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Old 31-01-2016, 08:49 PM
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Atmos (Colin)
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What ICX814 camera?

With my mount purchase on hold for the next month or two (awaiting the release of the new ASA DDM60 to get officially specs and price), I figure I may as well get the new camera under way. At the moment I am using a QHY9 with 36mm unmounted filters. As nice as the FOV is, my real gripe with it is the 8.5e- read noise. It is on the lower end of the KAF-8300 sensors so the QHY9 is a good camera. As most of my imaging is happening in light polluted areas (Melbourne) I have mostly been doing narrowband with 3nm filters. With my current setup I need 2 hour subs to hit the noise floor. Without a serious mount upgrade and VERY good polar alignment, I don't see 2 hour subs happening.

My camera list at the moment is:

QHY23 - Easy choice as it means that I can directly attach it onto my current QHY CFW2. QHY have recently released an OAG so I am trying to order one of those.

SX-Trius814 - Company has been around longer, come with OAG and has the ability to tip/tilt the sensor for squareness.

FLI MLx- 814 - Not really on my list because I cannot afford it but with a read noise of 2e- RMS, I want it!

Atik490EX - Although considered the lower end of the market, I don't hear much bad wrap from the Atik range. They also have an integrated OAG which is good.

As nice as the QSI cameras are, I don't have any way of mounting my 36mm filters in one. The one gripe I have against the QHY cameras is their thick heavy power cable, one that neither the Atik or SX cameras use.

From the research I have done, except the FLI, the QHY23 is likely to have the lowest read noise. Although QHY don't seem to have specific specifications on the QHY23, from the few sources I can find on the net, the QHY variants typically have lower read noise. I imagine that both the Atik and Trius are roughly the same at about 4. The FLI slaughters the others but out of my reasonable price range.

I prefer the ICX 814 over the 694 because of the smaller pixels and higher resolution that it brings. Better suit for my typical seeing conditions. Both have very similar QE but the 814 typically has lower read noise which compensates for the smaller pixel size.

So, what do ya'll think?
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Old 01-02-2016, 06:28 AM
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Hi Colin,

I would pick Atik One 9.0 as an integrated kit (with FW and OAG), or, if budget permits, the SX camera, as you could later on add their dedicated Active Optics unit.

ICX 814 from my experience is a very nice sensor, I am sure you will be very happy with any camera you decide to buy from your list.

EDIT: If you are not planning to keep your current camera, then there is an option of selling your current filters or swapping them for smaller ones that would fit a QSI 690 WSG-8, 8 position filter wheel can be quite useful if you would like to add RGB stars/data to your narrowband images

Last edited by Slawomir; 01-02-2016 at 06:52 AM.
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Old 01-02-2016, 11:13 AM
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Hi Colin,

If you want the ICX 814 chip then the QHY24 is the one to go with.
The QHY23 uses the ICX 694 chip.

Physically they are both the same size chip 14.6 x 12.8mm, the 694 chip is 2838 x 2224 with 4.54 micron pixels, the 814 chip is 3468 x 2728 with 3.69 micron pixels.

Well depth may be an issue with the 814, only 15,000e vs 20,000e.

Regards

Bill
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Old 01-02-2016, 04:38 PM
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Originally Posted by Slawomir View Post
Hi Colin,

I would pick Atik One 9.0 as an integrated kit (with FW and OAG), or, if budget permits, the SX camera, as you could later on add their dedicated Active Optics unit.

ICX 814 from my experience is a very nice sensor, I am sure you will be very happy with any camera you decide to buy from your list.

EDIT: If you are not planning to keep your current camera, then there is an option of selling your current filters or swapping them for smaller ones that would fit a QSI 690 WSG-8, 8 position filter wheel can be quite useful if you would like to add RGB stars/data to your narrowband images
The Atik One does look like a nice camera but it doesn't allow for 36mm unmounted filters. I am looking at selling the camera but I would prefer to keep the filters. I could effectively swap the 36mm for a set of brand new 1.25" ones but it does constitute a relatively large monetary drop that is quite unneeded. I currently have set of Astrodon LRGB & Ha OIII SII (all 3nm) so I do want to get a 7x36mm filter wheel, like the one I've already got

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Originally Posted by billdan View Post
Hi Colin,

If you want the ICX 814 chip then the QHY24 is the one to go with.
The QHY23 uses the ICX 694 chip.

Physically they are both the same size chip 14.6 x 12.8mm, the 694 chip is 2838 x 2224 with 4.54 micron pixels, the 814 chip is 3468 x 2728 with 3.69 micron pixels.

Well depth may be an issue with the 814, only 15,000e vs 20,000e.

