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@Thomas Burgess Hi and welcome to SGL too .

I think you are right, but I did not want to confuse matter further

Hopefully we will be able to see at least something before that epoch - but using other means than EM radiation - maybe gravity waves?

If you don't have T2 adapter for your Toucam, then you'll need something like this: https://www.firstlightoptics.com/adapters/baader-125-t2-eyepiece-holder.html That will allow you to connect 1.25" nose piece to T2" connection provided by that Astro Essentials 9x50 adapter to T2 thread. If you have access to 3D printer - you can DIY both adapters as one unit for less money. Some have pointed out that you might have issues when reaching focus with DSLR camera - and I think that is probably true on stock 200p. Mirrorless need less back focus so do your research on getting second hand mirrorless camera - Cannon M100/M200 seem like nice APS-C choices. Not really obligatory - but I'd say common sense at certain budgets. Say you have £500 to spend on camera. You can go for ASI183MC - without cooling, and while you get good QE - you also get amp glow that is best calibrated out by set point temperature camera. You also get 1" sensor. Even if you go second hand - best you can have is 294mc without cooling at that budget. On the other hand - you can easily get APS-C sized sensor for same money. Lesser QE will be offset by sensor size and matching it with larger aperture. You won't have issues with amp glow. Sure, for some budgets - going cooled dedicated camera simply makes more sense - but these tend to be closer to £1000 then to £500 - so for "entry" level - mirrorless / DSLR still seem like best solution - or at least good enough solution.

I've found that it does make a difference both in sharpness and in contrast. Most striking difference that I experienced was actually in night time use - with F/5 refractor. I observed the moon - and apart that green look that I did not particularly like on the moon (for Sun it does not bother me as much) - sharpness and contrast were simply incredible for said scope - razor sharp (not something you expect from F/5 4" refractor).

My point is - neither of the cameras is used optimally as both grossly over sample. ASI290 will create better image - as it can produce more frames, and more frames means better SNR of the stack - which you can sharpen more without bringing the noise out. Properly sampling will give you even better SNR - and you'll be able to sharpen even more.

Ok, here is the same thing done with that image done with ASI290: One of them is original crop - other has been scaled to 1/3 of its size and then enlarged back to match original size - can you tell which is which?

Let me show you something. I've taken crop of one of your images - one that seems sharp enough, and here it is (view this on screen that will display these images without scaling - so not on phone): Then I resized this image down x3 - or down to 33% of original size (equivalent to x3 larger pixel size) And now I'm going to enlarge it back again to 100% as you've captured it: So this last image - is resized small image - enlarged. Can you spot any difference between original and it? If you do that with any image that is properly sampled - difference will be obvious. With over sampling - you simply don't loose anything when you resample down - simply because there is no detail at that resolution. It cannot be due to physics - your telescope simply can't resolve in Ha at that scale.

On solar with quark?

Well yes - for use with Quark - you actually want sensor with large pixels. Only drawback is high read noise of ASI174mm ASI482 seems like really interesting camera to be used with quark - but it is only color for now.

That might be way too much. What scope are you using? If you are using Quark - it has integrated x4.3 telecentric lens. Using scope that is say F/6 with it will result in F/25.8 system. I know that for quark to operate at its best - you need to be at F/25-F/30 - but that is very far from camera best operation. ASI1600 has 3.8µm pixel size and since you are imaging at 656nm - optimum F/ratio is F/11.6 - you might be oversampling by factor of x2 or even x3. Try preprocessing your images with PIPP and selecting 16 bit output (do calibrate with at least darks if not flats as well) and maybe even bin your data to be closer to optimum sampling rate. That will improve your SNR further (which makes it much easier to properly sharpen and there is no need for denoising).

Mount is a good one. Auto-guiding is now main stream and very few people don't guide. Most people also use some sort of computer to control the mount while imaging. This can be laptop, small single board computer like Raspberry PI or even ready made solution like ASIAir that you access/control via phone or tablet. DSLRs are still pretty much in the game because they are affordable, but dedicated / cooled astronomy cameras are now widely adopted. Adoption of CMOS sensors brought prices of dedicated cameras down considerably. Most people astro mod their DSLR at some point (which includes removing stock UV/IR cut filter and replacing it with one suitable for astrophotography). With £500 budget - I'd still consider getting DSLR type camera - or rather camera with exchangeable lens - either DSLR or Mirrorless. Later is more modern and lighter - which can be beneficial for astro imaging. Auto guider setup need not be expensive. You can convert 8x50 finder to guide scope and use that Philips Toucam or any other web camera as guide cam to get you going. If you own laptop - that reduces costs further as you don't need to invest into that. Only thing you further need is suitable cable to connect laptop and mount. Take a look at EQMod software. That is software / drivers - to control SkyWatcher mounts via computer. They have section on making suitable cable yourself (further reducing costs as ready made cables are x2-x3 more expensive than DIY solution - which is pretty simple if you know how to crimp cables). If you get second hand things - I think you'll be able to fit it all into your budget. Second hand DSLR, second hand laptop, and all the bits needed for simple guiding setup - like modified web cam and modified finder.

