Mars August 10th

[neil phillips]

59 minutes ago, johnturley said:

Thanks Neil

I've tried reprocessing one of my images in Registax using the Drizzle function, and although it gave a larger image while in Registax, when I saved it back to my laptop as a JPEG file, the image size was exactly the same, am I missing something here.

I gather you can also increase the image size in Sharpcap while imaging by reducing the capture area the full 1936 x 1096, but surely this would reduce the quality of the image, so not sure why you would want to do this, surely better to use an optical method for increasing the image size, such as a Barlow/Powermate. I am finding however that my 5x Powermate is too great for Jupiter and Saturn, giving a large blurred image, and have got better results from an old Meade 2x Barlow (may replace it with the 2.5x Pwermate) , although the 5x Powermate might be ok for Mars, where you get a very small, but very bright image, and I notice from your website that you have used a 5x Powermate for some Mars images.  

One of the reasons why I tend to use the Esprit 150 for planetary imaging rather than the Newtonian  (apart from the fact that the Esprit gives sharper images most of the time) is because of the mounting arrangement in my observatory shed. The Esprit is mounted piggyback on my 14 in Newtonian, which is in a massive fork mount made by Rob Miller of Asto Systems (Luton) in the 1980's, but does suffer from the problem of not being able to clamp the polar axis. The focusing mount of the Esprit is situated close to centre of gravity of the mount, so not too much of a problem, but adding heavy equipment to the Newtonian focus can result in things swinging out of control, and also the USB cable to the ZWO 462 might not be long enough. I have however in previous years taken some reasonably good planetary images through the Newtonian using eyepiece projection with a Canon 6D Digital SLR Camera (see attached image of Mars from September 2020 showing Syrtis Major and the SPC).

John 

That is very strange never heard of a drizzle 1.5x coming out the same size after saving. i would suggest process one with drizzle and one with out. then look at the file size of both captures by right clicking the drizzle should be bigger. i can not think why it would not ? Drizzle is generally only useful for under sampled images. The reason i use it. It changes the way the wavelets respond in registax. That i personally happen to like. Chris go and Anthony wesley seem to think drizzle can also produce a more accurate stack on lunar. Not sure if thats correct or not. But ive heard Chris go say that. 

As far as barlow power is concerned You should really try to get a optimum sampling rate. Which will vary depending on the camera used. Here is a link Not sure how useful this is, But it certainly should show you the different effects of sampling rates astronomy.tools

Cheers Nice Mars image btw. 

[johnturley]

1 hour ago, neil phillips said:

 

As far as barlow power is concerned You should really try to get a optimum sampling rate. Which will vary depending on the camera used. Here is a link Not sure how useful this is, But it certainly should show you the different effects of sampling rates astronomy.tools

 

Thanks for the information Neil

I had a look at astronomy.tools , and to my surprise it suggested that under OK seeing in order to achieve the optimum 0.67 - 2" /Pixel with the Esprit 150, I shouldn't be using any Barlow at all, in fact would be better with a focal reducer !, which would result in useless tiny images - weird. 

It also it indicated that I would get nearer to the optimum by using  2 x 2 rather than 1 x 1 CCD Binning, do you have any views on this.

John  

Edited August 11, 2022 by johnturley

[neil phillips]

13 hours ago, johnturley said:

Thanks for the information Neil

I had a look at astronomy.tools , and to my surprise it suggested that under OK seeing in order to achieve the optimum 0.67 - 2" /Pixel with the Esprit 150, I shouldn't be using any Barlow at all, in fact would be better with a focal reducer !, which would result in useless tiny images - weird. 

It also it indicated that I would get nearer to the optimum by using  2 x 2 rather than 1 x 1 CCD Binning, do you have any views on this.

John  

Yeah i havent really looked at that much. That does sound silly. What i said before still counts aim for F11 F12 with your Esprit and you should be fine with that camera 

[U Cyg]

Nice detail Neil. 