Regards

Bill
As far as I am aware there is no QHY24. QHY22 is the 694 and QHY23 is the 814, QHY21 is the smaller QHY22 variant. The ICX 694 has a 18,500 e- well depth. Given the smaller pixel size, the ICX814 has 0.66x less surface area which therefore means 0.66x the overall flux per pixel given that they have near identical QE. As the ICX814 only has 0.8x of the well depth, it should take up to ~22% longer for the ICX814 to hit full well depth than the ICX694. Someone can correct me if I am wrong there. Well depth shouldn't be an issue.

From what I can tell the biggest issue is actually going to be in read noise between the two sensors. When comparing the FLI Microline versions, the 814 has 2e- RMS and the 694 has 3e- RMS. This means that even with the smaller pixels (each pixel takes longer to collect the same number of photons), it still reaches read noise limited ~50% quicker than the 694 version due to a lower read noise.
Taking the QHY22 which typically seems to get around 4.5e-. As long as the QHY22 has a read noise 3.65e- or below, it will reach read noise limited as quickly or faster. One of the QHY23 results I have seen is at ~3.3 e-, although there isn't enough of them out there to test whether this is a normal range or unusually low.
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Old 01-02-2016, 05:03 PM
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Oops, that was a blonde moment, must have wrote down it wrong.

Cheers
Bill
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Old 01-02-2016, 05:26 PM
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I will only add to what Colin wrote, that with a low read noise, given all else being equal, you won't need to expose for as long to capture faint bits as opposed to a camera with a high read noise, even with narrowband imaging. Then the sky glow will be your main source of noise and thus limiting factor as for how deep will you be able to go with your imaging or how long you need to expose for. That's why a low read noise camera with 3nm filters allows for taking pretty decent images with relatively short exposures, including in heavily light polluted areas.
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Old 01-02-2016, 05:32 PM
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Quote:
Originally Posted by Atmos View Post
The Atik One does look like a nice camera but it doesn't allow for 36mm unmounted filters. I am looking at selling the camera but I would prefer to keep the filters. I could effectively swap the 36mm for a set of brand new 1.25" ones but it does constitute a relatively large monetary drop that is quite unneeded. I currently have set of Astrodon LRGB & Ha OIII SII (all 3nm) so I do want to get a 7x36mm filter wheel, like the one I've already got
SX has a filter wheel for 7x36mm unmounted filters, and I would pick SX over QHY in no time
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Old 02-02-2016, 10:21 AM
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SX has a filter wheel for 7x36mm unmounted filters, and I would pick SX over QHY in no time
Yep, all the cameras I listed (besides the FLI) have filter wheels for 7x36mm unmounted filters Greg Bradley I believe has a FLI connected to a SX filter wheel so I guess that is always a way to make it work.
I have been thinking about the Adaptive (Active) optics unit that SX have but I have a feeling that it will not fit with my back focus requirements. I'll have to double check, it is either going to JUST make it or be a bit too long. Ideally I want to get a mount that has a smooth enough PE (direct drive or friction drive for instance) that won't be helped by having an AO unit.
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Old 02-02-2016, 05:15 PM
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I thought the adaptive optics was to help with atmospherics not PE
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Old 02-02-2016, 06:20 PM
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I thought the adaptive optics was to help with atmospherics not PE
Professional AO systems that react at thousands of times per second are able to help with seeing. Smaller systems working at ~10x per second (tip/tilt) are largely not able to do anything more than smooth out minor sub second mount errors. I read a report once that did mention that it could help with large convective gas bubbles in the atmosphere as they have a slow moving effect. It would be nice to have a real AO system but I cannot afford the super computer required to do the computations haha
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Old 02-02-2016, 09:29 PM
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Ah cool! Thanks for the info Colin something else for my dream shopping list
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Old 03-02-2016, 10:31 AM
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Quote:
Originally Posted by Atmos View Post
With my mount purchase on hold for the next month or two (awaiting the release of the new ASA DDM60 to get officially specs and price), I figure I may as well get the new camera under way. At the moment I am using a QHY9 with 36mm unmounted filters.
I'll be interested in how you go.

I was considering getting an equivalent to your current setup once I get my observatory up and going (which is close now), but like you I'll have lots of light pollution to deal with. If the lower read noise and better QE of the ICX814 is worth it over the KAF8300, then I'll have to seriously consider that as an option.

Unlike you I don't have the restriction of having a set of expensive filters already, so the Atik One 9.0 looks good, since it takes the smaller 1.25" filters, hence that will save me a bit of cash relative to buying 36mm ones. I want 3nm. Just wish it wasn't only a 5 filter wheel. Hmm
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Old 03-02-2016, 12:43 PM
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Originally Posted by bugeater View Post
I'll be interested in how you go.

