've never used the Flats aid in APT before, just made 1 second exposures and adjusted the brightness of the tablet. But since you can save these plans for different filters, i'm gonna create those in the future. Thanks Ruz!
Yeah they really are useful. It's a handy tool, fire and forget almost. Takes the guesswork out. You're welcome Tim!
Such a Help !!
I use a ZWO camera and APT.. No where else has anyone explained it like you did. Now I can make a set of flats for each filter. Thanks so much.
I had issues creating flat frames with my ASI2600MC and APT until....this video is excellent. Thank you so much. Worked first time 👍👍👍👏👏👏
Flat frames typically are the most important calibration frames. Darks and bias on a dslr are a lot less noticeable in the final result. The only thing I question is using av mode. That usually puts the Hpeak in center. From what I have learned is that you really want the peak to be about 1/3 from the left. I started doing that and it seems to work out better.
Yes I've heard about the 33% rule as well, as well as 30-50£% and 20-40%. Can't say I tested it myself honestly but the 50% never has steered me wrong. You could still use AV mode but add -1 stop exposure compensation in. I have noticed that my master flat runs in at 33% luminosity anyway so maybe there is something to taking 33% flats!
Amazing explanation, just getting started in astrophotography you helped me start to bring the numbers together. Thank you!
Hey mate, that was a great tutorial! I used to do the T-shirt method with DLSR's but I was a sucker for punishment and tried to do them the same night using a torch shone 'evenly' over the aperture. It did work but was more awkward than doing it in the day I should imagine. I had no clue about flats for dedicated astro cameras with the ADU units, so a big thank you for that! I'm sure that will come in very handy. Flats are worth the effort for sure, it's nice to be able to stretch the image without gradient and dust bunnies immediately popping up! lol
Nice explanation Ruz! I use a similar tool in Ekos, I have a 16 bit camera (AtikOne 6.0), I set my target ADU to be 22000, this gives me the histogram curve at around a 1/3rd of the way from the left, the maths I used was similar (2^16)/3 which gives 21845.3, I round this up to 22000. I have read that the target histogram peak should be between 25% and 40% of the histogram so 22000 falls right in this zone.
I was about to make this exact same comment.
Thanks mate. Ive seen EKOS kicking about and always meant to check it out. Yeah, one other mindset I've seen about flats is 33-50%, others say 20-40%. I personally use the 50% method and I can't say I've been caught out. My flats come in at 50% but my master flat is 33% so I kind of feel DSS sorts the luminosity out anyway. Clear skies!
This actually was a great video! I hunt and peck for the correct exposure a little but the flat aid will help a lot!
Thanks Dennis! Yeah getting caught up and finessing the exposure is easily done. But unnecessary as they get averaged anyway? The flat aid is a right helpful bit of kit, glad you'll be getting in on that
ADC = Analogue to Digital Converter ... so the signal (readout as a voltage) collected in each of the pixels is digitised typically with 12, 14 or even 16 bits digitisation. That is with a max of 4096, 8092 or 16384 possible numerical values (channels in the histogramme) in each case respectively.
Great video. Very helpful on taking flats using the APT Tool.
Spot on. Not done this yet with my new cam. Make it look quite straight forward. Thankyou.
Thanks Matt. What's the new cam? It is kinda straight forward once you've done it a couple times. You can get an LED light panel as well to make life even easier.
@@AstroFarsography Altair 269c. L Extreme filter arrived the other week too. Been nothing but rain and clouds though since about September. Annoying!!
I think most astrophotography programs stretch the image to 16 bit, I know this is the case with SGPro and NINA, and I suspect it is true with APT. In fact, when you were running the flat tool, the first exposure came out with an ADU of 65528 so it is 16 bit. I know this confused me for a while, but it makes the whole issue of setting your target ADU much simpler since, irrespective of your camera bit depth, your target ADU should simply be in the region of 30,000. By setting your target at 8000 (14 bit) or 2000 (12 bit), you would be running at about 12% or 3% of the full camera range respectively. 12% should be OK as cameras sensors should be linear over that range, but using 2000 with a 12 bit sensor when the image has been stretched to 16 bit is very low and I suspect the flats would not work so well bearing in mind the offset could easily take up a fair proportion of that 2000 ADU signal.
This is 100% correct. I have a 14-bit camera but the ASIAir Pro stretches the ADU value to a 16-bit value, so I always aim for an ADU in the region of 30,000.