Angie

[geoflewis]

On 11/08/2022 at 13:11, johnturley said:

Thanks for the information Neil

I had a look at astronomy.tools , and to my surprise it suggested that under OK seeing in order to achieve the optimum 0.67 - 2" /Pixel with the Esprit 150, I shouldn't be using any Barlow at all, in fact would be better with a focal reducer !, which would result in useless tiny images - weird. 

It also it indicated that I would get nearer to the optimum by using  2 x 2 rather than 1 x 1 CCD Binning, do you have any views on this.

John  

Hi John, I believe that the astronomy tools recommendation is for DSO imaging; it's a completely different story for planetary. The general rule of thumb for planetary is to set the focal ratio to around 5x the pixel size of the camera (in microns) in good conditions, 7x the pixel size in excellent conditions - from the uk you can pretty much ignore the x7 as seeing is rarely, if ever, that good. I tend to the view that x3 to x5 is a good working range. Traditionally I've used my C14 with a x2 Powermate, but with the 2.9 micro pixels of my ASI 290mm camera x5 would be ~F15, so it's questionable whether x2 Powermate is too much magnification and I should just go with the native F11 of the scope. I did experiment with binning the camera back in 2020 and had some good results, but the jury is still out. I haven't done any planetary imaging yet this year, so will probably experiment some more, when I get around to it.

19 hours ago, neil phillips said:

What i said before still counts aim for F11 F12 with your Esprit and you should be fine with that camera

Neil's suggestion of F11/F12 sounds very reasonable to me.

Good luck.

Edited August 12, 2022 by geoflewis

[neil phillips]

10 hours ago, U Cyg said:

Nice detail Neil. 

Angie

Thanks Angie

[stuy]

Fantastic Neil 

[johnturley]

17 hours ago, geoflewis said:

Hi John, I believe that the astronomy tools recommendation is for DSO imaging; it's a completely different story for planetary. The general rule of thumb for planetary is to set the focal ratio to around 5x the pixel size of the camera (in microns) in good conditions, 7x the pixel size in excellent conditions - from the uk you can pretty much ignore the x7 as seeing is rarely, if ever, that good. I tend to the view that x3 to x5 is a good working range. Traditionally I've used my C14 with a x2 Powermate, but with the 2.9 micro pixels of my ASI 290mm camera x5 would be ~F15, so it's questionable whether x2 Powermate is too much magnification and I should just go with the native F11 of the scope. I did experiment with binning the camera back in 2020 and had some good results, but the jury is still out. I haven't done any planetary imaging yet this year, so will probably experiment some more, when I get around to it.

Neil's suggestion of F11/F12 sounds very reasonable to me.

Good luck.

Hi Geoff

Note that you have a C14, I can now understand why some (including Damien Peach I think), regard this as being the ideal instrument for planetary imaging, as with its native focal length of nearly 4,000 mm, it will provide decent sized images of Jupiter and Saturn without requiring and further enlargement with a barlow lens, or eyepiece projection, although I would imagine that you would require at least a 2x Barlow to give a decent sized image for Mars.

I am fairly new to planetary imaging with a dedicated planetary camera (in my case ZWO ASI 462), although I have done a bit of lunar and planetary imaging over the years, first with a film SLR, and then a digital SLR using eyepiece projection to get a decent sized image. I am finding however that there is much bigger learning curve associated with a planetary camera, and moreover some of the information out their on websites, such as Astronomy Tools, is either misleading or inaccurate. 

I thought (perhaps mistakenly) that because my Esprit 150 gives sharper visual images 90% of the time than my 14in Newtonian, it would give better results regarding planetary images, but maybe not. With the Esprit 150, I need at least f15 (2x Barlow) to give a decent sized image for Jupiter and Saturn, f20 (3x Barlow) would be better, but I found with f35 (5X Powermate) the image, although a decent size, was too dim and blury, and I couldn't improve it that much with processing in Registax and Lightroom. Talking about large focal ratios, I gather in the days of film SLR's using eyepiece projection, it was commonplace to aim for focal ratios in the region of f50 to f80.

