Adam J

Exactly I would be very dissatisfied if I paid 2k for a tiny CCD sensor and then the ASI2600mm pro came out a few months later and no one had told me about it. It has all the traditional advantages of CCD and CMOS in one package. And as you say of you really want a Sony CCD there are many to be had second hand at great prices.

I find that most people have a fanatical attachment to the sensor / camera that they own. I try to avoid thinking like that. I currently own a ASI1600mm pro but with the new stuff coming out at the moment I would not recommend it to anyone. I would just be telling them to get the very best they can for their cash. In this case January 2021 is not long to wait for a next generation sensor in my opinion. I sold an ATIK 460ex mono that I got as part of a full setup I purchased for another item and bearly got £900 for it a year ago after two months on the board. If he really wants that sensor I would advise he gets a second hand one as there are many coming up on the market for good prices but for a 60% drop from new to used I would not advise buying a new one.

No its not amp glow there isnt really any on a 550D. Looks like vignetting to me, off centre to you have droop or colimation issues, what telescope and filters are you using? The answer is to take flats btw. Adam

Did not realise OP was doing photometry or spectroscopy. That explains everything. But lets face it you can do just fine with a CMOS in that respect too: http://www.astrosurf.com/buil/atik_vs_zwo/ Also we are catigorically not discussing pro observatory equiptment here. Personally I would go with (in comparison to upcoming ASI2600mm or even the 294 for that matter): 1) Higher QE 2) 3x the surface area (larger sensor) 3) Higher dynamic range 4) Faster read times 5) larger full well capacity 6) Less fragile (one cosmic ray hit will not take out an entire column). 7) No dark frames required (IMX571 yes I have a friend who just dithers it) its actually cleaner than the CCD we are talking about here (provably so if you make me) 8 ) No amp glow. So ill ask you for the IMX571 vs ICX694: You say calibration is cleaner, can you prove it? You say dark frames are more consistant, can you prove it? You say CCDs cool better...can you prove it? I strongly suspect that some if not all of what you are saying (while true of older generation CMOS sensors) is no longer true of the latest generation sensors like the IMX571. Sony will cease development of CCD soon, thats a fact and its bacause there are no real advantages to the technology moving forward and they can offer superior sensor in CMOS format. And for the record the performance advantage is so large that even accounting for SW bin 2x2 vs HW bin 2x2 you will still get better SNR from a modern CMOS sensor. No I am talking about an upcoming APS-C that has 26mp and is likely to cost about 2.2k and said "the same technology as the ASI6200mm pro", but you know that dont you? In the last year the price of a new Trius SX694 pro has dropped from a peak of 2.3k to 1.8k. I could be wrong but I would guess its because they are not selling so well. Maybe trying to sell up current sensor stock while its still relevant. Its also possible that the sensor is being sold cheaper by sony...also indicating lower demand. All guesses but I cant think of any other explanations when CMOS cameras are increasing in price at a steady rate taking currency fluctuations into account. Adam

Are you using the correct pattern.

They are both Sony sensors. One is just vastly more capable than the other. The ASI6200mm pro is the same technology and it's talking images on astrobin that a 8 year old CCD can only dream of.

Kinda like some people still have a soft spot of Steam Trains over diesel / electric I guess. I am not aware of any current advantage that the ICX694 would have over a Mono IMX571. Hence I was simply stating my opinion in the hopes of helping the OP. In the end its a fantastic CCD sensor, I just would not buy a new one these days there are superior options for you cash. Second hand, why not. Adam

Well I am not one for observing but as my house was in the way of NEOWISE from my garden observatory I took the 50mm finder off my scope and observed NEOWISE from the front garden with the familiy by attaching it to a camera tripod. Worked perfectly, massively improved the view over nakey eye and had exactly the correct FOV for the target. So that was a 50mm aperture and it was indeed useful. Hence I dont think there is a mimimum useful aperture unless you want to be much more specific about what you are planning to do with it. Adam

Thats walking noise, you really need to dither a CMOS chip, even more so if its OSC. Also i think you are asking too much if you dont expect the darkest area on the image to show some noise above the signal. Adam

So first liht with the scope?

