SharpCap Sensor Analysis - How to!
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- เผยแพร่เมื่อ 10 ก.พ. 2020
- Update May 21!
I am slowly in the process of demonetizing all my videos, I was never in it for the money or the glory. I just like to help people. This way you can rest assured i'm not making a video only to trigger an algorithm or as click bait. I have been a bit disillusioned with it all lately, and hopefully this will help.
Instead if you wish to support me you can buy me a coffee or beer instead :) entirely your choice though!
www.buymeacoffee.com/astrostace
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This video shows you what i consider the first essential step when you get a new astro camera - carrying out a sharpcap sensor analysis!
Doing a sensor analysis gives you useful information about your camera sensor such as:
-unity gain
-noise levels
-full well depth
It also also allows you to use the very useful smart histogram tool in SharpCap Pro
the smart histogram tool at the end of the video should be run when your equipment is set up and pointing at a relatively dark piece of sky .
the camera in the video is the new Altair astro hypercam 269c pro Tec (full review coming soon).
order the Altair hypercam 269C Pro Tec here 👇
www.altairastro.com/altair-hy...
Disclosure: Bear in mind that the link in this post is an affiliate link and if you go through it to make a purchase I will earn a few pennies (at no cost to you) which in turn helps to support my astro gadget habit and keep all the reviews coming :D - วิทยาศาสตร์และเทคโนโลยี
Amazing. All these years I've been running experiments to determine read noise, e/ADU, etc. How marvelous to have this automated. Thank you!
Many thanks for this, AstroStace. I'm an old duffer but really appreciate your clarity and style. I've has ZWO ASI 1600MMC and 290MMC for nearly 4 and 2 years, respectively. I've always dodged sensor analysis, although I use Sharpcap Pro for most of that time for image acquisition and PA. You've converted this old fool into finally getting his act together. Thanks again.
Regards
Roger Snee
Love this sensor analysis! I heard this first from Mitch! You did explain it well! Definitely need to add to my workflow! Awesome video Stace!
Thanks Ray! Yes it's a useful tool!
I heard about this feature in Sharp Cap pro while working in NINA. I had Sharpcap a few years back but this is really interesting. You did a great job in the demo and explanations. Thanks
I was unaware of the availability of that function. Thank you for bringing it to my attention.
Thanks Stacey. Great resource. Professional job.
Fascinating, sensor analysis in Sharpcap. I have not used it because i use ASIAIR in the field. I will perform this experiment at home, thanks for the tutorial. Great help as usual.
Hi Stace just acquired a zwo asi 533 pro so this is very useful to me. Having a go tonight- so I’ll let you know how I got on. Great and clear explanation as always. 👍
Outstanding! I’ve often wondered what that was all about. I’m going to do all my cameras now because that brain thingy looks super useful! Thanks Stace!
Great video thanks! I've just watched a video by Robin Glover, the creator of SharpCap, on the optimum gain for CMOS imaging. In it, he says that unity gain is not the optimum gain setting. Rather for cameras with 2 stage gain processing, he suggests the optimum is the point just after the "read noise cliff" on the read noise vs. gain chart. For my ZWO ASI294MC Pro camera, that equates to a gain of 120. I'm going to run the sensor analysis in your excellent video and see what unity gain comes out but I suspect that will be much higher. Thanks again for posting these videos.
Cheers Stacey, nice project for the cloudy evenings !
Definitely! Let me know how you get on!
Thanks. I’ve never seen a TH-camr mentioning this feature before!
Nice video!Thank's for this!
Hi Stace, just watched this again (I now have an astro camera - Altair 327C woo!) and - having watched this vid - I've now been able to perform a decent sensor analysis. Still haven't used the camera yet...time, weather etc but now feel more confident. Thanks.
Cool video, Stace! I didn't knew you can to the sensor analysis like that. Actually, I have never done it before. I have to check if I can do this with SharpCap 3.1, because I don't have the Pro version. Thank you for another helpful video, Stacey! :-)
Got in from work at midnight thinking if there are apps for quick camera settings. Just incase my camera makes it out the box this year. Up pops Stacey with an explanation on the subject, saving me searching.
You must be psychic Stacey. Thanks for your help, nice video.
