First planetary AP (untracked)

[sorrimen]

Hi all

Thought I’d share my first attempts at planetary AP. Shows some of the capabilities of an untracked dob set up, though I’m only just getting to grips with processing. Also planning to get a 3x barlow to get closer to the ideal f/ratio. Images are with a bog standard 8” dob and an asi224, along with the BST 2x barlow. Sharpcap 15k frames or so per image, registax 25% or 50% (going to start writing this in final file name for comparisons). 

Would appreciate any tips with processing, specifically registax. Finding it frustrating knowing I’m probably not maximising my data! 

Thanks for looking all!

 

p.s. final image is an animation that only seems to work when you click on it!

Edited August 19, 2022 by sorrimen
Adding p.s.

[johnturley]

Excellent images, far better than I've been able to achieve so far with my equipment, and ZWO ASI 462 Camera.

Curious as to what you mean by 25% or 50% in Registax, is that the %age of best frames, I usually use 50%, maybe I should try a lower percentage.  

Also, how did you enlarge Saturn in the second image, I've been struggling trying to find out how to do that. 

John 

Edited August 19, 2022 by johnturley

[sorrimen]

1 hour ago, johnturley said:

Excellent images, far better than I've been able to achieve so far with my equipment, and ZWO ASI 462 Camera.

Curious as to what you mean by 25% or 50% in Registax, is that the %age of best frames, I usually use 50%, maybe I should try a lower percentage.  

Also, how did you enlarge Saturn in the second image, I've been struggling trying to find out how to do that. 

John 

Thanks, John. That was actually a slight error on my part as I use AS!3 for my stacking, but yes it’s % of best frames. The % of frames depends on the capture quality and seeing across the whole video; more frames means less noise, but if the frames are of worse quality you will start to lose detail. That said, with my detail not being of such a high degree anyway I’ve found little difference between 25 and 50%, apart from the significant decrease in noise from using more frames. I must add that the size and number of align points has a noticeable difference. I’m hesitant to share my AP number aim, as it will differ entirely dependant on image size and your level of detail but I found that too many or too few have a significant effect on noise and detail so this is worth playing around with.

Regarding image size, I’ve had a look around your profile to see your equipment etc. The ASI462 has an ideal f/ratio around 12-15 (probably more like <12 in UK seeing, to the best of my knowledge), whereas the 224 sits a bit higher at around f/15-19. With your espirit 150 and a 2x barlow, you’re already at f/14 with only 2100mm fl. Essentially you’re likely above your camera’s ideal sampling size, but still not producing a very large image (2100mm fl). For reference, my images are at 2400mm but at f/12 are comfortably below ideal f/ratio. Staying below or at the ideal is important, as you are not recording more pixels than your telescope can resolve and introducing blur. The more important thing for image size is the ROI, as some others have mentioned in other posts. I used 800x600, which has the benefit of a larger image and higher fps. I saw that you were worried about decreasing resolution and no one properly answered you in this regard. ROI does not decrease the number of pixels used, it simply shrinks the area that is recorded by your capture software. Recording at full resolution, you could shrink the area in PIPP and get the exact same level of detail with a larger image size and I suggest you give this a go if you still have the original RAW captures. I’m not sure this would work after stacking though, but I imagine it could. Try the crop tool in registax for example. I would follow your own suggestion to try the 14” instead of the Espirit 150. Colour correction and contrast are simply far less relevant than being able to resolve detail and get a good focal length (image size) when it comes to planetary. I think I saw you said it has 1800mm fl so sits at f/5ish. With a 2x barlow pushing you to 3600mm and f/10, that’s basically as perfect an image size and f/ratio for your camera as you can manage untracked. You may even find that you want to tone down the fl so you can shrink ROI and push your frame rate, but I’m really waffling on now…

 

I imagine those of you with more expertise might cringe at my use of terminology, but I think I’ve got the principles correct so that you can try things out, John. That said, keep an eye out for replies just in case there are things that I’ve made mistakes on.