I was considering getting an equivalent to your current setup once I get my observatory up and going (which is close now), but like you I'll have lots of light pollution to deal with. If the lower read noise and better QE of the ICX814 is worth it over the KAF8300, then I'll have to seriously consider that as an option.

Unlike you I don't have the restriction of having a set of expensive filters already, so the Atik One 9.0 looks good, since it takes the smaller 1.25" filters, hence that will save me a bit of cash relative to buying 36mm ones. I want 3nm. Just wish it wasn't only a 5 filter wheel. Hmm
If you look into getting a camera with Sony sensor, then I really like QSI WSG-8, as you have all components in one part and then you can bolt a dedicated QSI extension to the camera giving you about 56mm (extra 1mm to account for a filter in the optical path) optimal back focus for most reducers/flatteners. No flex, no misalignment, no worries
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Old 03-02-2016, 01:23 PM
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If you look into getting a camera with Sony sensor, then I really like QSI WSG-8, as you have all components in one part and then you can bolt a dedicated QSI extension to the camera giving you about 56mm (extra 1mm to account for a filter in the optical path) optimal back focus for most reducers/flatteners. No flex, no misalignment, no worries
I like the QSI cameras, particularly the 8 filter wheel, but at near two and a half thousand more than the Atik (which is already stretching the budget)....
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Old 03-02-2016, 01:41 PM
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The difference in read noise between the KAF-8300 and the ICX-814 is not as great as it seems. Scaling by pixel area, 8.5e- for the KAF-8300 is equivalent to about 4e- for the ICX-814.

The ICX-814 does beat the KAF-8300 on QE and dark noise, of course, but the tiny little pixels will only suit a short focal length scope.

Cheers,
Rick.
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Old 03-02-2016, 02:55 PM
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The difference in read noise between the KAF-8300 and the ICX-814 is not as great as it seems. Scaling by pixel area, 8.5e- for the KAF-8300 is equivalent to about 4e- for the ICX-814.

The ICX-814 does beat the KAF-8300 on QE and dark noise, of course, but the tiny little pixels will only suit a short focal length scope.

Cheers,
Rick.
As the read noise gets squared, taking the QE differences in Ha and the pixel size, it equates to the ICX814 being comparable at 6.5e-. So even if the ICX814 were running at 4e- it would still have ~2.6x exposures to be read noise limited. I am working at pretty short focal lengths, not super short.
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Old 03-02-2016, 08:31 PM
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It's me again...

From what I have seen in terms of quality of images (and also financially), it might not be really worth it to swap KAF-8300 for a 50% smaller ICX-814. For narrowband imaging, I would not stick ICX-814 on any scope above 600mm FL, with 400-500mm FL being ideal for this sensor in terms of FOV and image scale (arcseconds per pixel). Maybe it would pay off to wait a bit and see how CMOS sensors evolve over the next year or two I feel that Sony will eventually come up with some very nice CMOS sensors suited for astrophotography, with very low read noise, good QE and a decent size chip.
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Old 03-02-2016, 08:54 PM
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I think the QSI would also be a great choice but with the Aussie dollar being weak it becomes expensive. Although not too much considering the cost of a filter wheel, an OAG and all the adapters to attach them all. And then the possibiiity of tilt and flex.

But if you already have the filter wheel that is a saving.

QSI and FLI are 2 of the best out there. Starlight Express are also very good. I like the all in one design that really started with the SBIG STL series.
Several are now doing it and anyone with experience will know the advantages of a system that gets rid of potential flexure and misalignments. They really cost you sharpness in your images, probably more so than poor seeing.

As far as new Sony sensors I think the low noise Sony Exmor R CMOS sensors are already arriving. I notice there is a planetary cam with something like 1 electron read noise.

CMOS no doubt will be the longer term future but not for a while yet. My Sony A7rii sensor has less than 1 electron read noise at some ISOs. Too bad about the chromatic noise from long exposures!

QHY has a few Sony Exmor CMOS cameras listed on their site. No doubt some future release. Also what appears to be a high end Chinese back illuminated CCD that potentially could be interesting (it would have to prove itself).

As far as scaling pixel size to work out comparable read noise - where did that datum come from?

Sony ICX sensors are way cleaner and more sensitive than the Kodak KAF 8300. Look at the many KAF8300 images around. They are very good but tend to take lots of extra exposure time to arrive at a deeply saturated and clean image. The Sony would take considerable time off needed to achieve that result.