I did a bit of experimenting with Jupiter last night to try to get a larger image, including reducing the capture area of the ZWO 462 from the native 1936 x 1096 (as suggested in a Youtube video I've seen), but it didn't make any difference to the size, it just gave a grainier image (so don't understand why you would want to do this). I also tried changing the CCD Binning rate from 1 x 1 to 2 x 2 (as suggested in Astronomy Tools), but this just gave a brighter and more grainier image. I also tried the 'drizzle' function in Registax, but again this did not seem to help, and I found that after selecting drizzle and then stacking, the image sometimes disappeared altogether.

Another reason (as I mentioned in some other posts) for using the Esprit, is that the the focussing mount is close to the centre of gravity of the fork mount on which it is piggybacked, reducing balance issues. I will however over the next few weeks try some planetary imaging through the 14in, and see how it compares, with a 2x Barlow, this would give an effective focal length of around 3,600mm and focal ratio of f10, close to that of a C14. As Jupiter moves into a more southerly position in coming weeks, this will reduce the balance problems inherent in the fork mount. 

John

 

 

[neil phillips]

3 hours ago, johnturley said:

Hi Geoff

Note that you have a C14, I can now understand why some (including Damien Peach I think), regard this as being the ideal instrument for planetary imaging, as with its native focal length of nearly 4,000 mm, it will provide decent sized images of Jupiter and Saturn without requiring and further enlargement with a barlow lens, or eyepiece projection, although I would imagine that you would require at least a 2x Barlow to give a decent sized image for Mars.

I am fairly new to planetary imaging with a dedicated planetary camera (in my case ZWO ASI 462), although I have done a bit of lunar and planetary imaging over the years, first with a film SLR, and then a digital SLR using eyepiece projection to get a decent sized image. I am finding however that there is much bigger learning curve associated with a planetary camera, and moreover some of the information out their on websites, such as Astronomy Tools, is either misleading or inaccurate. 

I thought (perhaps mistakenly) that because my Esprit 150 gives sharper visual images 90% of the time than my 14in Newtonian, it would give better results regarding planetary images, but maybe not. With the Esprit 150, I need at least f15 (2x Barlow) to give a decent sized image for Jupiter and Saturn, f20 (3x Barlow) would be better, but I found with f35 (5X Powermate) the image, although a decent size, was too dim and blury, and I couldn't improve it that much with processing in Registax and Lightroom. Talking about large focal ratios, I gather in the days of film SLR's using eyepiece projection, it was commonplace to aim for focal ratios in the region of f50 to f80.

I did a bit of experimenting with Jupiter last night to try to get a larger image, including reducing the capture area of the ZWO 462 from the native 1936 x 1096 (as suggested in a Youtube video I've seen), but it didn't make any difference to the size, it just gave a grainier image (so don't understand why you would want to do this). I also tried changing the CCD Binning rate from 1 x 1 to 2 x 2 (as suggested in Astronomy Tools), but this just gave a brighter and more grainier image. I also tried the 'drizzle' function in Registax, but again this did not seem to help, and I found that after selecting drizzle and then stacking, the image sometimes disappeared altogether.

Another reason (as I mentioned in some other posts) for using the Esprit, is that the the focussing mount is close to the centre of gravity of the fork mount on which it is piggybacked, reducing balance issues. I will however over the next few weeks try some planetary imaging through the 14in, and see how it compares, with a 2x Barlow, this would give an effective focal length of around 3,600mm and focal ratio of f10, close to that of a C14. As Jupiter moves into a more southerly position in coming weeks, this will reduce the balance problems inherent in the fork mount. 

John

 

 

John the reason people reduce the capture area. Has nothing to do with the size of a planetary image. The reason we do this is two fold. First the file size is much reduced. So if you wanted to take a lot of images. it is not going to wipe your hard drive out of space in twenty minuets.