@@stormingbarney4498 Yeah, I have an ATIK 383L (16 bit), ASI294MC-Pro (14 bit) and an ASI183MC-Pro (12 bit), and I aim for a mean ADU of 25000-ish whether its in NINA or SGPro for all of them. My main problems are that the 383L needs a minimum exposure of 5 seconds (I've seen even higher figures quoted) because of the mechanical shutter, and the ASI294 has to go at 3 seconds otherwise I seem to get some really odd results if I shoot the flats quicker. I ended up modifying a flat panel from Amazon (other suppliers exist 😁) using an arduino to control the brightness all the way down to almost invisible. But if I shot for 2000 with my ASI183, I really am not sure what would happen as the DarkFlat ADU reading would probably be around 800 of that 2000 so my flats would be at around 2% of full-well depth - I don't even know if the sensor is linear to such low values? I appreciate that this is only really a problem for 12 bit cameras, but doing flats is enough of a problem without shooting for an unrealistic value.
Thanks for the comment and it makes total sense what you say about the fact its a 16 bit application but I entered in 14bit values. I actually went and checked my raw flat frames via the 14-bit method and they read ~50% luminosity on the histogram. So it seems to still work fine even though it's stretched to 16. My master flat is 33% luminous though.
@@AstroFarsography I maybe haven't expressed things very well. My understanding is that because APT (and SGpro, etc) scale ADU readings to 16 bit, the target ADU should always be 25000 to 30000 irrespective of bit depth of the camera’s ADC. I do this with my ASI183 which is 12 bit, and with 30000 ADU on my flats, Pixinsight shows that they are about 50% saturated. If I set the target at 2000, I end up with very dark flats with probably highish noise levels. As I say, I believe your figures will be OK (but maybe not ideal) for 14 bit cameras, but are not OK for 12 bit cameras.
The confusion arises because of this scaling! The numbers you gave were correct for True ADU values, but I thought it was only SharpCap that actually reported those values on its histogram - I don't have APT so I really don't know about it. Certainly NINA and SGPro work on scaled values only.
This was very well explained and you taught me a valuable lesson in regards to SLR sensor retraction! Great stuff!
I use a light box (also called LED drawing board, tracing board on ebay) powered by a power bank. I place a plain sheet of paper over it, taped at the back. I can then take the flats immediately after the imaging session.
Very nice video, I did my flats wrong, now I know better, thanks a lot. CS!
Very useful your videos! Cheers from Spain!
Congratulation, GREAT JOB!
Great! I'll be using this (one day) when I get a dedicated camera !
Flat frames with a DSLR - don't forget to cover the viewfinder - on my Canons I get light bleed if I forget!
Great video. I don't use APT. I use ASI studio and have and asi533. How would I use my target ADP number in a program that doesn't calculate the result automatically?
Well from what I've learnt so far on the comments here, you need to see whether ASI studio uses the cameras bit depth or stretches it. Take a bright image and see whether the value peaks at 16000 or 65500. If it peaks at 65500 then target 25-30k Nd if it's 16000 then target 8000 or so
Really well explained Ruzz. I’ve never bothered with dark flats but i know APP always asked for them. Are they worth it?
Thank you for this, I never knew how to do it with astro camera, but it’s running as I type 👍🏼👍🏼😊😊
Spot on video. You can use the flat aid with a dslr as well
thanks for this Ruzeen, very helpful, in fact i am in the middle of doing all this though with a light screen on the ota
Great Tutorial Ruiz 👍..!! Clear Skies ✨🌌
Thanks buddy, clear skies to you too
Fantastic - well explained and great information. Thanks for this!
Cheers Ruz, that was very clear and concise, interestingly I have a really good AP guy on my forum. Always lights only, this is on a 102mm triple APO, ASI 533 OSC, or 1600MM. Does this setup eliminate the need for flats & darks in some way? I won’t try this, I need all the help I can get, moving to DSO from planetary is quite a transition.
Thanks again for a great video. Do you produce flat frames for every session or should we have a set of Master flats. Considering that the focus won’t change for DSOs ..?
I do flats for every session. Sometimes I find the focus is slightly out between sessions (temperature and materials changing size and shape). So I make flats each session. I do have the luxury of just putting the scope inside before needing to tear it down so I can shoot the next day
Hi!
I Have a question about buying a telescope for astrophotography
So i have a Canon 450d (APS-C) and a used Heq5 goto mount which i spent most of my money on and it's pretty much on my budget limit
so i was wondering, should i buy a newton like 150/750mm f5 or 130/650mm f5 or maybe i should try to buy a refractor?