[sorrimen]

Thought I’d add John, I actually want my saturn to be a little larger so plan to push my focal length to 2.5x or 3x. At that point, you’re really at the limit if you are imagining untracked because you just don’t get enough frames of the planet drifting through. With your 14”, it should be plenty big.

[Astro_Dad]

Excellent images, and encouraging as I'm hoping for a first light with my new planetary cam in the next few days (including untracked with Dob also).

Well done,

A

[johnturley]

23 hours ago, sorrimen said:

 

Regarding image size, I’ve had a look around your profile to see your equipment etc. The ASI462 has an ideal f/ratio around 12-15 (probably more like <12 in UK seeing, to the best of my knowledge), whereas the 224 sits a bit higher at around f/15-19. With your espirit 150 and a 2x barlow, you’re already at f/14 with only 2100mm fl. Essentially you’re likely above your camera’s ideal sampling size, but still not producing a very large image (2100mm fl). For reference, my images are at 2400mm but at f/12 are comfortably below ideal f/ratio. Staying below or at the ideal is important, as you are not recording more pixels than your telescope can resolve and introducing blur. The more important thing for image size is the ROI, as some others have mentioned in other posts. I used 800x600, which has the benefit of a larger image and higher fps. I saw that you were worried about decreasing resolution and no one properly answered you in this regard. ROI does not decrease the number of pixels used, it simply shrinks the area that is recorded by your capture software. Recording at full resolution, you could shrink the area in PIPP and get the exact same level of detail with a larger image size and I suggest you give this a go if you still have the original RAW captures. I’m not sure this would work after stacking though, but I imagine it could. Try the crop tool in registax for example. I would follow your own suggestion to try the 14” instead of the Espirit 150. Colour correction and contrast are simply far less relevant than being able to resolve detail and get a good focal length (image size) when it comes to planetary. I think I saw you said it has 1800mm fl so sits at f/5ish. With a 2x barlow pushing you to 3600mm and f/10, that’s basically as perfect an image size and f/ratio for your camera as you can manage untracked. You may even find that you want to tone down the fl so you can shrink ROI and push your frame rate, but I’m really waffling on now…

 

I

Thanks for sharing the above information.

Based on imaging through the Esprit 150 (but not through the 14in Newtonian), its looks like I may have purchased the wrong Planetary Camera, and that I would have got better results with the (cheaper) ZWO ASI 224, however with its smaller pixel size of 2.9 um, as opposed to 3.75 um for the ASI 224, 2.1 megapixels as opposed to 1.2 megapixels, and max frames per second of 136 fps at full resolution of 1936 x 1096, as opposed to 30 fps at 1280 x 960, I thought I was getting the better camera, for not much more money, but maybe not, although FLO did recommend the ASI 462

I tried some imaging last night through the 14in, and also reducing the ROI to 800 x 600, but I couldn't see much advantage with the latter apart from taking up a lot less memory on my laptop, and there was NO difference to the size or the quality of the saved images (although you do get a larger image while carrying out the initial capture, and in the processing programs), plus the saved images annoyingly showed a dark immediate background against a lighter dark greyish background. Using the crop tool in Registax didn't make any difference either. Also although the images through the 14in were a lot brighter, and as expected about 1.7 x larger due to a focal length of 1,780mm as opposed to 1,050 mm, I can't say that I got a great more detail through the 14in, although to be fair atmospheric conditions were not as good as when I last imaged through the Esprit (on 13.08.22), as a significant breeze sprung up after midnight last night. 

Several people have previously recommended that you should be aiming for a focal ratio of about 3x the pixel size of the camera which for the ASI 462 would be 2.9 x 3 = f9 (equivalent to a 1.5 x Barlow) , but for the Esprit 150 at least, this just results in tiny images. 

