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@scotty38 What scope are you using here? Can you try something? Shoot your flats in different way with L-eXtreme a bit differently. You need a room that you can make completely dark (if you need laptop / computer in that room - shield it somehow to produce the least light) and place flat panel on the far wall of the room. In essence - shoot normal flats but with flat panel say 3-4 or more meters away from the scope (have scope pointed directly at flat panel and flat panel squared with aperture of course). I suspect that we have some sort of angle dependence at play here. Both ASI294 and L-eXtreme filter have quantum efficiency that depends on angle of incident light. Larger the angle - less light goes thru. If you have fast scope and light is placed right at aperture of scope - it can produce some strange angles on filter and sensor. Ideally - things will even out and we have working flat systems even if flat panels are right next to aperture.

There is OSC model of 2600 too. For some reason, I assumed that you are after mono.

Have a look at ASI2600 mono model. No amp glow, exceptional sensitivity - almost CCD like, but with all nice features of CMOS.

I've found that it is not that significant. Here is one dark calibrated with master dark. Yes, one can see visually that there is a bit more noise in corners (this is ASI178 data - one that has 3 strong star bursts). and actual measurements of stddev in center and bottom right corner give: 8.9 ADU vs 15.4 ADU Not sure what the gain was for this particular recording (I just pulled dark from archive), but this camera has all the gain settings less than 1e/ADU, so actual noise levels in electrons are something like half that - ~4 and ~7. Total of 3e difference I reprocessed the data from this session just a day or two ago (it's snowing so there is not much to do in terms of astronomy) and here is result: This is two hours of 4 minute exposures (30 x 4 minute) in SQM18.5 with 80mm F/4.8 (F/6 with x0.79 FF/FR) and IDAS P2 LPS filter. ASI178mc-cool OSC camera. Neither star burst nor additional noise can be seen in the corners.

If it helps, here is 4 minute -20C dark from my ASI1600: It also displays such features and no real starburst. On the other hand I have "triple" star burst pattern on my ASI178mcc Both cameras calibrate fine.

Like Nik said - actual magnification of barlow lens depends on sensor distance. You can measure it during the day - just insert camera with / without barlow and record some distant feature that you can use to measure pixel scale with - say building or tall pole or whatever. Just measure length of it in pixels in regular and barlowed image and ratio of the two will give you magnification. If you have barlow element that can be screwed off the body - then you can use different extensions to dial in magnification.

Actually no Optimum F/ratio depends on pixel size, and there is simple formula to calculate it: F/ratio = pixel_size * 2 / wavelength (pixel_size and wavelength are in same units - say µm or mm. Wavelength is best used 500nm for color images or exact wavelength for narrowband - say 656 for Ha if you shoot the moon with Ha filter or 850nm if you use IR pass filter). F/ratio = 3.75µm * 2 / 0.5µm = 15 F/15 for ASI224 You actually need x1.5 barlow for C9.25 as it is F/10 scope.

Hi and welcome to SGL. Not really sure what you are asking, but I'll suppose that you are asking if you can use any telescope on non goto mount and answer is yes. As long as you have correct attachment and your mount can handle the weight of telescope - you should be able to put the telescope on the mount and use it like that. Not sure what model of Skywatcher 102 mm do you have (there are several kinds - 102mm F/10 long refractor, 102mm F/5 short refractor, 102mm Maksutov-Cassegrain compact scope) - and what type of EQ mount do you have, but most EQ mounts except few smallest ones (EQ1, EQ2) should be able to carry any of 102mm SW scopes for visual use.

Never seen or heard of dovetail bar that failed, so I'd say that you are ok with cheap version as well as with expensive. As long as it fits your requirements - go for it.

I think that using 230V is not necessary and you'll only loose power in conversion. Laptop usually requires around 18V for charging but is capable of running of 12-14V (not charging). See if you can find device that powers your laptop from car 12V plug and then just use led acid battery to provide you energy?