Second if you do not reduce your capture area or ROI ( region of interest ) you will not be able to run the camera at higher frame rates. You will notice on the manufacturer webpage. It shows the frame rates of the different capture areas for example. At full resolution. in 12  bit your limited to 63.9 frames per second. But at 320x240 capture area. Again in 12 bit mode. You would be at 276.8 frames per second. These frame rates are over twice as fast in 10 bit mode. So you can see the reason has nothing to do with the size of the image. But everything to do with file size and frame rate. Binning can be useful for when your oversampled if doing planetary imaging It will improve the signal to noise ratio in such situations that you are oversampled.. Again it has nothing to do with image size per se in the context you have been thinking. That is not the reason people would use binning. 

Here you can see the zwo specs frame rates per capture area.

USB3.0 MAX FPS (12bit/10bit)

• 1936*1096 63.9fps 136.1fps
• 1920*1080 64.8fps 138.1fps
• 1280*720 96.5fps 205.6fps
• 640*480 143.1fps 305fps
• 400*400 170.6fps 363.5fps
• 320*240 276.8fps 589.6fps

But don't forget frame rates are also proportional to the exposure being used. If the exposure is too long. it doesn't matter what capture area you have chosen. it will not run at full speed unless the exposure is proportional to it. As a example with my QHY camera if I have the exposure set at 1/125secs (8.00ms) Using a capture area of 640x480. ( i often use this ) I can get a frame rate of around 125 frames per second. Conversely If I set the exposure to 1/250s (4.00ms) I can get 250 frames per second. with my preferred capture area of 640x480.

So again frame rate is dependent on capture area. And exposure length.

You will not get images like I have posted recently with your Esprit. Good as it is. It is just not good enough to produce planetary images like these unfortunately. Most people buying those telescopes are likely not buying it for that anyway.  However your 14 " Newtonian is a different matter. Properly cooled and collimated it is possible to get better images than what i have posted recently.

Depending how good the optics are. If I was using your esprit 150. To image Jupiter. Then switched to the 14" Newtonian. under good seeing. it would leave the little Esprit in the dust. To not put too finer point on it. It would utterly destroy it as a planetary telescope, imaging under good seeing. No contest game over.

If you want better planetary images. Collimate the 14" to perfection. Cool it properly. Get a correct sample rate with the camera that is adequate. (Do that and your image size will be fine )  And your images could be better than what I have posted recently. As your scope is far larger John.

Good luck. If you want to learn more. I am sure there is a ton of information about all this. Both on the net. Or youtube. And or if you want some specific information start a thread or threads on here. Many are very knowledgeable on here. Who I am sure can also help get you up to speed.  Again good luck

Edited August 13, 2022 by neil phillips

[neil phillips]

3 hours ago, stuy said:

Fantastic Neil 

Cheers Stuy

[johnturley]

On 13/08/2022 at 19:11, neil phillips said:

John the reason people reduce the capture area. Has nothing to do with the size of a planetary image. The reason we do this is two fold. First the file size is much reduced. So if you wanted to take a lot of images. it is not going to wipe your hard drive out of space in twenty minuets.

Second if you do not reduce your capture area or ROI ( region of interest ) you will not be able to run the camera at higher frame rates. You will notice on the manufacturer webpage. It shows the frame rates of the different capture areas for example. At full resolution. in 12  bit your limited to 63.9 frames per second. But at 320x240 capture area. Again in 12 bit mode. You would be at 276.8 frames per second. These frame rates are over twice as fast in 10 bit mode. So you can see the reason has nothing to do with the size of the image. But everything to do with file size and frame rate. Binning can be useful for when your oversampled if doing planetary imaging It will improve the signal to noise ratio in such situations that you are oversampled.. Again it has nothing to do with image size per se in the context you have been thinking. That is not the reason people would use binning. 

Here you can see the zwo specs frame rates per capture area.

USB3.0 MAX FPS (12bit/10bit)

• 1936*1096 63.9fps 136.1fps
• 1920*1080 64.8fps 138.1fps
• 1280*720 96.5fps 205.6fps
• 640*480 143.1fps 305fps
• 400*400 170.6fps 363.5fps
• 320*240 276.8fps 589.6fps

But don't forget frame rates are also proportional to the exposure being used. If the exposure is too long. it doesn't matter what capture area you have chosen. it will not run at full speed unless the exposure is proportional to it. As a example with my QHY camera if I have the exposure set at 1/125secs (8.00ms) Using a capture area of 640x480. ( i often use this ) I can get a frame rate of around 125 frames per second. Conversely If I set the exposure to 1/250s (4.00ms) I can get 250 frames per second. with my preferred capture area of 640x480.

