johnturley

Astronomy Now magazine just lists the events visible from the U.K., which simplifies things a lot, and makes them a lot clearer.

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

I think that we can safely say that although you can produce some reasonable planetary images from a digital SLR, they will never be as good as what can be achieved with a dedicated planetary camera.

The attached image of Mars in 2020 was taken through my 14in Newtonian using eyepiece projection with a 9.7 mm Plossl eyepiece, not bad maybe, but nothing like what can be achieved with a dedicated planetary camera. 

I still maintain that there isn't a satisfactory method of producing a decent sized image from the small image you will if get if just using a Barlow to enlarge the image with a full frame, or standard crop frame digital SLR. 

John 

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 

2 hours ago, michael8554 said:

Don't worry too much about the Barlowed image only being a "dot".

Whether you use a large-chip DSLR, or a tiny-chip Planetary camera, the image size on the chip is the same.

The Planetary camera isn't magically producing a larger image.

By the time you've cropped the DSLR image it will be a similar pixel width and height as a planetary camera's output.

Michael

 

I'm surprised about your comment, as its contrary to what a number of people have posted previously, one of the reasons I bought a planetary camera was because with a digital SLR the image scale was far too small unless I used eyepiece projection.

I found that I couldn't do anything much with the resultant tiny images in processing programs such as Registax and Lightroom.

Also if the image is just a dot on the DSLR screen, it will be difficult to achieve correct focus.

John

With a DSLR in order to get decent sized planetary images you will probably need to use eyepiece projection, as a Barlow will generally not provide sufficient amplification for the size of sensor in a DSLR, but they work fine for the smaller sized sensors you get with dedicated planetary cameras.

Eyepiece projection tubes (in which you could fit an eyepiece of your choice) were quite commonplace at one time, but you don't see them advertised much nowadays, alternatively Baader offer adaptors to fit their Hyperion and Morpheus range of eyepieces to enable eyepiece projection.

John  

2 minutes ago, bomberbaz said:

we got a guided tour by what I presume was a astro society of some description. They had half decent gear of I think an 8" dob, 4" frac and they were taking some pictures to show people too. It wasn't cheap, think about 60 euros or maybe more PP but it was a thoroughly enjoyable evening.

1 thing, whatever you decide on wrap up well. It was blooming freezing up there.

Was that by any chance with 'Night Skies Tenerife', we are going to Tenerife next month, and thinking of booking a tour with them. 

Last time we booked a tour with 'Vulcano Teide' which should have included a trip to the Solar Observatory on Tenerife, but they let us down badly, we waited over an hour for a coach that didn't turn up. When I subsequently contacted them, they said that they had cancelled due to bad weather (just sent an email (which I didn't receive), informing me of the cancellation, no attempt to contact me by phone, or the hotel we were staying at). They supposedly cancelled due to bad weather, but we doubted this as couldn't see any problems with the weather on the day. In addition while waiting for their non-existent coach, one for 'Teide by Night' (operated by a different company) pulled up at the same pick up point. Suspect that they had just cancelled due to insufficient numbers to make it viable for them.

John

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 

Nice images especially Mars with its tiny 8 arc second disc, I assume that you use a 2x Barlow or Powermate to get f20, which would be an effective  focal length of about 5,600 mm with your C11.

John 

1 hour ago, bosun21 said:

 

PS:- I didn’t see the tiny Allen key hiding in the corner of the clear plastic bag it was all contained in.

 

 

I've bought several Baader products, and its a bit hit and miss as to whether the Allen key is included. 

On 11/08/2022 at 13:02, yuklop said:

Thanks for the response.

More details on the telescope here:

But I haven't posted all the dimensions. The hole in the primary is huge. I'd estimate about 6 inches, which is a slightly odd feature. The secondary seems oversized too, at about 90mm. I think it'll all be about experimentation and trying to move the secondary forward.

Thanks for the mount comment. It is an amazing mount, and another slightly risky auction site gamble. Turns out it is a late Rob Miller prototype from end of the 80's. More details on that one here if you're interested:

 

The base of the mount looks a bit like a Rob Miller, Astro Systems (Luton) design, similar to that on my fork mounted 14in Newtonian.

John 

On 14/08/2022 at 17:23, knobby said:

The Barlow isn't always a necessity... You want to aim for around 3 x the pixel size of your camera as an F number, maybe up to 5 times if seeing is good.

That will just result in tiny planetary images in the case of a lot of scopes, which you can't do much with in processing, for example with my ZWO ASI 462 the pixel size is just 2.9 um, which would equate to just F9.

John

On 14/08/2022 at 12:43, Rob Astro said:

I need my C9.25 XLT serviced, the ota needs a factory realignment of optical system and a collimation. Is there any dealerships or individuals which can do such work. 

