sorrimen

5 hours ago, Cosmic Geoff said:

Beware the extra path length of several cm. added by the ADC, which may prevent you reaching focus.  

The difficulty of getting a camera to focus in a Newtonian designed for visual use is well known.  One reason for using a SCT or Mak for planetary imaging is that the  focal range is large, making it much easier to accommodate all sorts of imaging accessories.

Something that owners of the ZWO ADC may not have realised is that both the top and bottom sections unscrew, leaving the centre body with a standard thread at each end! 

Yeah I’ve noticed that with the unscrewing. Might be possible to reach focus if I can screw the camera directly into the top. 

9 hours ago, CraigT82 said:

It doesn’t shift the focal point so you will need the ADC’s body length of infocus travel (37mm I think) to be able to use it. I’m surprised you each focus with the barlow so far in as normally the barlow will shift the focal point outwards. On my newts I couldn’t use the ADC without the barlow but I could use it with a barlow as it shifted the focal point out far enough. 
 

As for the extra barlow power you get for putting the ADC in between the barlow and camera, you can work out what this will be using this formula:

Barlow Power = (Barlow FL + Distance) / Barlow FL

With distance being the space between the last lens surface of the barlow and the camera sensor. 

It does actually shift it outwards, as I’m unable to reach focus without it. Rather frustrating as it means I can’t use the ADC by the sounds of things. May be time to invest in a low profile 2” to 1.25” adapter. Thanks for the barlow power info too, will get thinking. 

Hi all

Hope this is in the right section. I’m considering purchasing an ADC for planetary imaging with an 8” dob (as well as just visual use). Currently, with the 2x barlow my asi224 focuses just mm above the focuser bottoming out. Will adding the ADC still allow me to reach focus, or does the focal point remain the same meaning I won’t have enough inwards travel? Of course, it’ll depend on the scope so perhaps a more suitable question is whether it shifts the focal point or not, and in which direction.

Another thing is that I’m currently undersampling (f/12 with a 2x, instead of f/18ish). I was going to purchase a 3x barlow as I’m very comfortable tracking at 2x. With the ADC, I believe it will give me another .5x or so, so would I be better off keeping the 2x, or slightly over sampling with the 3x? Assuming I won’t completely fail at tracking! 

TIA

Ross

1 hour ago, Stu said:

I suspect a field test is the best option, just don’t judge it on one session as you need good transparency to really tell. I assume you’ve got nothing to compare with?

Yeah this is my first use of any filter. Hopefully even the poor examples still provide some contrast benefits.

Okay filter is received. This is very likely a stupid question, but is there any way to tell if it’s a dud other than spectroscopy? I.e. should I be expecting a mirror-like effect when I look through, because it’s more like a blue filter when looking through. 

edit: having said that, even if you could tell I would need to have looked through other filters to distinguish them! Will test it out in the field instead!

I’m Ok_library from reddit. Glad you’ve come here to get some more opinions! I imagine it’s probably just made the decision even harder 🤣  

Important thing that may not seem obvious; are you viewing over buildings? The rising heat will cause any seeing conditions to appear very poor. Ideally you want 360 degrees of flat grass around you, but at least no buildings in the direction you’re observing. 

Another thing is make sure your collimation doesn’t just seem ok. You want to really nail it, even just with a collimation cap. 

Oh to briefly add to the above, there should be an output file type somewhere. This will say something like RAW8, RAW16 or RGB24. You want to select RAW8. 

The output format should also be either .avi or .ser. Note that all of this may be default to you anyway!

Looking good! C9.25 is a fantastic scope to be imaging the solar system with. You’ve clearly been doing some research because most of what you’ve said is right on track. The only thing holding you back is that FPS! I imagine what’s lacking is a combination of exposure and ROI.

The first is easily changed; set your gain to around 80% to start with, and lower your exposure to around 2ms or really just the brightness at which you can see some surface detail to focus on. Checking the histogram is useful for this, but not crucial as anywhere around 50-80% will do just fine.

Make sure your fps is set to ‘Unlimited’ or ‘Uncapped’ or equivalent. Now you’ll want to find ROI or region of interest. Shrink this down until the planet just fits in the box, with a little wiggle room for any tracking errors. Doing this should get you both 1) much higher fps 2) much smaller file sizes for quicker processing  

Great start and good luck moving forward!

Sorry if I’m being obtuse, but what’s stopping you from taking the 10” in the motorhome too? I could understand if you were just in a car or going by public transport but surely an unpowered scope with a dob base is exactly what you’d want for camping? Confused, but maybe I’m misunderstanding! 

