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IMX585 with 805mm FL

Equipment CMOS Buying Advice
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Brian avatar
Brian avatar
Hello,

ToupTek currently has a great offer for a mono IMX585, a filter wheel with 1.25" LRGBSHO filters.
I've been wanting to replace my color IMX533 on my 115/805 LZOS for a while now, as I'd like to use a mono camera with this telescope as well.

Does anyone have experience with the small pixels of the IMX585 at a longer focal length like my LZOS, which is around 800mm?
Are the pixels already too small, or does it work well?
An IMX533 mono chip would cost significantly more, especially considering ToupTek's current offer.

I would really appreciate a bit of advice.

Greetings
Brian
Tony Gondola avatar
Tony Gondola avatar
Take a look at the images in my bin, most of then are taken with the color version of the 585. At 900mm I find it perfect and in fact, when the seeing is really good, I find myself wishing the pixels were even a little bit smaller. The ToupTek bundle is an amazing value and will certainly be my next big upgrade.
TiffsAndAstro avatar
TiffsAndAstro avatar
I wonder if they'll offer a 533 mono based version?
Brian avatar
Brian avatar
TiffsAndAstro:
I wonder if they'll offer a 533 mono based version?

Unfortunately, no. I already asked.
There is currently only one offer for the 585 Mono as it has just been introduced.
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Tobiasz avatar
Tobiasz avatar
The ATR585M is an excellent choice for longer focal lenghts because of its HDR mode. You get 0.7-1 electron read noise with around 30k full well. 

The sampling will be brutal, but you swamp the read noise so fast that you can rely on very short exposures (10-30s) which will sharpen up your images quite a bit if the seeing permits. 

The current offer from touptek is a no brainer in my opinion. Perfect entry in the mono business.
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Andreas Zeinert avatar
Andreas Zeinert avatar
Slight oversampling is food for AI deconvolution, don't worry.
Brian Puhl avatar
Brian Puhl avatar
I would argue this isn't a great idea. 

With a 115mm scope, you're already oversampled enough with a 533 at 800mm to be seeing dependent, and likely beyond what the scope will actually resolve.

The smaller pixels means just a bit less light hitting them, on F/7 system.

585 sensor is going to yield a smaller field of view, and likely zero improvement in performance due to the first statement.

Andreas' comment about slight oversampling may be true, but this still relies heavily on seeing conditions.  BlurX is a great tool,  but it becomes easily overdone and obvious when the sharpness just isn't there.


Oversampling has become quite prevalent in this hobby.  Some folks get away with it due to above average seeing conditions.   Most, do not.      Will the 585 work?  Sure!    Is it worth the swap?   Not at all.   I encourage you to evaluate your raw frames and stacks to see what kind of seeing you actually have in your current location.  Measure it from throughout the year.    The 585 is a great camera for wider, undersampled scopes.    I don't think this move in your situation is a good idea.

If money is an objective, I'd suggest switching to a 533 mono.
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andrea tasselli avatar
andrea tasselli avatar
I would totally agree with the above. And beside that, that format is ugly.
Dean Linic avatar
Dean Linic avatar
If ZWO offers that sensor in mono version I would not wait a second, but I don't want to leave AsiAir so I have to wait. I have a ASI 585 MC pro and using it with RedCat 51 and Newtoninan 130 PDS.  Images are more then good so I can imagine mono version. Contrary to some people I like FOV cause I do not need long focal length to shoot galaxies. You are welcome to check my photos all taken with that sensor and I am sure it will help you!!!
Tony Gondola avatar
Tony Gondola avatar
Tobiasz:
The ATR585M is an excellent choice for longer focal lenghts because of its HDR mode. You get 0.7-1 electron read noise with around 30k full well. 

The sampling will be brutal, but you swamp the read noise so fast that you can rely on very short exposures (10-30s) which will sharpen up your images quite a bit if the seeing permits. 

The current offer from touptek is a no brainer in my opinion. Perfect entry in the mono business.