So again frame rate is dependent on capture area. And exposure length.

You will not get images like I have posted recently with your Esprit. Good as it is. It is just not good enough to produce planetary images like these unfortunately. Most people buying those telescopes are likely not buying it for that anyway.  However your 14 " Newtonian is a different matter. Properly cooled and collimated it is possible to get better images than what i have posted recently.

Depending how good the optics are. If I was using your esprit 150. To image Jupiter. Then switched to the 14" Newtonian. under good seeing. it would leave the little Esprit in the dust. To not put too finer point on it. It would utterly destroy it as a planetary telescope, imaging under good seeing. No contest game over.

If you want better planetary images. Collimate the 14" to perfection. Cool it properly. Get a correct sample rate with the camera that is adequate. (Do that and your image size will be fine )  And your images could be better than what I have posted recently. As your scope is far larger John.

Good luck. If you want to learn more. I am sure there is a ton of information about all this. Both on the net. Or youtube. And or if you want some specific information start a thread or threads on here. Many are very knowledgeable on here. Who I am sure can also help get you up to speed.  Again good luck

Neil

Thanks for your tips regarding imaging, very useful.

I think someone previously replied to a earlier post of mine, from last year I think, about my images coming out too small, suggesting that I should reduce the capture area, but as you say, and as I’ve found out, it doesn’t make any difference to the size. 

In addition to reducing the capture area, I take it you recommend using 10 bit rather than 12 bit capture mode in Sharpcap to increase the maximum frame rate, although looking at the spec of the ZWO ASI 462 I thought that it was limited to a maximum of 136 fps, and that the maximum of 589.6 just was the potential maximum of a USB 3.0 cable in 10 bit mode. Also I thought that you would need to increase the exposure time to provide a sufficiently bright image, which will also reduce the maximum fps rate. You are certainly right about using the full capture area using a lot of disc space, the imaging I did last week (before I deleted some files) used up over 256 GB of disc space.

I’ve looked at a few more Youtube videos on imaging and processing, some useful, others not so useful. I notice that some think that Bahtinov masks for focusing are the best thing since sliced bread, others think that they should be avoided like the plague for planetary imaging.

Interestingly several of the Youtube videos, suggest that you should use a combination of PIPP, AutoStakkert, and Registax for processing, making the whole process more complicated and lengthy. When I did some imaging in 2020 with my Canon 6D (before I purchased the ZWO 462), I needed to use PIPP as the AVI files produced by the Canon 6D would not load directly into Registax, but with the ZWO its not a problem, so why use PIPP as well, must be some reason. However I’ve taken some of my original AVI files from Sharcap Captures and pre-processed them in PIPP prior to Registax, however I couldn’t notice much difference with the final images, apart from the fact that they took about 5x longer to process in Registax if pre-processed in PIPP.  

I’m surprised you regard medium sized refractors such as the Esprit 150 as unsuitable for planetary  imaging, as so may people rave about the supposed superiority of refractors over Newtonians for viewing planets visually, in particular the owners of 3-4 in refractors from a well-known Japanese  manufacturer, claiming that there scopes will out-perform others of much larger aperture, and allow magnifications (visually) up to 100x or even 120x per in of aperture. Maybe as you say, it’s a totally different ball game when it comes to planetary imaging.

 My 14 in Reflector, which I have owned since 1984, has always provided reasonably good views of planets,  and under good conditions could easily outperform an early (pre Starfire) Astro Physics 6in f8 Refractor that I used to own. The Esprit 150 is definitely superior to the AP scope (gasps of horror from AP purists), both in terms of colour correction and sharpness of the view. Only on rare occasions has the 14in been able to provide superior visual views of planets to the Esprit, although things like the colour of the GRS, shadow transits of Jovian satellites, and as would be expected, the faint satellites of Saturn show up better in the larger reflector.