I know that refractors are much lighter and easier to use and maintain and usually have really nice image quality, but for me newtons are way more affordable although i know that it needs more cleaning, and frequent colimation and they're heavier but i think it will not be a huge deal for me because I've been using one (dobsonian 8"), but I'm wondering if the quality of images from newtons are good?, do you have any suggestions on which one should i choose for my first astrophotography telescope?
This is awesome, I had no idea about the Ccd flats aid. Thank you!
Ruzeen how would you make dark flats with an LED panel? It seems like you need some light and not pitch dark conditions....if I was to make my flats and dark flats at night....
Note when using a Nikon (D5300) attached to a telescope you can’t use Aperture priority mode like you can with a canon so judge the histogram
if I point up to the sky what is the usual exposure time? I tried it manually before and the results were terrible because I had no idea what I was looking for.
Thanks Ruz. Very informative. When you take dark frames, do you use exactly the same steps you showed but with telescope cap on? I thought darks should be the same exposure as your light frames
Thanks mate. So there's two kinda of darks. There's dark frames for your lights. Then there's dark flats.
Darks are the same exposure as your lights
Dark flats are the same exposure as your "light" flat frames if that makes sense
@@AstroFarsography Got it. Thanks again. Keep up the excellent work!
Thanks for answering this . Just thought the same as H H . Cheers Ruz .👍
@@AstroFarsography But you need a stacker which recognize those Dark Flats. Most stackers are only Dark frames and Flat frames.
Cool dude! Easy to follow, thank you!
Hello Ruzeen and a Merry Christmas ! With regards to taking FLATS with a DSLR , is there any suggestion or importance on which Metering Mode should be used ? I have Evaluative , Center-weighted , Spot and Partial as Options on my Canon Menu . Can't find anything online that tackles this Topic . Hopefully either you or your Subscribers might have some insight to this . Cheers ! /SRK
Hey buddy. I don't think metering mode will matter too much, since it's meant to have a flatly illuminated scene, metering would be (theoretically) the same through the entire frame (barring vignetting)
Though if I had to pick one for my camera I'd leave it default (evaluative I think), or I'd pick that or centre weighted
@@AstroFarsography Vignetting is exactly the reason for the question . The edges will have a different brightness when compared with the centre . We'll have to come up with a way to Test this . LOL . Cheers ! /SRK
Please clarify what you mean at 3:40...."If your lights are at f/1.8 why are your flats at f/3.5?
Ah what I mean is the lens is a 1.8 lens but shooting wide open isn't a good idea, so I stopped it down to 3.5 when I shot my lights. Therefore I had to make sure the flats match the lights
@@AstroFarsography The ISO should be the same and in Av mode the histogram at 50%..In manual mode the focus wouldn't change when you turn the camera off. Tape is a good idea regardless
Hello Ruzeen,
I noticed that the flats of your DSLR and your dedicated astro-camera had different colors; I took flats recently with my DSLR attached to the scope and the white T-shirt over the top, pointed at a blue sky away from the sun, but when I saw that they looked blue-ish, I just trew them away. I was used to take them with a computer screen in front of the telescope, and there they were perfect white - which I always thought they had to be? Thanks for clarifying!
geert
Hey geert. I don't believe the colour matters. If you look at your master flat I bet it's grey.
They were different colours due to filters and modifications. The DSLR is modified with no filter so it's really red. The dedicated was shooting through the L-eXtreme so it was more blue. Again, it's nothing I've ever encountered being a problem so carry on firing away :)
What about raw. Flat frames need to be in raw format, right?
Great video thanks, i got my first dedicated camera ZWO183MC Pro. Thanks so much for this video had no idea how to take flats for dedicated astronomy camera plus i'll take a look at Astro photography tool
I've got the same camera, and I aim for a mean ADU of 22-30k. My main problem is the spread of peaks for the R, G and B pixels, especially if I'm using a LP filter or a duo-band filter. You find that the red channel is quite low and green is high, so I take at least 50 frames to try to drive up the SNR for the red channel.
So why are you taking 10 shots? Do you stack the images?
Use decorators/masking tape to hold focus, easier to remove and leaves no sticky residue behind
on an Asiair pro to set the flat frames on a 294mc pro which is a 14 bit sensor the recommended adu settings are at 25000 how does that compare to your calculations?
From the sounds of it, as I've been informed by others on this video, it's stretching to 16bit so shooting at 25000adu is going to be 40% luminance.
Do I need to shoot dark frames too, when I m using ASI 533MC PRO??? I mean there is no glow effect, and if you shoot at -15 C its clear enough from noise.