Well to be honest I have seen some very very bad GT81s too so it really is the luck of the draw. Triplet refractors are a mine field hence why I chose my retailer with care. Adam

yes that is horrible 100% unacceptable, what was the outcome for you? Adam

This is my m45 test with my esprit 100 and a ASI1600mm pro, so of course you have issues with micro lens diffraction with the camera. That makes it harder to see the effect you have if it is present at all. Ill let you judge. Adam

kinda, as I understand it the esprit also makes use of silicon plugs to help hold the lens cell, essentially they move the lens elements into position and then silicon them via these plus and then back off the adjustment screws a little. Credit for this image to interferometry blog. So unless you dig out the silicon its never going to be totally free to move. That sort of stuff makes it a very good design in general, certainly better than some other more expensive chinese rebrands. Adam

Dont know how you got that impression FPL-55 is great glass arguably better the FPL-53 because you are more likely to get a well figured lens and yet the despertion is so close to FPL53 that is would make not rea world difference.

You need to upload a full resolution image I feel like that is a down sampled, but perhaps its just the big pixels on the 6D? But from what I see I don't really see the effect I had in this image. My problem showed up in much lower brightness stars, Vega is one of the brightest stars in the sky and although you have some indentation in the halo that is not uncommon on refractors in general and your star really is not that bad. The often those lines are much much darker and more distinct. You would do well to test by pointing at something like m45 as there are is quite a range of star colour and brightness in that target, if you are not seeing something on the seven sisters then this is not something to worry about unless it gets much much worse as temperatures drop. But you cant assume that is going to happen. In terms of the light house beam effect I have seen much worse from an Esprit 100. Above is an example shot from interferometer blog. If you search google for Esprit 100 interferometer blog you will find many examples of what is normal for a Esprit 100. As you see above the halo has dark lines in it just like yours (purple due to baader filter). What I had on mine was very different and resulted in clear spikes / hex shaped stars that when combined in LRGB produced odd chromatic artefacts in the star halo. I also felt that it was not snapping to a fine focus. Bottom line is that I don't see anything immediately concerning in your image. Adam

The effect though undesirable is far from ruining the image in my opinion. This was a 90min test shot i did last year. No Lum just RGB in 30s exposures. No calibration (flats) hence its not too good, but i think the stars are not too bad. Adam

I hear you but the 533 cant come close to producing the image you posted if under bortle 8. Even if it is more capable than previous generation OCS cameras.

Nice but op is in class 8, what about you?

I would love to buy an Atik and get local help / customer service but they need to be offering a wider range of CMOS sensors for that to happen.

In class 8 you should be going mono and focusing on narrow band imaging. The new duel channel filters like L-Extream are great, but in your conditions mono will still be much better. Adam

Probably better signal to noise and I am told that often you don't need to bother with calibration frames (not even darks) if you dither the 533. I know two people with both cameras (533 and 294) and they both agree that it seems easier to get I nicer results out of the 533. I'll try to get them to comment here but they mainly post on Facebook. I have nothing against the 294 really dont but if you don't feel you need the fov for the targets and your setup the 533 is the better sensor. There is also a well known calibration issue with the 294 reported by many on cloudy nights concerning blochie backgrounds that can't be calibrated out. This chap says the same thing. 533 better except for FOV. Discussion of calibration here: https://www.cloudynights.com/topic/636301-asi294mc-calibration-–-testing-notes-thoughts-and-opinions/ But again if you want the FOV it's the 294 or pay for the 2600. Adam

I see better images from the 533 than the 294 people talk about the images being easier to process. That's why I would go for it not because of sampling vlaiv is correct lenses are not likely to be diffraction limited. The only other consideration is FOV and that depends on what you want to image.

Personally if you can afford a new SX694 Pro then I have got to wonder why you would not wait for a mono APS-C CMOS sensor? Or even go with the ASI294mm Pro?

Lots of people are bothered by such things myself included so I would send it back to be adjusted. Don't do it yourself.