I did have some doubts as to the quality of the 14in mirror (which incidentally is made out of Duran 50 low expansion glass), so this year I took it for testing to John Nichol of Nichol Optics, and I was able to view the Ronchi test myself. John was of the opinion that it was around 1/8 wave, and that he wouldn’t be able to improve it such that I would notice any difference when viewing. The mirror cell is of an unusual design by Rob Miller, which you are unlikely to see nowadays, such that the bottom end of the tube is oversized, around 20in in diameter to allow good air circulation.

As mentioned, due to the layout in my observatory shed, I need to wait for Jupiter to come round more to the south to enable me to easily attach the ZWO camera, cable and laptop to the Newtonian focus, so I will then see whether it does give superior results. With its longer focal length of around 1800 mm, I should get reasonably sized images of Jupiter and Saturn with a 2-3x Barlow, although I might requite 5x for Mars. In addition the brighter images should allow a higher fps rate.

John

Edited August 15, 2022 by johnturley

[neil phillips]

Yes i would choose frame rate. As the more important consideration. Visual and imaging are two different things. which is why i say the 14" Newtonian will wipe the floor of the refractor. The Newtonian will show more. And have a much brighter image. Large images from long focal length. Will not be impossibly dim. Good as any 6" scope is. it cannot compete with a good 14" for imaging planets. Why do you think all the serious planetary imagers use 14" SCTs. Try getting a good sample rate with the 14" Resampling could be used to increase a small mars later. I have got good results oversampling. Though its probably bad advice to recommend it. So i wont. Again Good luck John. will look out for any images

[geoflewis]

On 13/08/2022 at 19:11, neil phillips said:

John the reason people reduce the capture area. Has nothing to do with the size of a planetary image. The reason we do this is two fold. First the file size is much reduced. So if you wanted to take a lot of images. it is not going to wipe your hard drive out of space in twenty minuets.

Second if you do not reduce your capture area or ROI ( region of interest ) you will not be able to run the camera at higher frame rates. You will notice on the manufacturer webpage. It shows the frame rates of the different capture areas for example. At full resolution. in 12  bit your limited to 63.9 frames per second. But at 320x240 capture area. Again in 12 bit mode. You would be at 276.8 frames per second. These frame rates are over twice as fast in 10 bit mode. So you can see the reason has nothing to do with the size of the image. But everything to do with file size and frame rate. Binning can be useful for when your oversampled if doing planetary imaging It will improve the signal to noise ratio in such situations that you are oversampled.. Again it has nothing to do with image size per se in the context you have been thinking. That is not the reason people would use binning. 

Here you can see the zwo specs frame rates per capture area.

USB3.0 MAX FPS (12bit/10bit)

• 1936*1096 63.9fps 136.1fps
• 1920*1080 64.8fps 138.1fps
• 1280*720 96.5fps 205.6fps
• 640*480 143.1fps 305fps
• 400*400 170.6fps 363.5fps
• 320*240 276.8fps 589.6fps

But don't forget frame rates are also proportional to the exposure being used. If the exposure is too long. it doesn't matter what capture area you have chosen. it will not run at full speed unless the exposure is proportional to it. As a example with my QHY camera if I have the exposure set at 1/125secs (8.00ms) Using a capture area of 640x480. ( i often use this ) I can get a frame rate of around 125 frames per second. Conversely If I set the exposure to 1/250s (4.00ms) I can get 250 frames per second. with my preferred capture area of 640x480.

So again frame rate is dependent on capture area. And exposure length.

You will not get images like I have posted recently with your Esprit. Good as it is. It is just not good enough to produce planetary images like these unfortunately. Most people buying those telescopes are likely not buying it for that anyway.  However your 14 " Newtonian is a different matter. Properly cooled and collimated it is possible to get better images than what i have posted recently.