Exactly!
Tony Gondola avatar
Tony Gondola avatar
andrea tasselli:
I would totally agree with the above. And beside that, that format is ugly.

I would contend that the square format, if you don't crop, is pretty limiting from a compositional point of view. A rectangular format forces you to really think about how your image is composed in a way that a square format just doesn't.
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Tony Gondola avatar
Tony Gondola avatar
Brian Puhl:
I would argue this isn't a great idea. 

With a 115mm scope, you're already oversampled enough with a 533 at 800mm to be seeing dependent, and likely beyond what the scope will actually resolve.

The smaller pixels means just a bit less light hitting them, on F/7 system.

585 sensor is going to yield a smaller field of view, and likely zero improvement in performance due to the first statement.

Andreas' comment about slight oversampling may be true, but this still relies heavily on seeing conditions.  BlurX is a great tool,  but it becomes easily overdone and obvious when the sharpness just isn't there.


Oversampling has become quite prevalent in this hobby.  Some folks get away with it due to above average seeing conditions.   Most, do not.      Will the 585 work?  Sure!    Is it worth the swap?   Not at all.   I encourage you to evaluate your raw frames and stacks to see what kind of seeing you actually have in your current location.  Measure it from throughout the year.    The 585 is a great camera for wider, undersampled scopes.    I don't think this move in your situation is a good idea.

If money is an objective, I'd suggest switching to a 533 mono.

I would suggest that sometimes following the hard and fast rules can prevent you from pushing the limits. The other point is that average seeing is just that, average. When I shoot shorter subs and examine the HFD data for the night, it's clear that even an average night can and often does have intervals of great seeing. With proper culling you can exploit that and end up with better resolution than the average seeing would suggest. I really think that the old sampling rules really only apply with log subs. As someone who uses the 585 with a 150mm f/6 I can tell you that by using the above techniques, there are times where I have reached the limit of what I can get out of 2.9 micron pixels and could profit if they were even smaller. That's at 0.66" per pixel.
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Brian Puhl avatar
Brian Puhl avatar
Tony Gondola:
Brian Puhl:
I would argue this isn't a great idea. 

With a 115mm scope, you're already oversampled enough with a 533 at 800mm to be seeing dependent, and likely beyond what the scope will actually resolve.

The smaller pixels means just a bit less light hitting them, on F/7 system.

585 sensor is going to yield a smaller field of view, and likely zero improvement in performance due to the first statement.

Andreas' comment about slight oversampling may be true, but this still relies heavily on seeing conditions.  BlurX is a great tool,  but it becomes easily overdone and obvious when the sharpness just isn't there.


Oversampling has become quite prevalent in this hobby.  Some folks get away with it due to above average seeing conditions.   Most, do not.      Will the 585 work?  Sure!    Is it worth the swap?   Not at all.   I encourage you to evaluate your raw frames and stacks to see what kind of seeing you actually have in your current location.  Measure it from throughout the year.    The 585 is a great camera for wider, undersampled scopes.    I don't think this move in your situation is a good idea.

If money is an objective, I'd suggest switching to a 533 mono.

I would suggest that sometimes following the hard and fast rules can prevent you from pushing the limits. The other point is that average seeing is just that, average. When I shoot shorter subs and examine the HFD data for the night, it's clear that even an average night can and often does have intervals of great seeing. With proper culling you can exploit that and end up with better resolution than the average seeing would suggest. I really think that the old sampling rules really only apply with log subs. As someone who uses the 585 with a 150mm f/6 I can tell you that by using the above techniques, there are times where I have reached the limit of what I can get out of 2.9 micron pixels and could profit if they were even smaller. That's at 0.66" per pixel.



There are valid points against and for this.   I think the key takeaway is 150mm vs 115mm.   Aperture is key, but even then my 150 is still seeing limited 95% of the time, and I run 3.76um pixels. 