There is plenty of both signal and noise in that image - you just need to look at it from a distance

I think that is down to automatic stretch rather than anything else. There is no reason why drizzled version would be cleaner as far as noise goes - on the contrary. Here is what you can do to test things. First is - measure values on linear stack. Make sure you register against same reference frame and that any scaling is the same for both stacks so (best to do it without scaling and work with actual ADU values or electron counts) and make selection of same part of background sky and do measurement - look at standard deviation value on same patch. Higher stdev means higher noise. Another thing which is more geared to visual comparison would be - take above linear stacks and simply resize regular stack to match the size of drizzled stack (they will have different sampling rate so you need to up sample regular stack). Then take one half of up sampled regular stack and copy/paste it over drizzled stack - in the same place. Now you have linear "split screen" to compare. What ever stretch you apply will be applied to both images and you'll have direct comparison between the two.

That is quite normal for that sensor and it calibrates out. Even glow and star burst ADU values are not that big to introduce large noise in those places (maybe 2-3e of signal in there).

Yes. Did you use equipment in your signature? Such high FWHM should not really surprise you, and it's not a bad thing. You are shooting wide field with that setup and low sampling rate is ok for such scenario. You have 55mm of aperture and with that aperture alone - airy disk diameter is ~4.7". If you use any sort of field flattener - those usually produce PSF that is not diffraction limited. They fix up corners of the image but overall sharpness suffer. Add to that seeing and mount performance and you can easily get large FWHM even if your focus is spot on - and sometimes a bit of defocus also adds to the problem. As far as I can tell - you have a bit of an issue with tilt in your system? Stars in the right part of the image are a bit astigmatic: That also adds to the issue. Yes, I'd avoid it if at all possible. There are several tutorials out there that promote its use for some reason, and I often hear that people use it because they saw it in being used in tutorial. In most (if not all) cases - there is really no need to use it.

I'm highly skeptical that you are highly undersampled In principle, if you are really undersampled - you can trade some SNR for sharpness by using drizzle, but I think that it never really works in amateur setups. Drizzle was developed for Hubble - which is in outer space and can be pointed precisely. It is used to circumvent undersamplig of telescope PSF. In amateur setups - we have much more variable conditions - each sub has different FWHM and even if we dither, question is can we precisely do partial pixel shifts (we can't really and we rely on randomness). Measure your FWHM to see how much you are undersampled, if any. With 4.51"/px - you need to be below well 7.2" FWHM in order to be under sampled.

RDP should allow for mounting of discs / folders as local disks and then simple file copy. Alternative would be to share folder and then copy via network.

Ah, ok, sorry Yes - it says at x1 - so you were just using device.

What is exactly your setup? Scope -> EP -> PSV-14 Right? Can you put filter onto EP?

I guess that really depends where you place filter? There are several places in optical train that can fit it - and you should choose one that provides best angles (my bet would be before prime focus of telescope).

I'm all for 294 - from performance / price standpoint - it's probably one of the best (together with 2400pro - $4 per mm2).

Quite true. It's like dithering but better

Nice capture, but something about processing just looks "8bit". You know, those old C64 games in low resolution and 16 color palette:

As far as resolution? Sure - measure average FWHM. It should be ~1.6px. If it is larger than that - factor of two values will give you how many "times" you oversampled. Say you measure FWHM of 3.2px then you oversampled by 3.2/1.6 = x2 and you should bin x2 to get proper sampling rate (I just used numbers that give convenient result - but it's never that "easy" - usually you get some "random" value like 2.4px so factor is 2.4/1.6 = 1.5 and there is no easy way to bin x1.5 as binning is integer operation). If you are chasing IFN however - round it up to nearest higher number say you get x3.4 - then bin x4 or if you get x1.5 then bin x2 (or even higher for IFN).

You can just bin linear data that you now have. Mind you - you won't end up with smaller image when viewed on computer or phone screens - unless zoomed in. Posted on SGL for example - it will look the same as image itself is scaled to fit the page. Btw - you are a bit over sampled as is and you need at least bin x2 to get to appropriate resolution. See star sizes and galaxy? That does not look very sharp when viewed at 100% zoom.