Haha glad I can help Melvin! 😁
Hi Stacy, good video. I used this with my Altair Astro Hypercam183C and the results were very useful.
Ah great! Glad it helped!
very helpful video, thanks!!
Great video! 😊 Thank you
Great video. I did this process with the camera plugged into a USB2 port (not paying attention), which took a very long time. Then I switched to a USB3 port and it went very quickly. Obvious really, but might explain why some people have complained about it taking hours to complete.
Thank you for the video very useful thanks again
It makes more sense now. Thank you! I tried to run it but they don't say how bright of light to use. So I pointed it at a white lamp shade. It told me it was too bright. So I pointed it at the ceiling and it was not bright enough. So I gave up on it. I hadn't thought about using a tablet, but still wouldn't have known how bright to go with it.
Yeah a lot of folks struggle, so you aren't on your own :) I tend to go 3/4 of the way towards minimum brightness. But it's much easier to tweak the brightness of a tablet to suit :)
Very nice! New that I will try
Wow, have not seen green and yellow worms for a long time. Great vid.
Thanks for the video, what else to do on a very wet day. Sensor Analysis of course on my new AA 269C. My results were very similar to yours with a Gain of 567 and eADU of 23220. I did have 2 problems running the analysis in that I could not select an area. All I could see was a single red arrow. Putting the view to 100% from auto showed up the box, so I could expand it, sorted. Next was the light level of my Tablet, even on its lowest setting it was still to bright, so I used some Neutral Density film to bring it down. (Also worked with a Polarising Filter), sorted, the light level has to be really low!! May help others. Thanks again.
Well, I believe this is the approach that will give a better approach. So, I analyzed this batch of camera yesterday
So my Zwo list.
1600mm Pro , 2 - 183MC Pro, 2 290MM, 290MC, 2 -178MC, 2 - 120MM-S, 120MM.
What I find interesting is that each manufacturer handles gain ( the values we use ) differently . For example your optimal gain value is in the 500s. My cameras are all in the 100s. I’ll be getting a Altair guiding camera, it’ll be fun to check that out.
Cheers
I just tried this with my 2600mc noticed it needed a T-shirt over a very dim Tablet to work kept over exposing and the process would stop. Great video very useful.
thx stace very interesting and not something I've ever done. Gonna look at if for my old canon 5d mark ii
Ahhh sadly doesn’t work with dslr. Astro camera only! :(
I performed this analysis for the first time on my ASI183MC Pro. According to the ZWO website, unity gain is 120, but my analysis gave me 115. I may have been looking at the ZWO chart wrong but I'm not sure. Thank you for the education Stace.
Great video Stace. Just watched Dr. Glover's presentation about calculating exposures where he shows that shorter may be better. I've had SharpCap for a while but never really used the analysis tool. However I'm now more inclined to give it a go. Really appreciate the technique of using your tablet, never would have though of that. :-)
Yeah it's much easier to adjust the brightness of a tablet :) leads to less frustration hahaha
Thanks Stace! This is a great video and I had no idea SharpCap had this capability. I wonder, can it be done with a DSLR as well? When I get back up and running, I'll do this.
Can I safely assume that each night attached to the telescope you should run the last part of this to get the best exposure for that night's seeing and light pollution?
I really think this is great, and it's why I like your channel so much, detailed information in easy to digest pieces.
Thanks for the great feedback Gary! Yes you could run the smart histogram tool each night to take into account the differing sky conditions...also if you change part of your setup eg a filter. It's a useful tool. I don't believe it works with DSLR though sadly :(
Nice one Stace... well useful....
Cheers Mark! :)
Thanks again Stace. I have moved from a DSLR to a new ASI533MC and haven’t done flats yet as it’s so confusing working out the correct ADU etc. and everyone’s way of doing things. So looking forward to your next vid. In the mean time I’ll try this check and get up to speed. Cheers John.
No worries John! Yeah I shall get on that video...there's just a couple more things I want to research first :)
I'd be interested in hearing about your experiences. I've had some struggles connecting the ASI533MC to Sharpcap. Ended up using an ASCOM connection.
Larry Doucet I haven’t tried connecting yet as I use a ZWO ASIAIR for capture. Will try on the weekend.