When I used the 533 at -15°c I still used darks as it's s standard workflow procedure. Also it being a cooled camera you can create a dark library anyway so it doesn't become too hard to use darks. But at that temp, with dithering, you shouldn't have to worry too much about noise. Darks can just be an extra layer
Cheers buddy, always struggled with that whole target adu thing. Nice and simple explanation for dullards like me 😁
Haha yeah the ADU isn't intuitive at all so I'm glad I was able to help bring some clarity to it for you 😁
If you’re shooting at say -15°lights do your flats or darkflats have to be shot at the same temp?
Nah I've never noticed temperature to affect flats. You can temp match if desire but it's unnecessary. I'd match the temp for flats and dark flats though for the same reason darks match lights
@@AstroFarsography cheers mate.
Great video, mate! I'll keep it!
well i been capturing my dslr flat frames wrong this whole time haha
thanks for the great video!
Hey if they've been working for you, don't change! How do you shoot them?
AstroFarsography i use a bright LED light on top of a white t shirt, but I never focus on getting the exposure metre or the histogram in the middle.
@@astrowales5581 I used to use an led panel as well til I dropped and broke it. Made life much easier
Ruz are you taking your dark flats in the day time?
Yep absolutely. They're the same as flats just with the lens cap on so you can do them during the day
@@AstroFarsography Total surprise to me. I will do them that way in the future. Thank you....now I know why my dark flats didn't work
@@dankahraman354 you're welcome. Just think of them as the dark frames for your flats the same way you do dark frames for the lights. They help calibrate the flat frames so need to be dark, and the same exposure length. That's it ☺️ good luck
Very hard to do t-shirt and rubber bands daylight flats with very large scopes.
If you can get to a totally empty part of the sky (clear skies or even clouds) then you won't need the shirt. The shirt just helps diffuse the light. You could try and get an LED panel as well to illuminate your scope but depends on your aperture
@@AstroFarsography Yes even lighting and away from the sun (opposite). I use panels when I make flats at night. Translucent plexiglass for large scope with scope pointing straight up in this case...the LED panel can rest on top-flush...
Brilliant video once again mate. :)
Its funny that the Astrodedicated Astrocams users telling us DSLR users, that we need to shoot exposure around 1 second. We mostly shoot on ISO800/1600. We always end up with way below 1 second. Mostly 1/60 till 1/1000. How to deal with this? Or ignore what they tell us?
Imo the t-shirt method puts more dust on your front objective than it's worth. I just purchased a 15 dollar led art pane to try . Hopefully it works. clear skies.
Why is the flat frame pink? Mine is blue like the sky
Modded camera letting more UV through and not using a custom white balance :)
thanks so much
Focuse is actually not that important to get good flats😉 the angle the light falls on the sensor don’t shift much when you change focus.
Thank you😄
Thank you :-).
Good to know i have been doing it wrong xD i thought the histogram should be 1/3th.
You're not doing it wrong. I've heard 1/3-1/2 is the target. I just normally aim for 50% so that's what I taught :)
I was waiting for your cem70 review, I got the itch too strong, I ended up buying it. Lol
Good choice! I got one a few months ago and so far it’s been worth every penny!
Well in lieu of the actual review, I can tell you that you won't regret your purchase. I'm just running through my backlog of videos at the moment that's why the CEM review isn't out yet 😣
@@andrewlindenfeld6222 I love how heavy and sturdy is, i did cable management, but not consistent with phd2 guiding. It could be seeing. I hope numbers improve.
@@enriquebechet1 www.cloudynights.com/topic/715180-cem70-has-arrived/
That’s a thread started on cloudy nights on the Cem70. It was a valuable resource for me so maybe it can help you out too! Just keep in mind that there could be the off chance of getting a lemon. That’s why it’s best to take the mount through its paces before you hit 30 days past delivery, in case there was a factory defect it’ll be much easier to get it sorted out if you catch it early. I had no problems with the mount but after the 3rd time using it my power cable went out. IOptron was very good about it though and promptly sent a replacement. How was the PE graph that came with the mount? I’ve seen a lot of people, myself included, who’s mounts are performing above the +/-3.5 arcsec. error PE spec. My guess would be the inconsistency was the seeing though. It’s been very poor around here, and if I had to describe the mount in a couple short words they would be “solid” and “consistent”. Best of luck and clear skies!!
@@andrewlindenfeld6222 thanks for your comment. My PE graph paper looks good just + - 3.5 arc sec.
I just did cable management and went out last night. I was guiding from 0.8 to 1.4. Mostly. 1.15. Rms.
I will test again late night (I am imaging bodes galaxy). Btw, I am using 8 in sct, focal length 2032 mm. But I was getting slightly better numbers with my heq5 pro w rowan belt.
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