I gather some people regard the Celestron 14 as the ideal camera for planetary imaging, as with a focal length of nearly 4,000 mm, you get decent sized images of Jupiter and Saturn, without the need for further amplification with a Barlow (may however need a 2x for Mars). I would have though therefore to get reasonable sized images,  you would want to replicate the effective focal length of the C14, which would be nearly achieved with a 2x Barlow with my 14in Newtonian (3,600mm), but require a 3-4 x Barlow (about f25) with my Esprit 150. 

I don't know whether like me, you've found a distinct lack of information available about what settings to use in Sharpcap in particular, such as the max fps rate, the exposure and the gain settings, I usually work around an exposure of 5 ms, max 120 fps, and leave the Gain on auto, but maybe I've got it completely wrong, I'll just have to keep going by trial and error until I get it right.

Incidentally, with the scopes being mounted on a driven fork equatorial mount, I do have the luxury of the image not drifting across the field of view when imaging. 

John 

 

Edited August 20, 2022 by johnturley

[sorrimen]

1 hour ago, johnturley said:

Thanks for sharing the above information.

Based on imaging through the Esprit 150 (but not through the 14in Newtonian), its looks like I may have purchased the wrong Planetary Camera, and that I would have got better results with the (cheaper) ZWO ASI 224, however with its smaller pixel size of 2.9 um, as opposed to 3.75 um for the ASI 224, 2.1 megapixels as opposed to 1.2 megapixels, and max frames per second of 136 fps at full resolution of 1936 x 1096, as opposed to 30 fps at 1280 x 960, I thought I was getting the better camera, for not much more money, but maybe not, although FLO did recommend the ASI 462

I tried some imaging last night through the 14in, and also reducing the ROI to 800 x 600, but I couldn't see much advantage with the latter apart from taking up a lot less memory on my laptop, and there was NO difference to the size or the quality of the saved images (although you do get a larger image while carrying out the initial capture, and in the processing programs), plus the saved images annoyingly showed a dark immediate background against a lighter dark greyish background. Using the crop tool in Registax didn't make any difference either. Also although the images through the 14in were a lot brighter, and as expected about 1.7 x larger due to a focal length of 1,780mm as opposed to 1,050 mm, I can't say that I got a great more detail through the 14in, although to be fair atmospheric conditions were not as good as when I last imaged through the Esprit (on 13.08.22), as a significant breeze sprung up after midnight last night. 

Several people have previously recommended that you should be aiming for a focal ratio of about 3x the pixel size of the camera which for the ASI 462 would be 2.9 x 3 = f9 (equivalent to a 1.5 x Barlow) , but for the Esprit 150 at least, this just results in tiny images. 

I gather some people regard the Celestron 14 as the ideal camera for planetary imaging, as with a focal length of nearly 4,000 mm, you get decent sized images of Jupiter and Saturn, without the need for further amplification with a Barlow (may however need a 2x for Mars). I would have though therefore to get reasonable sized images,  you would want to replicate the effective focal length of the C14, which would be nearly achieved with a 2x Barlow with my 14in Newtonian (3,600mm), but require a 3-4 x Barlow (about f25) with my Esprit 150. 

I don't know whether like me, you've found a distinct lack of information available about what settings to use in Sharpcap in particular, such as the max fps rate, the exposure and the gain settings, I usually work around an exposure of 5 ms, max 120 fps, and leave the Gain on auto, but maybe I've got it completely wrong, I'll just have to keep going by trial and error until I get it right.

Incidentally, with the scopes being mounted on a driven fork equatorial mount, I do have the luxury of the image not drifting across the field of view when imaging. 

John 

 

Interesting outcomes. The reason the larger pixel size may be preferred in this case is that it allows your ideal focal ratio to be higher. I’m not sure if there’s a slight misunderstanding, but I’ll try and clarify further just in case. You want to be aiming exclusively for the focal ratio rather than focal length. The reason the C14 can get the high focal length it has is because it also has a large aperture, whilst still remaining at that ideal focal ratio. With the 150mm aperture, there is simply not enough light gathering capability to gather smaller details above ~1800mm focal length with your camera in UK seeing conditions. That is why you have to stay at f/12 or so, because above that you are just losing detail and getting a blurry larger image. I would add that 3x the pixel size is a very conservative estimate and that even in the UK when seeing is good you could stretch this to 4x or 5x. 