Ahh that’s what I did wrong, I still had the camera connected in the telescope the entire time, will have to take it out and try again using the light panel, had it pointed at a bright wall but I’ll try it out see if there is much of a difference, going to a Astro cam from a dslr lots of new things to learn but well worth it
Hi Stace - thank you for the video. Ive been trying for hours to get this process sorted and my camera just wont have it. I have the latest version of SharpCap and an Altair 294c. I always seem to get to the third and last stage when I get an error that I need to reduce the brightness. Ive gone around that process about 6 or 7 times now. The only thing I noticed different about your video is you have the analogue gain turned full up when you start. To start with I had mine at minimum, so I upped it to 500 but it didnt make much difference. Is that important? Struggling to go any darker on the light source as I cant get the frame below 2s otherwise. Aarrrgghh!!!
Thanks for this Stace. I've always just assumed that longer exposures, even at unity, equalled better images. Didn't realise that there was an optimal exposure length as well 🙈
Yes! It's definitely worth looking into :) for example let's say the optimum exposure time is 120s but you're just doing 180...that's a whole 60s wasted!
@@AstroStace mental note to do this, hopefully tomorrow evening 😊😊
Great video, will do this soon. One question though. When you say ideally you would have your camera attached to your telescope (7:14) , is that at night time outside with the lens cap off or indoors with the lens cap on? Thanks.
Hello Stace, First, I just want to say I just found your channel and after watching this one video, I've subscribed so I'll be notified when you post more. My next treat is to go back and watch all your other videos.
I do have a few questions regarding this Sensor Analysis that you didn't mention in the video. The answers may be obvious but not for a newb like me.
1. When running the first part of the analysis, do you need to have the sensor cooler on and cooled down to your normal shooting temps?
2. On the second part of the process where you need to have the camera on the scope behind the filters, Do you need to be in a truly dark sky location or could this be done while set up in a light-polluted backyard? Would the results vary between the backyard and a true dark sky site?
3. Also, for the second part, Do you need to run this analysis through every filter or just the Lum? I've got an 8 position wheel with LRGB,Ha,OIII,SII filters
4. At 08:55 I see the graph mentions "optimal black level". I don't see any way of adjusting that on my camera?
Looking forward to your answers and your other videos.
Here's the results from running the first part on my ZWO1600mm. The manufacturer states unity gain is 139 which places it right about where this graph puts it. photos.smugmug.com/photos/i-GT422HJ/1/dbeabae8/X2/i-GT422HJ-X2.png
Hi Grace, Didn't you make the field video for sensor analysis? it would be interesting to see it ... maybe it's me who can't find it ...
I’m going to try a sensor analysis on ASI294MC Pro. So far I’ve been getting satisfactory results making manual adjustments on sharpcap settings. Two targets eludes me M31 and Barnard 33. I could not ever for the love of God can’t pull full details on these two. I’ve checked Astrobin, Hyperstar groups and they where able to get a complete image for just an alt-az mount and 30” subs. I know how to a simple stretch but these two can’t be stretch to get more details. Running an Celestron Evo 8” ASI294MC P + Hyperstar and L-Pro filters with max sub exposure times of 30”.
Nice one , but how do you change the colour on sharpcap my grey sliders are difficult to read in the dark.
Hi Stace
Can you run this camera analysis on a CCD camera.
Cheers Paul and Chrissy.
Great video; so after the sensor analysis and when you connect the camera to your scope, does the scope need to be focused on a night sky object? Also, how do you set the dark level, thru the histogram?
On a dark area of sky, not your target :) use the brain smart histogram and it should be able to help you set the offset
Thanks for the presentation. Quick question though: at what temperature the camera should be when doing this analysis? Is temperature not a factor when doing sensor analysis? Thanks a lot.
I found it didn’t make much difference to me whether I cooled the camera or not :) but to be absolutely thorough, you could run it at the the temperature you intend to capture your images at
Many thanks Stacey. Really helpful video.
How does Sharpcap save the sensor analysis data for next time? Cannot see a 'save' option. I guess the Histogram Brain function needs to access that sensor analysis data when I start up my laptop & SharpCap somehow. Or do you have to run the sensor analysis every night?