Rother Valley Optics near Sheffield should be able to carry out this work.

John 

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

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

I've also been tempted, but doubt that they will provide the same wide aberration free field that you get with a Nagler.

John  

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

1 hour ago, neil phillips said:

It sounds like your oversampling John You should be around the F11 range so a 1.5x  should get you in the ball park So dont use more than a 1.5x barlow. Having said that i have great results oversampling in the past. But its not great advice. 

Neil

With a 1.5x Barlow, the image would be really small, I attach an image taken on 09.08.22 showing the Ganymede shadow transit using a 2x Barlow, still a bit on the small side, and nothing like as detailed as your images, but much better than I got using the 5x Powermate.

Maybe I should start trying with the 14in Newtonian, a 2x Barlow would give me f10, and a 2.5x Powermate f12.5, but with a focal length of 1800 mm, the image size would be about 80 % bigger than that through the Esprit to start with. 

John 

2 hours ago, neil phillips said:

A early capture from this morning 245 mm Orion Newt

Nice large detailed image, as I mentioned, I get an image around that size using a 5x Powermate with the Esprit 150 and the ZWO 462, but its dim and blurred and I can't improve it that much after stacking and processing in Registax and Lightroom. Nothing like the detail I can see visually looking through the telescope,  clearly I must be doing something wrong.  

John 

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  

17 hours ago, neil phillips said:

I gained some size by doing 1.5x drizzle on registax. I use a fairly large Newtonian because it often will do better than smaller scopes Even a 150 Esprit. Don't underestimate what larger reflectors can do. My Classical cassegrain is supremely sharp. But even that at 7.3" inches cant compete with the bigger Newtonian. To match this you will need a C.9.25 Minimum. 

And the UV IR Cut filters are used as colour balance filters. UV IR wavelengths Will mess up the colour balance of colour images. So the IR UV cut is to prevent that. And you get a natural colour balance. 

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 from 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 (which I couldn't improve much by processing), and have got better results from an old Meade 2x Barlow (may replace it with the 2.5x Powermate), 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 on a massive fork mount made by Rob Miller of Astro 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 

15 minutes ago, neil phillips said:

Hi John here are the stats

 245mm Orion optics UK 1/10TH PV Antares 1/30th pv secondary.  Newtonian F6.3

QHY 462 C camera Baader UV IR Cut Filter Baader Q Barlow. SW EQ5 PRO Mount

Cheers

 

Thanks Neil

I was also amazed how large the image was considering Mars currently only has an 8 arc second disc.

I've taken a few photos of Jupiter and Saturn through my Esprit 150 this week using a ZWO ASI 462 camera (which I assume is similar to the QHY 462) and Sharpcap, but still got a relatively small image size using a 2x Barlow. I tried a Tele Vue 5x Powermate (which I've recently purchased), and although I then got fairly large images, they were very blurred, and I couldn't improve them that much after processing them in Registax and Lightroom.  I'm very much a novice with Sharpcap, so maybe I'm not doing something right.

Is the Baader UV IR Cut Filter similar to the Baader Neodymium (I have one of these), maybe I should try it to see if it improves the view. 

John 

57 minutes ago, neil phillips said:

Taken after I finished Jupiter. Showing Syrtis major and Hellas basin

Amazing photo considering Mars is currently only about 8 arc seconds in diameter, its as good as I got with a 22 arc second disc in October 2020. 

Which scope and camera/barlow combination was it taken with.

John 

I had a nice view of both Saturn and Jupiter early this morning. Cassini's Division on Saturn was the clearest I've seen this year, plus could make out Titan, and a couple of other moons.

In addition I had a nice view of the shadow transit of Ganymede on Jupiter, before I went to bed at around 2 a.m. I only realised when I looked at Astronomy Now Magazine this morning, that had I stopped up another half hour, I would also been able to see the shadow of Io begin to cross the Jovian disc. 

I also attempted some photography with my ZWO ASI 462 Planetary Camera through the Esprit 150 (which usually gives sharper planetary images than the 14in Newtonian) using a 2x Barlow, and stacked and processed in Registax. Not that great (I was able to make out more detail visually), but at least you can make out Cassini's Division, and Ganymede's shadow, plus I think Ganymede and Io to the left of Jupiter.

John 

1 hour ago, PaulM said:

Baader Hyperion Mark 4 8-24mm Zoom Eyepiece with 2.25X Barlow

Interested that you appear to use your Baader Hyperion eyepiece for eyepiece projection photography.

I've purchased the adaptor (43mm to T thread, plus 40mm extension tube) for my 12.5 and 17.5 mm Morpheus eyepieces, but not got round to giving it a try yet, wondered how it compares to using a Barlow or a Powermate, expect that you get greater amplification.

John