The benefit of ROI is exactly as you’ve pointed out; smaller files, but also an increased FPS (really important). You should aim for around 3 minutes of data for saturn and jupiter per capture. In these 3 minutes, if you have a smaller ROI and can get higher FPS you end up with significantly more frames. The difference between full resolution and 800x600 I’ve found is around a doubling in frame rate. I tend to get ~18,000 total frames, and at least 11,000 or 12,000 with the planet in frame after PIPP processing given that I am letting it drift across. You should aim for at least 10,000 to work with so when you’re cutting down to the 25% best (or whatever % you see working best) you have enough data to sharpen and process. You won’t see a change in image quality as you’re not using more pixels, just cutting down the wasted pixels of background sky and getting a higher amount of frames as a result. 

It’s definitely strange that your final images are being scaled up. Once I’ve saved the image from registax, I see the exact same size as I have done throughout capture and processing. Are you using PIPP to start with? I would highly recommend it as it crops the planet to whatever size you like and centres all your frames. Perhaps that is the missing step. I would add that last night seeing for me was absolutely god awful, so I had significantly less detail than previous attempts and this could have been the difference between your 150 and 14” results. 

I’ve only just read that your scopes are tracked rather than manual. This helps you IMMENSELY. You should cut down ROI to the smallest you can fit the planet in, so long as your tracking keeps it in frame. A tracked 14” scope should have no issue getting results not far off a C14 set up, so long as you are bringing the f/ratio up to that ideal. 

I’ve certainly struggled with the sharpcap settings, though thankfully I find that they do not make a huge difference. I’ve found good results from gain at anywhere between 250-350 or so, but the ASI224 has very low noise, so I’m not sure how far you can push the 462. Try using 300, make sure your fps is at maximum and set your exposure to where the histogram (scroll down a bit to see it) ends at around 75% of the x axis. 

This paragraph’s going to be a bit of a wall of information but I’ll try my best to be clear. Leaving your gain at around 300, and the exposure to where the histogram is at 75%, see what FPS you get when recording. FPS is limited by exposure time and the speed of your laptop (in short). If you find that lowering the exposure increases the FPS, then you’ll want to lower the exposure and increase the gain until your histogram is back at 75%. If you find that there is no change, your laptop speed is the limiting factor, and you can get away with increasing the exposure and lowering the gain (less noise). I would aim for exposures at 3ms or less though, as the shorter exposures cut through seeing better. You basically want the combination of the fastest FPS, lowest exposure, and gain to match an exposure resulting in a 75% histogram (but too high gain will result in extreme noise, so there is a sweet spot between gain and exposure that you will find from experimenting). 

 

Apologies that these two responses have been huge walls of text, but I’m still learning myself and don’t have the understanding yet to put it into concise paragraphs. All that aside, I hope to see your images with the 14” once you’ve got things nailed down as I’m sure they’ll be phenomenal! 

 

[johnturley]

On 20/08/2022 at 16:04, sorrimen said:

Interesting outcomes. The reason the larger pixel size may be preferred in this case is that it allows your ideal focal ratio to be higher. I’m not sure if there’s a slight misunderstanding, but I’ll try and clarify further just in case. You want to be aiming exclusively for the focal ratio rather than focal length. The reason the C14 can get the high focal length it has is because it also has a large aperture, whilst still remaining at that ideal focal ratio. With the 150mm aperture, there is simply not enough light gathering capability to gather smaller details above ~1800mm focal length with your camera in UK seeing conditions. That is why you have to stay at f/12 or so, because above that you are just losing detail and getting a blurry larger image. I would add that 3x the pixel size is a very conservative estimate and that even in the UK when seeing is good you could stretch this to 4x or 5x. 