Depending how good the optics are. If I was using your esprit 150. To image Jupiter. Then switched to the 14" Newtonian. under good seeing. it would leave the little Esprit in the dust. To not put too finer point on it. It would utterly destroy it as a planetary telescope, imaging under good seeing. No contest game over.

If you want better planetary images. Collimate the 14" to perfection. Cool it properly. Get a correct sample rate with the camera that is adequate. (Do that and your image size will be fine )  And your images could be better than what I have posted recently. As your scope is far larger John.

Good luck. If you want to learn more. I am sure there is a ton of information about all this. Both on the net. Or youtube. And or if you want some specific information start a thread or threads on here. Many are very knowledgeable on here. Who I am sure can also help get you up to speed.  Again good luck

@johnturley sorry I didn't see you reply earlier, but I really couldn't offer a better explanation than Neil has given above. You should definitely try the 14" Newt for planetary, but I'll add 2 very significant things to keep in mind:

1. You must pay attention to accurate collimation of your scope, this is a critical element to successful planetary imaging. As Neil mentioned your scope needs to be properly cooled and collimated; this is not just a throw away comment, it is essential. I believe Damian checks his scopes collimation at the start of every imaging session.
2. Seeing is everything. There's nothing you can do about that, other than move to somewhere like Barbados, where Damian usually hangs out for Jupiter opposition - at least he did until Covid stopped him travelling. For the last few years Jupiter and Saturn have been very low from UK latitudes, so planetary imaging has been a PITA, but finanly we are seeing higher altitudes, so if seeing is good, then we have a chance.

On 14/08/2022 at 15:06, johnturley said:

Interestingly several of the Youtube videos, suggest that you should use a combination of PIPP, AutoStakkert, and Registax for processing, making the whole process more complicated and lengthy. When I did some imaging in 2020 with my Canon 6D (before I purchased the ZWO 462), I needed to use PIPP as the AVI files produced by the Canon 6D would not load directly into Registax, but with the ZWO its not a problem, so why use PIPP as well, must be some reason. However I’ve taken some of my original AVI files from Sharcap Captures and pre-processed them in PIPP prior to Registax, however I couldn’t notice much difference with the final images, apart from the fact that they took about 5x longer to process in Registax if pre-processed in PIPP.

There will be some variation in the way folks approach processing, e.g. I don't use PIPP, but I do use both AS3! and Registax. I also use FireCapture for capture with a WinJupos file naming capture setting which creates filenames easily readable for WinJupos derotation stacking. I almost always use WinJupos and find it essential for my mono RGB filter stacking, especially for Jupiter where the planet's rotation is very fast.

Some folks argue that very high frames are required (in the multi 100s fps, but it's not my experience and seasoned imagers like Anthony Wesley in Oz suggest that capture is optimised at around 60fps. You definitely need fairly fast capture speeds for lucky imaging to work, but then you also need long enough exposures for the image to be sufficiently bright - it's definitely an area for trial and error. As Neil commented using ROI really makes a huge difference to frame rate speeds and file sizes.

Planetary imaging is most definitely a very different proposition to imaging DSOs, but can be hugely satisfying seeing the planetary surface features change from session to session and for Jupiter, right in front of your eyes as your camera captures the data.

Good luck and have fun.

(PS I'm very envious of your ASI462 - it's on my shopping list to have as a colour, rather mono camera)

Edited August 15, 2022 by geoflewis

[Kon]

On 14/08/2022 at 15:06, johnturley said:

Neil

Thanks for your tips regarding imaging, very useful.

I think someone previously replied to a earlier post of mine, from last year I think, about my images coming out too small, suggesting that I should reduce the capture area, but as you say, and as I’ve found out, it doesn’t make any difference to the size. 

In addition to reducing the capture area, I take it you recommend using 10 bit rather than 12 bit capture mode in Sharpcap to increase the maximum frame rate, although looking at the spec of the ZWO ASI 462 I thought that it was limited to a maximum of 136 fps, and that the maximum of 589.6 just was the potential maximum of a USB 3.0 cable in 10 bit mode. Also I thought that you would need to increase the exposure time to provide a sufficiently bright image, which will also reduce the maximum fps rate. You are certainly right about using the full capture area using a lot of disc space, the imaging I did last week (before I deleted some files) used up over 256 GB of disc space.