When it comes to visual use, aperture really is king and downsizing should be avoided. A good quality frac will outperform a newt of the same aperture, but to get anywhere close to 10” you’re going to be spending a lot. 150mm newt needs a pretty sizeable mount and overall will only save you so much space. Add in powering, polar aligning and balancing the mount and I can’t see a world where this beats a 10” dob for camping. 

Portability certainly has its place and a good frac will definitely be suitable to get into ap plus do some visual, but it’s not going to come close to the 10” dob for the latter and I think with you having a motor home instead of a car I know what I would take with me! 

Of course, if you simply can’t fit the dob in the motorhome then your question is just scope versus no scope, where scope will win! A 150mm newt is going to be a harder  and more pricey start into AP than a small frac, but will be much better visually.

2 hours ago, Stu said:

I’m afraid not! I’m sure there are other places, and it has been a quest for my previous club (Walton Astro Group) to find somewhere which is accessible ie closer than Bignor (which is quite a trek back in the early hours), but still with decent skies.

You may want to catch up with them at some point, @PeterW is involved and a member here.

Sadly that answer was what I expected! Thanks for the heads up, I’ll send Peter a message. In the meantime, going to try and convince my friend that an extra spiral arm is worth doubling our journey for.😁

2 hours ago, Stu said:

Ranmore common is closer and has pretty good skies. The National Trust Denbies car park is a good place, an easy walk through a gate to a field where you can observe.

Oh that’s very close. Would you happen to know any spots in the downs themselves between Bignor and ranmore? It’s only another 10 minutes or so to Haslemere so somewhere in the north of the downs may be ideal (if you think the extra drive from bortle 5 to 4 is worth it). Cheers Stu!

Hi all

Having no car, I’ve been reliant on a friend of mine to drive a couple of us with the scope to somewhere dark. The stars have finally aligned, and the skies tomorrow night in the south downs look clear. Currently I’ve planned Bignor car park, but are there any other good spots you guys know of? Ones closer to London would be ideal as there’s a chance he won’t want to go all the way down to Bignor. TIA

Really enjoying reading this discussion. Once I think I know a lot of what there is to know, an entirely new topic comes up and reminds me that I'm a serious amateur. Loving all this information!

Thanks for the detailed response, Don. I imagine it’s not quite as narrowband as Lumicon or astronomik but better than a much cheaper ‘UHC’? From what I understand also better than the Explore Scientific UHC which fits into the broader-band UHCs?

2” would be ideal, but I’m falling away from buy once cry once for this in particular as I’m settled on eyepieces for now (all 1.25”) and don’t want to wait on a used 2” within budget. 

Hi all

Hope this is the right place for this, but my question is whether the Orion ultrablock narrowband (light pollution filter) is the same as an ultrablock UHC. From what I can gather, they are the same but I’m trying to make sure I’m not purchasing a broadband ‘deep sky/light pollution filter’ rather than a true narrowband UHC. It’s used and in 1.25” format, just in case that has relevance.

TIA

Hi all

A wealth of information and replies here! Still yet to purchase my binoculars, but if a good used pair come up I’ll feel more comfortable having all of this here. And don’t worry, Dave, my first plan is to buy new even after all this help so don’t think it was your comments that put me off! 

Thanks all

Ross

Check out first light optics as they have a summer sale going for zwo asi cameras right now. Michael noted some good options, namely the 224. It’s marginally more expensive than the 120-S with the current sale but is significantly better, and reigned supreme as the best planetary camera for years. I have another post with my untracked results, which can give you an insight into what this camera can do even with the most basic of set ups. DSO imaging is more complicated and you’ll need to plan more carefully around image scale depending on what you want to shoot. 

Note that you may also want to consider image scale for planetary too. Cameras work at an ideal f/ratio depending on their pixel size, and it is 3x-5x the pixel size (seeing dependent). F/ratio dependent, you may find that another camera fits your scope better, depending on whether you will use a barlow or not. A bit of a rabbit hole, but worth looking into if you’re really trying to maximise results. Don’t worry too much unless you’re one to obsess over squeezing every last % of your set up, like I am.

tldr; can’t go wrong with the asi224 right now with the sale. Consider image scale for DSO, and f/ratio for planetary if you are not in a rush. 

1 hour ago, Shimrod said:

It might be worth trying for the planets with what you've got already. Have you seen this thread on imaging the planets with an untracked dob? 

 

I’m the poster of Shimrod’s link here. I would take note of what he said, as with your 12” of aperture versus my 8” you should be able to get some fantastic results. Certainly worth trying untracked before you invest as if you’re questioning whether it’s doable you’ll probably be very pleasantly surprised!

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.

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! 

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! 

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.

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.

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!