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That will be ok. You'll need a computer/laptop with guiding software like PHD2 that will control everything. If you don't want to use laptop in the field, you'll need to look at standalone auto guiding systems. There are a few popular ones - Synguider from SkyWatcher or Lacerta mgen II / III (newer model)

That would be RA direction - what you are seeing is periodic error then. Guiding should solve that. Not sure if star adventurer has periodic error correction? It is one way of dealing with this issue - not perfect but it helps quite a bit sometimes. It basically means "recording" how your mount behaves as it sometimes leads and sometimes trails optimal tracking and then "playing back" those errors "in reverse" - when mount leads, periodic error correction slows it down just enough to balance things out and similarly if mount lags - it speeds it up again to balance tracking out.

Do pay attention that star adventurer only allows for guiding in RA axis. This means that you'll be able to correct issues in RA but not in DEC - which are mostly down to polar alignment error (or wind / cable snag and such). Have you examined your images above for direction? Try to figure out which way is RA and which is DEC in your images (they are perpendicular to each other) and see if trailing coincides with either axis. That will tell you likely cause of trailing (either PA error or periodic error).

Hi and welcome to SGL. Once you move up in focal length, it becomes useful to start thinking in sampling rate rather than focal length. Sampling rate (or sometimes called camera constant and other names) - is amount of sky covered by single pixel. It is expressed in arc seconds per pixel. For example, your camera has 4.5um pixel size, and there is simple formula to calculate sampling rate for your focal length: which gives 1.55"/px for 600mm focal length. 1.55"/px is very serious sampling rate and here everything starts to show - wind, shakes, every glitch of the mount and optical aberrations of your lens. In principle there are two major types of errors in mount that cause trailing - polar alignment error and periodic error. If you have rather good polar alignment - less than 1/5 of a degree out, you will have max drift of about 3.14"/minute. This means that in only one minute, your stars will have 2 pixel trails due to very good polar alignment. On the other hand, periodic error is inherent in the mount due to manufacturing defects (there is no such thing as a perfect circle in engineering) and it can be as high as 30-40" peak to peak. This error repeats every 10 minutes, so there is at least 4"/minute trailing from periodic error - or even more. In any case, if you go with resolution below about 5-6"/px you are really in serious astrophotography waters and you want better mount or at least to start auto guiding.

There are couple of things that I'll need to change here. First is of course - proper wedge. It was by no means easy to get good polar alignment on ball head. Weight is not distributed properly and every time I loosen ball head - it moves a lot under weight. Next thing would be wifi setup. I used AzGti as access point - and wifi is slow that way. I guess it is electronics for wifi in mount is rather rudimentary (simple controller). Next time I'll try with phone being the AP and having everything connect to it instead. Longer exposures are needed - both to try to move signal above noise floor. Calibration is not really proper with DSLR and it is better if signal is stronger and away from noise floor. This will be solved by shutter release cable and intervalometer in synscan app. Of course, best side of this is that it is really portable. Everything is battery powered and can run up to two hours as is - camera is bottle neck at the moment as its battery has smallest capacity. Hopefully I'll be able to move outside of the worst light pollution to do some decent shots next time.

If you don't like it - you don't have to go with very large number of subs. Use gain 100 and long exposure. In the end of your session - shoot just a couple of short exposure (like really short - couple of seconds each). Use these short exposures to fill in saturated parts of the image. Although you have only a few very short exposures - you'll be using them in places where signal is already very strong (saturated sensor in long exposure) - so SNR won't be an issue there. Only "problem" is deciding how to blend short and long data. I prefer to blend in linear stage, but you can blend in stacking phase or later in post processing stage in PS.

I haven't done these so far and I haven't used DSLR in astro imaging so far, thus this image is a lot of firsts for me It did not turn out particularly good, but I'm pleased with it given the circumstances: Color is lacking in Ha regions - SNR was simply too poor to try to get the color out. Star colors should be realistic in this rendition although I did not do any sort of color balance other than basic white balance from camera settings (done manually on the data). This was taken from a red zone - almost whole hour of exposure. Canon 750d unmodded with 55-250 IS STM lens at 55mm F/4 30s ISO1600. 119 stacked subs. FitsWorks for raw to fits conversion and ImageJ for stacking and calibration. Darks, bias, flats ... I'm pretty pleased with star shapes. I'm also rather pleased with AzGTI mount used as star tracker in EQ mode. Over one hour - difference between first and last sub is something like 10px in both RA and DEC. Everything was managed via phone - camera, phone and mount were all connected via wifi and I used canon app to take shots remotely via phone and synscan app to manage the mount (just some basic slewing while framing). I'm planing to add SNAP cable so I can use intervalorimeter on the AzGti mount (or rather app) for longer than 30s exposures. Here are couple of pictures of setup used: I did polar align with use of regular 50x8 finder. This is TS finder shoe that fits nicely in vixen clamp. Btw, I tried processing data with DSS and it made such a mess out of it - almost nothing could be pulled out of that stack.