The benefit of ROI is exactly as you’ve pointed out; smaller files, but also an increased FPS (really important). You should aim for around 3 minutes of data for saturn and jupiter per capture. In these 3 minutes, if you have a smaller ROI and can get higher FPS you end up with significantly more frames. The difference between full resolution and 800x600 I’ve found is around a doubling in frame rate. I tend to get ~18,000 total frames, and at least 11,000 or 12,000 with the planet in frame after PIPP processing given that I am letting it drift across. You should aim for at least 10,000 to work with so when you’re cutting down to the 25% best (or whatever % you see working best) you have enough data to sharpen and process. You won’t see a change in image quality as you’re not using more pixels, just cutting down the wasted pixels of background sky and getting a higher amount of frames as a result. 

It’s definitely strange that your final images are being scaled up. Once I’ve saved the image from registax, I see the exact same size as I have done throughout capture and processing. Are you using PIPP to start with? I would highly recommend it as it crops the planet to whatever size you like and centres all your frames. Perhaps that is the missing step. I would add that last night seeing for me was absolutely god awful, so I had significantly less detail than previous attempts and this could have been the difference between your 150 and 14” results. 

I’ve only just read that your scopes are tracked rather than manual. This helps you IMMENSELY. You should cut down ROI to the smallest you can fit the planet in, so long as your tracking keeps it in frame. A tracked 14” scope should have no issue getting results not far off a C14 set up, so long as you are bringing the f/ratio up to that ideal. 

I’ve certainly struggled with the sharpcap settings, though thankfully I find that they do not make a huge difference. I’ve found good results from gain at anywhere between 250-350 or so, but the ASI224 has very low noise, so I’m not sure how far you can push the 462. Try using 300, make sure your fps is at maximum and set your exposure to where the histogram (scroll down a bit to see it) ends at around 75% of the x axis. 

This paragraph’s going to be a bit of a wall of information but I’ll try my best to be clear. Leaving your gain at around 300, and the exposure to where the histogram is at 75%, see what FPS you get when recording. FPS is limited by exposure time and the speed of your laptop (in short). If you find that lowering the exposure increases the FPS, then you’ll want to lower the exposure and increase the gain until your histogram is back at 75%. If you find that there is no change, your laptop speed is the limiting factor, and you can get away with increasing the exposure and lowering the gain (less noise). I would aim for exposures at 3ms or less though, as the shorter exposures cut through seeing better. You basically want the combination of the fastest FPS, lowest exposure, and gain to match an exposure resulting in a 75% histogram (but too high gain will result in extreme noise, so there is a sweet spot between gain and exposure that you will find from experimenting). 

 

Apologies that these two responses have been huge walls of text, but I’m still learning myself and don’t have the understanding yet to put it into concise paragraphs. All that aside, I hope to see your images with the 14” once you’ve got things nailed down as I’m sure they’ll be phenomenal! 

 

Thanks for more detailed information.

I used to use PIPP when doing planetary imaging with my Canon 6D full frame digital SLR, mainly because the AVI files produced by the Canon would not load directly into Registax, so they needed to be pre-processed in PIPP. With the ZWO ASI 462,, the AVI files do load directly into Registax, so I didn't see any need to pre-process them in PIPP.

Since yesterday however I tried doing this with some of the Sharcap captures from Friday night, also enlarging the image in PIPP, and the settings optimised for planetary movie (AVI) images, and then going into Registax. I however couldn't see any improvement to the quality of the images, and although an enlarged image was visible when processing in Registax, it made no difference to the size of the saved final image. In addition the PIPP pre-processed imaged took significantly longer to Align and Stack in Registax, and I do have a fairly fast laptop with an i7 processor and 16GB of RAM.

It sounds though like I've been not collecting sufficient frames, generally I've set the total frames setting to around 2,000, and the exposure to around 5ms, maybe I should try increasing the frame rate to around 10,000 or more. 