No worries Francis! It actually saves it automatically somewhere, so don’t worry as long as you have run it, it will be able to access the information it needs
@@AstroStace That's great. Thanks! You are so knowledgeable Stacey. Have run it now for both RAW8 & RAW12 on my protec. The brain function picks up the data for each - amazing!
I like the approach, however, I can't get this to work for my Altair Astro Hypercam 1600M Pro TEC
Excellent information. I had a problem though; after completing the analysis successfully, NINA pulled in the wrong data from the SharpCap file. For instance, my full well was around 19k and Nina pulled in a number of around 4k...any idea why?
Good info Stace! Planning to do the analysis on two of my cameras for the first time. Question: how did you set up your iPad screen to provide the bright flats screen? I have a Samsung Galaxy tab that I'd like to use for that purpose. Thanks! Craig
Hey Craig I got it on a blank screen and pretty much put the brightness quite low! Took a bit of trial and error! Good luck!
@@AstroStace Thanks Stace and happy holidays! Craig
Hello Stacy I have tried to do a sensor analysis but the light I have to use is almost a very dark grey before it proceeds. So how are you able to do an analysis with such a bright light? I really find it hard to understand my equipment which seems to be out of step with every setup I see. My camera is a ZWO 294MC Pro camera.
Quick question on the histogram tool. The total stacking time would you change that to say 180 mins if you were planning a 3hr session?
Yes that’s right :)
tablet "flat panel", brilliant.
Can you do the sensor analysis with cameras still attached to OTAs - pointing to a illuminated white frame whose intensity is dialled right down?
Never heard of this before. How would this be expected to work on a modified DSLR, such as full spectrum or red filters removed? Also, would a CLS-CCD be an advantage of increasing SNR?
Another great tutorial. I'm so impressed.
After watching this very informative video I found myself having even more questions. Hope someone will be kind enough to bring some knowledge I could use in practice. Here are my questions.
1. I have successfully completed sensor analysis. Now I know what is best gain value for my camera however I run this at home. We all know that there's is no two exactly the same nights. My question is this. Would you recommend running sensor analysis every time I'm imaging? Logically by doing this I can have best and most accurate data so sharpcap can determine best gain, exposure time etc?
2. As I live in heavy light polluted area I'm likely to use light pollution filter. Having said that, do I need sensor analysis done with or without light pollution filter?
Glad you liked the video :) nope you only have to run the sensor analysis once :). But what you can do before each session is to run the smart histogram tool, this will suggest some optimum exposure factors :) . You don’t have to take it’s recommendations but I find them a good starting point.
As for the filter, if you plan on using a filter during a session, just run the smart histogram tool with the filter in place...it will then suggest optimum exposure factors with that filter in place :)
@@AstroStace you are the star 😜 Thanks !!!
if I point at different targets, I will get different exposure recommendations correct?
Hi Stacy,
Just a quick enquiry. If i am doing Narrowband imaging with a mono camera, would you run the sensor analysis function with a Narrowband filter in place ?
Cheers John
So sensor analysis without the filter in place....but if you wanted to make use of the smart histogram tool you would then run the smart histogram tool with the filter in place :)
So basically sharpcap would know the characteristics of your sensor without the filter interfering, and then could calculate the optimum settings with imaging with the filter by running the smart histogram tool with your filter in the imaging train
@@AstroStace Thanks for the heads up Stacy :)
Thanks for this. I'm just starting with an astro camera and my exposure settings have been a bit random so this is really useful. Can you explain why it's a good thing to aim for unity gain? I'm another one looking forward to the video on determining the ADU for flats, so you've got your work cut out for you!
I prefer to aim for unity gain as at this setting 1 electron = 1adu and theoretically you get less quantisation error...in short I just see it as a 'sweet spot'. I've found with aiming for the max dynamic range setting images are noisier and you would need a lot more subs to even out that noise ....so for me and my situation I find unity gain is better :) hope this helps!
It also depends on your setup too. So aiming for max dynamic range may mean a lower gain....and thus you may need longer exposures to overcome the read noise in the camera. So really people should assess their kit and decide from there. But for a beginner I think aiming for unity gain is a good step :)
@@AstroStace Ta, I get the gist of that. It looks as though you didn't have the camera cooler powered. So I assume that the sensor analysis doesn't vary very much with termperature?