Why are you trying to compare these two cameras? They don't have same sensor. QHY247C has IMX193 sensor while ASI2600 has IMX571 sensor. QHY has 36K full well and 14bit ADC while ASI one has 50K and 16bit ADC. ASI has rather simple gain scheme - gain is 0.1db units. This means that for 60 gain increase (or closer to 61) - e/ADU value doubles (or rather halves). This makes it easy to calculate any e/ADU value if you know unity gain or any other gain value. In this particular case, since ADC is 16 bit and FW is 50K - there will be no unity gain - initial gain is close to 50K/64K = 50000 / 65535 = ~0.763e/ADU. On the other hand QHY seems to have linear gain - or gain translates into e/ADU linearly (look at first graph - it is line). It starts somewhere around 3.4 at above graph - which is a bit strange since 36K /16K = ~2.13. Initial gain should be somewhere around 2.13e/ADU. There is error with above charts. Indeed, here is chart from QHY website: Other charts can be found here: https://www.qhyccd.com/index.php?m=content&c=index&a=show&catid=94&id=14&cut=1 In any case - you can't just compare gain 0 and gain 100 with doubling exposure and expect it to be the same. Only thing that you get by changing gain is read noise decrease and smaller full well capacity. If you want to compare two gains you need to compare these two values. Let's compare gain 0 and gain 100 for ASI2600 from this perspective: Gain 0 has e/ADU of 0.763e/ADU and gain 100 has e/ADU of about 0.25. Difference in FW will be about 3 times. You need x3 times shorter exposure with gain 100 to match full well capacity when you sum those three exposures. Read noise at 0 gain is about 3.4e while at 100 gain it is about 1.48e (very close to 1.5 but a bit less). When you stack 3 of these smaller read noises - you get 1.48 * sqrt(3) = ~2.5634352e This is less than 3.4e. There fore it is better to use 1/3 exposure with gain 100 than whole exposure at gain 0 - for ASI2600.

Canon has a sort of distinction between number of digits in camera model XXXX - four digit models like 1000, 1100, 2000, etc are "beginner" models - or rather the least feature rich and cheapest. XXX - like 600, 650, 700, 750 is next line - a bit more advanced XX - is already serious line X is professional / large sensor / very expensive This is for EOS DSLR. In spirit, successor for 1000 line might not be XXXX member. How about M100 / M200 mirrorless models as good alternative with price comparison? In fact M200 looks rather interesting as it allows for remote wifi operation. It is light weight, it is APS-C sensor size - rather modern sensor with good specs.

I'm afraid you are out of luck there, but here is alternative: https://www.firstlightoptics.com/misc/zarkov-cloud-gun.html It is a bit expensive, but I'm told its worth every penny.

Even if you could do the full moon in single shot - you don't really want to do that. First thing to note is that while Mak127 might illuminate 28mm diagonal (APS-C) - it will do it with serious vignetting. Rear opening on maksutov scopes is rather small. Here you can see that port is less than 25mm in diameter. Second thing is that every scope is sharpest at the optical axis. As soon as you start moving away from optical axis, you start getting aberrations. There are very few telescopes that are well corrected for large imaging circle. Small aberrations can be tolerated form DSO photography because seeing and tracking blur will mask those, but for planetary imaging - you want your scope to be really sharp. Most people use center of the field for planetary imaging and this is the reason why planetary cameras have small sensors. How do you then create full lunar disk images? By making a mosaic of many panels. Here is an example image taken with Mak102 which has 1300mm FL and camera that has only 8.9mm diagonal (about 1/3 of APS-C by diagonal, about 1/9 by area): This image consists of 9 panels stitched together ... Btw, Mak focal length depends on mirror separation - so each time you refocus - you change effective focal length. Want more focal length - add extenders so that focus position needs to change. Alternative - get Mak102 if you really need to have whole moon in single shot. Better alternative - get small and fast planetary camera and learn to do mosaics. I can only see whole disk image being interesting in Ha solar work as features are so dynamic that doing mosaic would not capture same image. I once did mosaic on solar eclipse with small camera and things did not turn out that well: I did not have time to capture whole sun and cover it with panels and moon moved relative to sun between panels so now looks a bit elongated

If you have your heart set on ASI533 and it suits your budget - then just go for it. Later in use, if you find your images are too blurry when looking at them 1:1 - do super pixel debayering. That will create smaller size image - 1500 x 1500, but things should look better / stars tighter.

Not sure if dynamic range is something that should matter. We take so many subs and increase resulting dynamic range with stacking. Single sub range is not really that important. I also think that dark current is really not that high to be real concern. If we keep it at 0C, that is, according to ZWO ~0.025 e/s/px. If we do reasonable exposure for modern CMOS sensor of about 2 minutes - dark current will be 3e and resulting noise ~1.72e. That is about the size of read noise. If sky glow is swamping read noise at two minutes - it will do the same with dark noise. Impact of dark noise on final image will be very small. Cooling lower will only make things better (although -35C delta T is not that great).