I've looked at a few YouTube videos on Sharpcap, but not found a good one so far, one for showed the user reducing the capture area at the beginning, but not,as you have done, giving any explanation as to why he was doing this. None I've seen so far give much information regarding what are the recommended settings in Sharpcap, can you by any chance recommend a good one.

I must admit that I've never looked at the Histogram while in Sharpcap, and neither have any of the YouTube videos I've seen mentioned it, should I be aiming adjusting the settings such that the graph goes about 75%  of the way across the field. 

Something else I've thought of, do you set the 'Colour Space' to RGB24 (I thought that you would need this to get colour images), rather than RAW8 or RAW16, it's just that someone mentioned RAW8 in another thread. 

Also someone posted that you could enlarge the image a bit by using the 1.5 Drizzle function, in Registax, but when I tried this the imaged 'disappeared' after stacking. 

Many thanks

John

 

Edited August 21, 2022 by johnturley

[Sunshine]

Those are amazing! untracked dob you say? i'm inspired!

[sorrimen]

4 hours ago, johnturley said:

Thanks for more detailed information.

I used to use PIPP when doing planetary imaging with my Canon 6D full frame digital SLR, mainly because the AVI files produced by the Canon would not load directly into Registax, so they needed to be pre-processed in PIPP. With the ZWO ASI 462,, the AVI files do load directly into Registax, so I didn't see any need to pre-process them in PIPP.

Since yesterday however I tried doing this with some of the Sharcap captures from Friday night, also enlarging the image in PIPP, and the settings optimised for planetary movie (AVI) images, and then going into Registax. I however couldn't see any improvement to the quality of the images, and although an enlarged image was visible when processing in Registax, it made no difference to the size of the saved final image. In addition the PIPP pre-processed imaged took significantly longer to Align and Stack in Registax, and I do have a fairly fast laptop with an i7 processor and 16GB of RAM.

It sounds though like I've been not collecting sufficient frames, generally I've set the total frames setting to around 2,000, and the exposure to around 5ms, maybe I should try increasing the frame rate to around 10,000 or more. 

I've looked at a few YouTube videos on Sharpcap, but not found a good one so far, one for showed the user reducing the capture area at the beginning, but not,as you have done, giving any explanation as to why he was doing this. None I've seen so far give much information regarding what are the recommended settings in Sharpcap, can you by any chance recommend a good one.

I must admit that I've never looked at the Histogram while in Sharpcap, and neither have any of the YouTube videos I've seen mentioned it, should I be aiming adjusting the settings such that the graph goes about 75%  of the way across the field. 

Something else I've thought of, do you set the 'Colour Space' to RGB24 (I thought that you would need this to get colour images), rather than RAW8 or RAW16, it's just that someone mentioned RAW8 in another thread. 

Also someone posted that you could enlarge the image a bit by using the 1.5 Drizzle function, in Registax, but when I tried this the imaged 'disappeared' after stacking. 

Many thanks

John

 

For future processing, I would personally recommend Autostakkert for stacking rather than registax. Seems to be that separating each stage of processing into a respective program dedicated to that stage works best (i.e. align in PIPP, stack in Autostakkert, sharpen registax, aesthetics photoshop). That said, lots of people leave PIPP out and it’s main function for me is getting rid of frames where the planet isn’t visible (not an issue with tracking). 

Your number of frames is absolutely going to be what’s holding you back. At that long of an exposure with that few frames you’re barely cutting through the seeing at all. Getting 10,000 or even better 15,000-20,000 will give you instant improvements and will make all the other changes (stacking in AS!3 etc.) much more noticeable. 