According to this video - you have about 60 seconds to gather data. https://www.youtube.com/watch?v=u2bXZqASi1c I would actually advise you to experiment a bit and capture longer video. It is easy to split video into chunks if you want to process shorter recordings. AS!3 is capable of aligning features that displace few arc seconds - this means that any motion that happens on such small scales won't actually produce motion blur. Additional benefit is that you can create animations by recording longer video and splitting it into chunks. If you can - try to get large frame rate - like at least 100fps. That way you'll be able to get ~ 20000 frames total for 3-4 minute recording. That is good number of frames for planetary type stacking (you can keep 5-10% and still have significant SNR improvement of over x30).

Try doing some in door testing. There are a few settings that you need to tweak in order to get best FPS performance. I'm using SharpCap so I'll point out settings in that software, but FireCapture should have something similar. If not - give SharpCap a go? - first, be sure to select exposure length that can provide wanted FPS. There is relationship between FPS and exposure length that goes FPS = 1 / exposure in seconds. This really means that you can't achieve more than 5fps if your exposure is 200ms. Since solar is in essence planetary type imaging - you should really restrain your exposure length to 5-6ms regardless of what your histogram or brightness of image say. Go for 10ms in very good seeing. Any exposure longer than that - blurs the image additionally as you won't be freezing the seeing and seeing induced shimmers will add motion blur to the image. - You probably don't need 12bit precision. For that we actually might need to do some math, but if you are sampling at critical sampling rate - you can easily limit yourself to 8bit because short exposure help. In planetary - one often can't even saturate 8bit with needed exposure lengths (I think that signal is about 100e on critical resolution for 5-6ms exposure for Jupiter). - Turn on high speed readout and USB boost: Turbo USB is usually set at 80, but you should set it as high as you can without starting to have issues with image - like black frames (no image) or dropped frames / freezing and such. In the end - get as many frames as possible. Don't limit your run to certain time interval - do research and see what sort of time span you can use before things start to change and get max frames you can in that time frame. To figure out how fast things are changing - look up time laps images of solar activity that have time stamps on and judge by that (or do internet search on the term?). I never looked that up before so I can't be much of a help at the moment, but will look it up later when the time allows and post it here in case you don't manage to find info.

Hi and welcome to SGL.

That happens if you have 16 bit image to begin with. Use 32bit float format for all your steps starting with calibration.

I guess portability? In that price range - GTD E.Fric is probably best option - except it is larger / heavier and can carry 30Kg.

Speed of comet against background depends on where it is currently on its trajectory around the Sun - closer it is - faster it will be going if its path is elliptical. It will also depend on position relative to Earth as Earth is also orbiting around the Sun. You can take for example Stellarium and calculate it's speed in arc seconds per hour or some similar unit and figure out how much it will move in one exposure. For fast moving comets - you can actually guide on comet itself - but then stars will streak. If you decide to image it tonight - well, you are in for a treat - it is crossing M3 tonight - or rather in the morning. Here is info - I plotted two markers at comet position in one hour span and it moves ~6' 23" in that period so it is 6*60" + 23" = 383" per hour or 383" per 3600 seconds. Speed of movement is therefore ~ 0.10639"/s. Now you can calculate how much trailing you'll get in 10s exposure - about 1". Further it depends on your working resolution - how much that will be in pixels. I think you'll be fine with exposures of 10-20 seconds as that will result in ~1px of trailing (provided you are using reasonable sampling rate between 1" and 2" /px). For longer exposures - I'd advise to guide on comet itself.