@@AndyMcGregor2 it shouldn't do, no...as I'm literally just looking at the sensor characteristics. Though just for completeness I have previously run the sensor analysis cooled and uncooled and got the same results :)
Hi Stacey. I'm hoping for a delivery tomorrow of a 269c so some analysis coming up here. what setting did you have your tablet on please. Congratulations on the FRS, well deserved.
Hi Steve! Congrats on your purchase! I would make sure you set your tablet brightness low enough that a 1ms image isn’t classed as too bright when you’re doing the analysis:) so quite dim really !
Also thank you very much! :)
Should this be done with cooling?
Just how much do you spend on equipment ?
Would be most interested in seeing how this analysis leads to an optimum flats ADU :).
A monochrome camera could be checked in the same fashion, I assume?
Indeed! Mono cam exactly the same way :) I'll be doing that video on calculating the flats adu soon ...I've ordered myself a whiteboard for the video haha
That camera looks like it is cooled. Would the data be different if you did the tests with the camera cooled?
Is there any option for sensor cleaning?
It's strange, but in SharpCap 4.0 I don't have a Brain tab in the histogram. Maybe it's activated somewhere?
Hi
Iam a newbie.
Sharp cap says it does live stacking? What is this,is there no need to use other stacking software?
Hi, What about offset relative to the gain it recommends?
I usually just go with the offset that the smart histogram tool (at the end of the video) recommends :)
can you help me, I tried this analysis , but it keeps telling me Exposure too short, reduce lighting to increase exposure to at least 0.5s. I tried sliding the exposure control but it keeps bouncing back to 450ms. Thanks
hi stace i have a question , how are you powering the 269c without power i have tried mine and nothing unless i plug in the power lead , even used an active 3.0 cable
Mine works fine through the supplied USB 3 lead. Obviously the Tec doesn’t work without power but I can still use it with just the usb3
Thanks stace ill look in to that , wasnt sure if u had edited the video for some reason
Cap on or not? for histogram Ty
Great video, small tip, less on the sped up video, maybe cut away then come back when done, also you need to give us a chance to read the tips towards the end you cut away too early as there is a lot to take in. Otherwise a lot of ideas and tips thank you.
Thanks Nick! This is super helpful feedback. Will make sure I don't cut away so soon next time :)
Thank you for the video but unfortunately you confused at the end. Did you actually point the telescope towards the sky or not? If yes, what was your f ratio and how dark is your sky? That info was missing and is quite important.
It’s not important, to use the smart histogram you just have to point it at a dark patch of sky. I was merely just using it as an example. Sharpcap smart histogram sorts the rest. 👍🏻
So is this method you show here a means to do this so we don't have to do this in the cold? Also, do you have your sensor on when you run this sensor analysys?
You can run the sensor analysis from inside yes, but the smart histogram tool (the bit at the end) should be run when your camera is connected up to your scope etc. Sensor on? I'm not sure what you mean
AstroStace, thank you....I apologize I meant the cooler, not sensor...silly me.
@@gwzapo you can if you wish :) I've run it with cooler on and cooler off and not found a lot of difference. That's because read noise is different to thermal noise :)
AstroStace thank you so very much for the quick responses!
@@gwzapo no problem! Best thing to do is run it with the cooler and without to see if your results vary a lot
Good stuff..! I'm checking mine now...ASI294MC Pro
Great video! I will buy my first astro cam soon. Do you measure your ADU each night you are imaging?
Hi! No I just do the sensor analysis once and then I work out my target adu for my flats when I have the info on the full well depth (I'll cover this in another video). On an imaging night I tend to run the smart histogram tool in sharpcap to work out the best camera settings for my set up that evening...I always shoot at unity gain though :)
@@AstroStace Okey thanks! Can you make a video on all steps that you do on a imaging night? How you choose target, mount setup camera settings, framing etc. All those things that you do in a night.
It will be a long video but it will make people understand those small things that some people forget to explain :)
Yes absolutely, this is definitely the kind of video that is missing from my channel...but I shall get on it asap
What’s the point of unity gain? I don’t see why people prefer unity gain if it has lower dynamic range
don't do that ! great video but never put your laptop on a carpet like that ! the heat is trapped inside and the battery may explode ... and we only have one AstroStace .