I’ve not seen any sharpcap tutorials. I just found some cloudynights posts with exemplar settings, and experimented from there. Gotta remind you I’m very much still learning myself so settings are still somewhat new to me. Yes, 75% means the ending limbs are around 75% the way across the graph. I don’t know much about the histogram and admittedly haven’t looked at it much yet either. I tend to adjust the settings to the point that I have some things visible to focus on, but normally leave it quite dim so that I can get more frames and less noise. I wouldn’t worry too much about 75%, more so that it’s not super overexposed or underexposed (50-85% should be okay). In autostakkert, you should select ‘Normalise stack’ to 75%. This means that everything you process through there will have its histogram adjusted to 70%, regardless of what you captured it at. Super helpful for keeping results consistent. Settings-wise, I wouldn’t bother too much with finding tutorials. Set your gain at ~300, exposure to somewhere where you can see some dim features to focus with (or use histogram) and FPS uncapped. Play around from there and you’ll soon come to grips with it, I assure you. 

Capturing in RAW is essential. RAW8 is good for planetary. Capturing 15,000 frames in RAW8 compared to 2,000 in RGB24 is going to be such a huge improvement. 

I’ve tried drizzling, but think it’s only really useful if you’ve got sufficient aperture. With my captures it just pixelates and blurs without improving anything. Not necessary to play with for now.

Try these suggestions out. I think even with the 150 you should get something not super far off my results with good seeing, even if it’s a bit smaller. Would definitely recommend getting the 14” out if you can instead though. Barlowed 14”, asi462, 15,000 frames (limited to 3 minute video), 75% histogram and even basic sharpening I can’t imagine you’ll get anything less than really phenomenal results compared to mine and in general. 

Please pm me your results! 

[CraigT82]

Regarding exposure and gain settings for capture, there is a great feature is sharpcap (pro - well worth £12 imo) called smart histogram. If you do a sensor analysis prior to using it it will use that analysis to give you a live readout of your SNR when you mouseover the histo peak. 
 

By altering your exposure and gain you can see what gives you the best SNR. (Hint: the best SNR values come from longer exposure and lower gain). The gotcha here though is that you have an upper limit on your exposure length which is the seeing. In good seeing you can use longer exposures and in poor seeing you will be forced to use shorter ones. 

The idea really is to use the longest exposures the seeing will let you get away with. And don’t worry about then increasing the gain to get the histogram up to 75% or whatever, that doesn’t matter. Keep the gain low and If the image is dim then that’s fine, you can brighten it later in post processing (eg. By using the ‘normalise’ function in Autostakkert).  You don’t want to go too low with the gain though as if the noise on the image is very low that can cause issues further down the line after stacking - the stack may retain a lower bit depth which can lead to artefacts after using wavelets.
 

Edit: Just thought I should add - at the risk of overcomplicating things - that it’s the SNR of the final stack that we are concerned about as that is what we will be sharpening. It is generally good to to aim for higher SNR in your sub-exposures, but it must be considered that although shorter exposures would have a lower SNR you may be able to stack a lot more of them into the final image, due to the faster frame rates they bring,   thereby overcoming the initially lower SNR of the individual subs. What really matters is the total exposure time of the final image, with the longer the better, and that’s where winjupos comes in.
 

 

Edited August 22, 2022 by CraigT82

[johnturley]

19 minutes ago, CraigT82 said:

Regarding exposure and gain settings for capture, there is a great feature is sharpcap (pro - well worth £12 imo) called smart histogram. If you do a sensor analysis prior to using it it will use that analysis to give you a live readout of your SNR when you mouseover the histo peak. 
 

By altering your exposure and gain you can see what gives you the best SNR. (Hint: the best SNR values come from longer exposure and lower gain). The gotcha here though is that you have an upper limit on your exposure length which is the seeing. In good seeing you can use longer exposures and in poor seeing you will be forced to use shorter ones. 

The idea really is to use the longest exposures the seeing will let you get away with. And don’t worry about then increasing the gain to get the histogram up to 75% or whatever, that doesn’t matter. Keep the gain low and If the image is dim then that’s fine, you can brighten it later in post processing (eg. By using the ‘normalise’ function in Autostakkert).  You don’t want to go too low with the gain though as if the noise on the image is very low that can cause issues further down the line after stacking - the stack may retain a lower bit depth which can lead to artefacts after using wavelets.
 