I think your ICX814 would be hard to beat unless you wanted to use it at long focal length but even there you could bin 2x2 and really slam it home.
Small pixels would still have plenty of resolving power at 2x2 with such low read noise.

Greg.
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Old 03-02-2016, 10:23 PM
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It's me again...

From what I have seen in terms of quality of images (and also financially), it might not be really worth it to swap KAF-8300 for a 50% smaller ICX-814. For narrowband imaging, I would not stick ICX-814 on any scope above 600mm FL, with 400-500mm FL being ideal for this sensor in terms of FOV and image scale (arcseconds per pixel). Maybe it would pay off to wait a bit and see how CMOS sensors evolve over the next year or two I feel that Sony will eventually come up with some very nice CMOS sensors suited for astrophotography, with very low read noise, good QE and a decent size chip.
You do make a good point however I guess the biggest issue I will likely end up having when Sony bring out their larger sensors is whether I can afford one! They may be very nice but they'll likely have a large price tag to go with them too

Quote:
Originally Posted by gregbradley View Post
I think the QSI would also be a great choice but with the Aussie dollar being weak it becomes expensive. Although not too much considering the cost of a filter wheel, an OAG and all the adapters to attach them all. And then the possibiiity of tilt and flex.

But if you already have the filter wheel that is a saving.

QSI and FLI are 2 of the best out there. Starlight Express are also very good. I like the all in one design that really started with the SBIG STL series.
Several are now doing it and anyone with experience will know the advantages of a system that gets rid of potential flexure and misalignments. They really cost you sharpness in your images, probably more so than poor seeing.

As far as new Sony sensors I think the low noise Sony Exmor R CMOS sensors are already arriving. I notice there is a planetary cam with something like 1 electron read noise.

CMOS no doubt will be the longer term future but not for a while yet. My Sony A7rii sensor has less than 1 electron read noise at some ISOs. Too bad about the chromatic noise from long exposures!

QHY has a few Sony Exmor CMOS cameras listed on their site. No doubt some future release. Also what appears to be a high end Chinese back illuminated CCD that potentially could be interesting (it would have to prove itself).

As far as scaling pixel size to work out comparable read noise - where did that datum come from?

Sony ICX sensors are way cleaner and more sensitive than the Kodak KAF 8300. Look at the many KAF8300 images around. They are very good but tend to take lots of extra exposure time to arrive at a deeply saturated and clean image. The Sony would take considerable time off needed to achieve that result.

I think your ICX814 would be hard to beat unless you wanted to use it at long focal length but even there you could bin 2x2 and really slam it home.
Small pixels would still have plenty of resolving power at 2x2 with such low read noise.

Greg.
Neither QSI nor FLI have filter wheels that accept 36mm unmounted filters sadly, although the FLI can be mounted onto a SX wheel such as you have done... Somehow.

Some of those cooled CMOS planetary cameras have mindblowingly low read noise. The QHY42 (still in production) is going to have 1.7e- in a 4mp cameras, 11um pixels though which is far too big for my current system.

The scaling of read noise to pixel noise was purely a calculation comparison of flux vs read noise to calculating the exposure time to become read noise limited within a calibrated image.
(3.69^2/5.4^2)*(8.5^2/4^2)*(0.65/0.48)= 2.72
So this is pixel surface area * read noise * QE in Ha which gives the total exposure time difference between two cameras on the same telescope. It doesn't take into consideration the cleanness of the sensor though, the lower dark current, purely read noise limited imaging.

I am going to be imaging at 650mm so with the 3.69um pixels thats working with 1.17"/pixel. It is 1.44"/pixel with the ICX694. This is without using a focal reducer though (still considering it).

Ultimately, money wise, getting the QHY22/23 is the cheapest option for me as I already have a good QHY filter wheel. The only hardware issue I have with QHY is their power cable being big, fat and heavy. Is that a reason to change cameras? In saying that, from the two QHY cameras I have owned (QHY5LII and QHY9), I have never been overly happy with the ASCOM drivers that they have provided and this to me is a big reason for me considering spending that bit more and changing. I'll need to do some research onto how they perform, if they're anything like the two I've already dealt with I'll definitely be swapping companies. Everything works perfectly with their in house software EZCap, this however doesn't allow any form of automation to my understanding though.

I'd love a FLI, I bank account says no QSI would be nice but it does involve a decent investment loss in changing down from a full Astrodon 36mm set to a 1.25" set. The Atik cameras a good and reliable, rarely hear anything bad at all about them in fact. The SX Trius range has been around for a while, more expensive but are they better than the Atik or QHY (software aside) for the price?
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