There are few different types of solar imaging - there is white light solar imaging and then there is narrow band solar imaging - mostly done in Solar H-alpha but there are few other bands that can be used as well. It is better to use planetary type camera like ASI224 than it is to use DSLR as solar is in essence planetary type imaging - which means lucky type imaging. A lot of short exposures, some selected for quality and then stacked and sharpened. If you want to do white light solar with Skymax then you'll need suitable filter and for that type of scope - there is only one suitable type filter and that is front mounted solar filter like this one: https://www.firstlightoptics.com/solar-filters/astrozap-baader-solar-filter.html You can make your own as well - by using this solar film: https://www.firstlightoptics.com/solar-filters/astrosolar-photo-film-od-38.html Do keep in mind that this type of foil comes in two flavors - visual ND5 and photographic - ND3.8. For imaging you want to use latter - ND 3.8 even if you get ready made filter cell. In fact - do pay attention to filter cell. Although you can easily DIY one and save some money - make sure it is not easily removed. If attachment to the scope is flimsy - it can be accidentally knocked off - or maybe gust of wind can remove it. This can lead to serious consequences (much more serious for visual - but even with imaging you can end up with fried equipment). In any case - solar viewing / imaging has some dangers and please be careful and understand risks involved. Even something "benign" like uncovered finder can cause serious damage when pointed to the sun. H-alpha Solar is very expensive. You need either dedicated H-alpha telescope like this one: https://www.firstlightoptics.com/lunt-solar-50mm-h-alpha-telescopes/lunt-ls50tha-h-alpha-solar-telescope.html or specialist filter like this one: https://www.firstlightoptics.com/daystar-quark-solar-eyepieces/daystar-quark-h-alpha-eyepiece-chromosphere-prominence.html or much more expensive version like this: https://www.firstlightoptics.com/daystar-quark-solar-eyepieces/daystar-quantum-se-and-pe-h-alpha-filters.html or maybe this one from Baader: https://www.firstlightoptics.com/solar-filters/baader-sundancer-ii-h-alpha-solar-filter.html In any case - price of such setup is very high.

Well spotted! That is indeed important factor in some cases.

Here is interesting thought that I just had. What if we change the question - just tiny bit? Why do really expensive mounts sell and why are we drawn to them? That question is not nearly as controversial as original one. To me, answer is rather simple and it consist of two things 1. Payload 2. Performance There are few additional minor details - like if you want to guide or not (use of absolute encoders) - and that is it. Not nearly as much mystique or price difference for "last few percent" as with scopes. Interesting isn't it? Maybe this is because performance of the mount is much more easily assessed?

I can't even use binoviewers. My right eye is completely messed up, I have severe astigmatism and see 3 images at once with it . Actually that is self diagnosed - I looked at the Moon and bright stars and I found out that my "PSF" for right eye is something like this: I really see 3 moons superimposed with my right eye when I look at it. That of course makes very blurry image. I think my brain trained itself to ignore image from my right eye for the most part - I can tell that image is even perceived as less bright when using that eye - quick switching between eyes shows distinct less bright / more bright scene.

Hi and welcome to SGL. For £500 you can get life long telescope, and my first instinct is to say this: https://www.firstlightoptics.com/stellalyra-telescopes/stellalyra-8-f6-dobsonian.html I'm just a bit reluctant to do so as it is very large scope. There is old saying that goes - best scope is one used most often. Not much point in having such a large scope if its going to feel like a chore to take it out every night you feel like observing. What sort of scope will suit you best - depends on your habits, your storage space, ability and willingness to carry it outside and setup each time. Some people prefer smaller scope that they can just take and be ready to observe in matter of minutes. These are often referred to as grab&go scopes. Other scopes need longer setup time and often time to cool down to ambient temperature if stored in warm house (optics works the best when at same temperature as ambient air). For that, refractor telescope is best, and something like this should be considered: https://www.firstlightoptics.com/evostar/sky-watcher-evostar-90-660-az-pronto.html This will also save you some money for better accessories - like better diagonal, better eyepieces and so on ...

Don't look at actual chart on screen - that will depend on what size your screen is and how far away you are looking at it If you want to do that sort of test - you need printed chart of certain size and you need well lit room and you need to stand at such distance that 20/20 forms 5' squares. Best done at eye doctor's office

Actually it does - if you have two flies side by side and you want to know if you'll be able to see them as two distinct things - they should be separated by that much arc seconds Where confusion comes from in features that are smaller than Dawes limit and are seen - is about what it means to resolve something. To resolve means - to see as two distinct things - not to see at all. We see stars, and star diameter is waaay smaller than Dawes limit of any one telescope we have ever used. Yet we see them no problem. Similarly - we can see a feature that is rift or gap in ring system even if it's much narrower than Dawes limit. What we can't see is this - if we have two parallel lines and their distance is less than Dawes limit - we won't be able to tell that there are two lines, but we will still see the line. And you are right - MTF is important bit in whole "can you see feature" game. At some point we won't be able to see the line anymore - and that has to do with contrast. If MTF lowers contrast enough - line will blend into background and we won't be able to see it. This effect exists on stars as well - although maybe not directly recognized. Limiting magnitude depends on seeing. On night of poor seeing - we won't be able to go as deep as on night of good seeing. That is because MTF changes because of seeing and it affects contrast of that unresolved star against background.