 

 

Thanks for the info, I note that you use a small capture area (640 x 480) and RAW 8 rather than RGB 24, what is the advantage, doesn't using RAW 8 give you a black and white image.

John 

[CraigT82]

The advantage of using RAW mode is smaller capture files and higher frame rates.

The camera will always capture colour information, and when set in RGB24 mode it will debayer the images itself and write a 24 bit colour file to the hard drive (8 bits red, 8 blue and 8 green = 24 bits). Because these files 3x larger in size the capture speed will slow and you'll get a much reduced FPS.  When set in RAW8 mode the camera doesn't do any debayering, just sends the raw data to the hard drive as a B&W file but it does contain colour information locked up in the bayer pattern.  Sharpcap will see only a B&W image too because it doesn't do the debayering either (although you can set it to debayer the preview image if you want to - some find it easier to focus with a colour image).  This B&W 8 bit capture then needs to be debayered to produce a colour image, you can do this in PIPP but AS3 does it automatically as part of the stacking process.

[johnturley]

Thanks for the info, I can understand now why some people use PIPP as well as Registax.

John

[CraigT82]

You don't have to use either, I don't.

My workflow is Firecapture (capture) > Autostakkert 3 (registration and stacking) > Astrourface (Sharpening) > Affinity photo or Gimp (finishing).

PIPP is still a very handy bit of software though and I do use it for some things, usually to automatically reject frames without a planet or an incomplete planet due to windy conditions as AS3 can struggle with those frames.

[johnturley]

1 hour ago, CraigT82 said:

You don't have to use either, I don't.

My workflow is Firecapture (capture) > Autostakkert 3 (registration and stacking) > Astrourface (Sharpening) > Affinity photo or Gimp (finishing).

PIPP is still a very handy bit of software though and I do use it for some things, usually to automatically reject frames without a planet or an incomplete planet due to windy conditions as AS3 can struggle with those frames.

Been struggling to learn Sharpcap, PIPP, and Registax over the last 12 months, don't think I can face learning 3 or 4 completely new programs, but may give Autostakkert a try, as quite a few people seem to prefer it to Registax for stacking.

Not sure however whether you can use it in conjunction with Registax, can you go straight into the Wavelet function, skipping stacking, if pre stacked in Autostakkert 3.

John 

Edited August 22, 2022 by johnturley

[sorrimen]

Thanks Craig for the info, smart histogram looks like an incredibly useful tool. 

Would certainly recommend adding in Autostakkert, John. The workflow there is Open file -> press analyse -> add align points (can do this automatically) -> stack (set your % of best frames, and tick normalise stack). If you can tackle registax, autostakkert will be a breeze. 

PIPP, as Craig mentioned, isn’t necessary. It’s very useful for untracked as it gets rid of the frames that have no planet present, but with a tracked set up this is a non-issue and autostakkert should do just fine on its own.

[CraigT82]

John I promise you will get better results by stacking in Autostakkert 3 than you will from registax! It’s well worth learning. As sorrimen says it’s not that involved. 
 

You can take the stacked tiffs from AS3 and load them into registax to apply wavelets 

[Astro_Dad]

Enjoying this very informative thread on planetary AP. I’m largely observational but I’ve dabbled previously with a ZWO and posted some early results here, but I’m planning on having anther go. I’ve just today returned a Celestron Skyris 132c cam as couldn’t get it to work at all with Windows 10 (running in Parallels on a Mac). Several drivers tried but no success. I’m going to replace with another ZWO - probably a 224. Keen to try some “basic” untracked with my 10” Dob having been inspired by the excellent results achieved by @sorrimen with his Dob. Very useful reading here the various tips and tricks. Thanks. 

[astronymonkey]

On 21/08/2022 at 14:54, Sunshine said:

Those are amazing! untracked dob you say? i'm inspired!

Me too! Very impressive.... arrgh ...note to self , you can not afford to get into astrophotography