I’ve looked at a few more Youtube videos on imaging and processing, some useful, others not so useful. I notice that some think that Bahtinov masks for focusing are the best thing since sliced bread, others think that they should be avoided like the plague for planetary imaging.

Interestingly several of the Youtube videos, suggest that you should use a combination of PIPP, AutoStakkert, and Registax for processing, making the whole process more complicated and lengthy. When I did some imaging in 2020 with my Canon 6D (before I purchased the ZWO 462), I needed to use PIPP as the AVI files produced by the Canon 6D would not load directly into Registax, but with the ZWO its not a problem, so why use PIPP as well, must be some reason. However I’ve taken some of my original AVI files from Sharcap Captures and pre-processed them in PIPP prior to Registax, however I couldn’t notice much difference with the final images, apart from the fact that they took about 5x longer to process in Registax if pre-processed in PIPP.  

I’m surprised you regard medium sized refractors such as the Esprit 150 as unsuitable for planetary  imaging, as so may people rave about the supposed superiority of refractors over Newtonians for viewing planets visually, in particular the owners of 3-4 in refractors from a well-known Japanese  manufacturer, claiming that there scopes will out-perform others of much larger aperture, and allow magnifications (visually) up to 100x or even 120x per in of aperture. Maybe as you say, it’s a totally different ball game when it comes to planetary imaging.

 My 14 in Reflector, which I have owned since 1984, has always provided reasonably good views of planets,  and under good conditions could easily outperform an early (pre Starfire) Astro Physics 6in f8 Refractor that I used to own. The Esprit 150 is definitely superior to the AP scope (gasps of horror from AP purists), both in terms of colour correction and sharpness of the view. Only on rare occasions has the 14in been able to provide superior visual views of planets to the Esprit, although things like the colour of the GRS, shadow transits of Jovian satellites, and as would be expected, the faint satellites of Saturn show up better in the larger reflector.

I did have some doubts as to the quality of the 14in mirror (which incidentally is made out of Duran 50 low expansion glass), so this year I took it for testing to John Nichol of Nichol Optics, and I was able to view the Ronchi test myself. John was of the opinion that it was around 1/8 wave, and that he wouldn’t be able to improve it such that I would notice any difference when viewing. The mirror cell is of an unusual design by Rob Miller, which you are unlikely to see nowadays, such that the bottom end of the tube is oversized, around 20in in diameter to allow good air circulation.

As mentioned, due to the layout in my observatory shed, I need to wait for Jupiter to come round more to the south to enable me to easily attach the ZWO camera, cable and laptop to the Newtonian focus, so I will then see whether it does give superior results. With its longer focal length of around 1800 mm, I should get reasonably sized images of Jupiter and Saturn with a 2-3x Barlow, although I might requite 5x for Mars. In addition the brighter images should allow a higher fps rate.

John

For what is worth and my limited experience, I have the asi462 and I am getting frame rates of 304 on Mars ang Jupiter at a ROI of 640x480 and the exposure is still good enough to see the planet, histogram of 60-80%. Saturn I get close to 200. I did Neptune recently and it dropped to 19.I have an 8" Dob and I am manual tracking in that ROI, it is hard work but I enjoy it.

Regarding size, i use a 2x barlow or 2.5x powermate and the images are good size, unless you are seeking images that feel your monitor then you will resize but lose resolution.

Finally, ask questions and experiment. I have only been imaging for a year or so. Once you have the capture in your hard drive you can try until you get something satisfactory. Play with the capture settings. Post it here and seek feedback. Then try again. Depends on the capture quality every time, you may have to change the processing.

Looking forward to seeing your images.

[johnturley]

15 hours ago, geoflewis said:

 

(PS I'm very envious of your ASI462 - it's on my shopping list to have as a colour, rather mono camera)

FLO currently have the ZWO ASI 462 on offer at £223 (reduced from £253) until the end of August I think.

John