Ok, I'm puzzled by two things here. First - in altitude and azimuth adjustments - RA star motion is at different angle. This should not happen if camera is properly attached to telescope and was not rotated in between alt and az adjustments (and I see no reason to rotate it in the middle of drift alignment). Second, we can't really say what sort of star trailing we have in that last sub. Here is top left corner: This certainly looks like star trailing, but here is upper right corner: hold on, do stars trail diagonally from top left to bottom right direction, or are they trailing vertically an slightly to the right? perhaps they are round and slightly out of focus? This is bottom right corner. bottom left also shows no signs of trailing. It looks like something else is at play here. Btw - your DARV images look really good except for different orientation - and that is puzzling. Is your mount leveled properly?

It looks like quite good camera. I would not mind having one of those either (and no, you don't have to supply one either ) 50% QE is not very good, but it's not bad either. Around 70-75% would be good QE, 80% and above is excellent QE. ASI1600 has QE around 50% mark (maybe close to 60% peak but average is closer to 50% mark) and I have no complaints. It is similar to pixel size, if you compare 50% QE vs for example excellent QE of 85% - first one will need 1.7h or integration time to match SNR of 1h integration time of second higher QE camera - so it's a bit slower, but not by much.

I went thru that thread - but it only gave me headache I've seen above image, but without raw data, there is really nothing I can do to check what is going on. Some say that they are happy with their camera, others have issues. Either there is much sample to sample variations - maybe different drivers or perhaps wrong settings / calibration. It is hard to tell really. What I do know is that I would not mind having a sample of ASI294 and checking it out to see if it works properly

Won't make much difference to FOV - 1000FL in either case. 10" aperture will simply collect more light and will be more demanding on collimation and field correction - both fully illuminated field and fully corrected field.

Have you actually examined set of darks made at different ambient temperature and same set point temperature? What I'm referring to is proper offset value being set. Too low offset will cause clipping in darks and as a consequence - light patches in calibrated lights (in places where darks should have been darker but have been clipped). I personally did not work with said camera but have had PM discussion with one owner and walked them thru proper generation of calibration files and they were rather happy with results.

There are a lot of options out there that will give you what you want. First is to figure out FOV and sampling rate. Since you have 8" scope with 1000mm FL, I would say that your sampling rate should ideally be around 1.2"/px. If you are happy with ASI533 FOV, then let's examine possible candidates, all similarly priced. ASI533 with 3.76um pixels and sampling rate of 0.78"/px. Since this is color camera, your sampling rate is actually double that - 1.55"/px but your pixel sensitivity is like when sampling at 0.78"/px (except that you are sampling 1 red, 1 blue and 2x green images at the same time - confusing, right? ). Use super pixel mode for debayering and you'll get 1500x1500 pixel camera with 1.55"/px sampling rate. Next contender is ASI183 - almost same diagonal so similar FOV It is sampling at 0.5"/px or 1"/px in reality. You can bin it in software to get 2"/px. This will make it be 1374px x 918px equivalent camera, but you'll get rather good collecting surface of 1"/px at 200mm aperture. I would not shy away from ASI294. I think it is quite decent camera from what I've seen - once configured properly. It will sample at 0.96"/px or in reality at 1.91"/px when doing super pixel mode. It will collect as much light per pixel as ASI183 when super pixel debayered and then binned x2 but it will produce images that are 2072px x 1411px. To my mind - that is probably the best option in terms of image size and collecting power and sampling resolution. How about going for ASI183 mono version? You don't have to invest in filters and filter wheel yet if you can be happy with monochromatic images. After all, you said that you are after obscured galaxies (more obscured the better in fact). Those will be low SNR affair and I think you can sacrifice the color in that case for good SNR. With ASI183 mono version, you can "have your cake and eat it too". With bin x3, you'll have 1.49"/px sampling rate and this will translate into full light gathering area for whole spectrum.

My RA was rather stiff but with time I've got the feeling that its becoming better / more fluent - it is almost at the point where one could balance That is probably not the best solution - water is going to shift around and cause shake issues. Smaller bottle filled with sand might be better option - sand is also not the best solution as it is "runny" as well, but at least won't be sloshing around in breeze.

a bit of reverse engineering - finding out focal lengths of mirrors and their separation. Enables you to do calculations of telescope performance in various software and maybe design focal reducer for specific purpose (hint, hint, EEVA - large reduction, corrected field for small sensors?).

Shouldn't focal length of secondary mirror be longer?

No it does not make that assumption. Imagine you have certain sampling rate - and you just simply split each pixel in grid 2x2. Regardless of how many pixels star or nebula initially covered - in this scenario every new pixel will have 1/4 of the photons of original pixel. Smaller pixels - less photons captured. Stars / nebulae - all the same.

Ok, so we have f1 to be negative, f2 to be negative and s to be negative. f1 * f2 is going to be positive, so bottom expression also needs to be positive. Since there is minus sign in front of separation, separation contribution is positive - larger s means larger bottom expression - means less focal length.

It's sort of not obvious to me, so I'll need a little help. if term is (F1 - F2 - x) getting bigger in absolute value as x increases than EFL decreases, but if that term is getting smaller in absolute value as x increases then EFL increases as well. If F1-F2 is negative then absolute value will grow with growing x, and if F1-F2 is positive then it will get smaller with growing x. I would say that sign of F1-F2 determines what happens (if I'm not mistaken).