Curious, just to have some data to back up your claims, what FWHMs are you able to achieve? With 2.9um and 900mm focal length.
Tony Gondola avatar
Tony Gondola avatar
Brian Puhl:
Tony Gondola:
Brian Puhl:
I would argue this isn't a great idea. 

With a 115mm scope, you're already oversampled enough with a 533 at 800mm to be seeing dependent, and likely beyond what the scope will actually resolve.

The smaller pixels means just a bit less light hitting them, on F/7 system.

585 sensor is going to yield a smaller field of view, and likely zero improvement in performance due to the first statement.

Andreas' comment about slight oversampling may be true, but this still relies heavily on seeing conditions.  BlurX is a great tool,  but it becomes easily overdone and obvious when the sharpness just isn't there.


Oversampling has become quite prevalent in this hobby.  Some folks get away with it due to above average seeing conditions.   Most, do not.      Will the 585 work?  Sure!    Is it worth the swap?   Not at all.   I encourage you to evaluate your raw frames and stacks to see what kind of seeing you actually have in your current location.  Measure it from throughout the year.    The 585 is a great camera for wider, undersampled scopes.    I don't think this move in your situation is a good idea.

If money is an objective, I'd suggest switching to a 533 mono.

I would suggest that sometimes following the hard and fast rules can prevent you from pushing the limits. The other point is that average seeing is just that, average. When I shoot shorter subs and examine the HFD data for the night, it's clear that even an average night can and often does have intervals of great seeing. With proper culling you can exploit that and end up with better resolution than the average seeing would suggest. I really think that the old sampling rules really only apply with log subs. As someone who uses the 585 with a 150mm f/6 I can tell you that by using the above techniques, there are times where I have reached the limit of what I can get out of 2.9 micron pixels and could profit if they were even smaller. That's at 0.66" per pixel.



There are valid points against and for this.   I think the key takeaway is 150mm vs 115mm.   Aperture is key, but even then my 150 is still seeing limited 95% of the time, and I run 3.76um pixels. 

Curious, just to have some data to back up your claims, what FWHMs are you able to achieve? With 2.9um and 900mm focal length.

A good example would be my recent image of M-81 where the average FHWM is 1.0"
Tony Gondola avatar
Tony Gondola avatar
…..opps, FWHM!
CraigT82 avatar
CraigT82 avatar
To throw my 2p in, if you are a BX user, I’d aim correctly sample for the post BX FWHM, rather than the pre BX FWHM.

e.g. recently in my own images I’m sampling at 1.36”pp and that looks ok pre blurx on FWHM stars of approx 3.5”. However after BX the FWHM comes down to 1.7”ish and the stars now look blocky and square. 

If I drizzle my data x2 first then perform the BX the states look perfect.

So of course you don’t have to sample for the smaller FWHM and just use drizzle to resample the data instead

My point is that ‘traditional’ oversampling is not the bad habit it used to be, when we have these AI tools in the shed (for those that embrace them of course)
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JoepsAstronomy avatar
JoepsAstronomy avatar
andrea tasselli:
I would totally agree with the above. And beside that, that format is ugly.

Tony Gondola:
andrea tasselli:
I would totally agree with the above. And beside that, that format is ugly.

I would contend that the square format, if you don't crop, is pretty limiting from a compositional point of view. A rectangular format forces you to really think about how your image is composed in a way that a square format just doesn't.

I have to say rotating the FoV with the 585MC Pro is a bit of a pain. It almost doubles the setup time (checking 10 times if the rotation as you want and adjusting), it means you have to take flats after every object (given that you rotate again for the next object) so having a square sensor is for sure an advantage.

About it being ugly I don't have an opinion. Square just seems easier to use and you can always crop if you want.
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Tony Gondola avatar
Tony Gondola avatar
I don't find manual rotation to be as hard as you describe. I can usually nail the angle to within less than a degree in two or three tries, it's not that hard using NINA. I think composition is important so it's certainly worth the extra effort. On the rest,  I never shoot more than one target a night so the flat thing is a non-issue for my workflow.
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