Which Camera?


Roland Christen
 

I've been looking long and hard at full frame mono CMOS cameras as a next purchase for our AP observatory. So the question is - which camera - QHY or ZWO?
Which has the better accessories such as filter wheel, off-axis guider etc...
Any and all thoughts welcome.

Rolando


-----Original Message-----
From: Dale Ghent <daleg@...>
To: main@ap-ug.groups.io
Sent: Thu, Jul 1, 2021 12:44 pm
Subject: Re: [ap-ug] Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.



> On Jul 1, 2021, at 01:54, ROBERT WYNNE <robert-wynne@...> wrote:
>
> Based on what I've read on this and other venues I remain unconvinced in CMOS chip technology's ability to capture an equal amount of photons compared to an CCD, in focus and without tilt at the pixel well level with 0 or near 0 noise in reasonable time frames. I would not underestimate my desire to obtain the largest Sony CCD available if the notion caught my interest nor a CMOS chip if the advancement in CMOS quality presents itself in the next year which could easily exceed a 67 mm circle. Thus my push.

With all due respect, but none of this makes any sense.

Current CMOS sensors have QE in the high 80's, pushing 90%, and approach 1e- read noise in typical operating modes. 5, and even 3 minute long narrowband exposures at circa f/5 are normal... no more 15-20 minute exposures that can be ruined by a passing cloud or other interference.  On top of that, you don't need to endure the comparatively glacial readout speeds that CCDs have, which eats into total integration time when you sum up the 15-20 seconds it takes to pull each frame off a CCD camera.

You sentiments would have made more sense perhaps up to 2 years ago. But the current generation of CMOS sensors, namely the IMX533 (1", color), IMX571 (APS-C color+mono), IMX455 (FF, color+mono), and IMX411 (150mp medium format, mono), have performance characteristics that make choosing them over CCD almost a no-brainer. They also have such low dark current that chilling them below -10C is very firmly in the territory of diminishing returns, making these sensors more warm-climate friendly top operate.

I will say that there seems to be a lot of sentimental or emotional attachment to CCDs; perhaps more so now that stocks of them are running on fumes. There are *plenty* of compelling reasons to adopt modern tech, however.





 

Personally i lean towards ZWO

they are very similar (sensor, etc.) but i've had issues with QHY software in the past.

ZWO has it's own software challenges, but they seem to be very active in updating/addressing things. they also have a huge customer base. Customers are also very active helping each other, particularly on facebook (which may be a pro or con depending on how you see it)

I don't think you can go wrong with either, but i would lean towards ZWO

On Thu, Jul 1, 2021 at 1:09 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
I've been looking long and hard at full frame mono CMOS cameras as a next purchase for our AP observatory. So the question is - which camera - QHY or ZWO?
Which has the better accessories such as filter wheel, off-axis guider etc...
Any and all thoughts welcome.

Rolando


-----Original Message-----
From: Dale Ghent <daleg@...>
To: main@ap-ug.groups.io
Sent: Thu, Jul 1, 2021 12:44 pm
Subject: Re: [ap-ug] Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.



> On Jul 1, 2021, at 01:54, ROBERT WYNNE <robert-wynne@...> wrote:
>
> Based on what I've read on this and other venues I remain unconvinced in CMOS chip technology's ability to capture an equal amount of photons compared to an CCD, in focus and without tilt at the pixel well level with 0 or near 0 noise in reasonable time frames. I would not underestimate my desire to obtain the largest Sony CCD available if the notion caught my interest nor a CMOS chip if the advancement in CMOS quality presents itself in the next year which could easily exceed a 67 mm circle. Thus my push.

With all due respect, but none of this makes any sense.

Current CMOS sensors have QE in the high 80's, pushing 90%, and approach 1e- read noise in typical operating modes. 5, and even 3 minute long narrowband exposures at circa f/5 are normal... no more 15-20 minute exposures that can be ruined by a passing cloud or other interference.  On top of that, you don't need to endure the comparatively glacial readout speeds that CCDs have, which eats into total integration time when you sum up the 15-20 seconds it takes to pull each frame off a CCD camera.

You sentiments would have made more sense perhaps up to 2 years ago. But the current generation of CMOS sensors, namely the IMX533 (1", color), IMX571 (APS-C color+mono), IMX455 (FF, color+mono), and IMX411 (150mp medium format, mono), have performance characteristics that make choosing them over CCD almost a no-brainer. They also have such low dark current that chilling them below -10C is very firmly in the territory of diminishing returns, making these sensors more warm-climate friendly top operate.

I will say that there seems to be a lot of sentimental or emotional attachment to CCDs; perhaps more so now that stocks of them are running on fumes. There are *plenty* of compelling reasons to adopt modern tech, however.






--
Brian 



Brian Valente


Eric Weiner
 
Edited

(proof reading is fundamental)

I own several QHY products (none are OSC) and have had zero issues with the hardware or software. I have heard of folks having issues with their software, but I am not one of them.  They are, of course, a Chinese company, and their website and online customer service tools reflect the language barrier.  If, like APCC, one keeps up with the driver updates I think you'll be very satisfied.  
 
In my humble opinion, the build quality of QHY surpasses ZWO' and the QHY desiccant solution is more elegant vs ZWO.  QHY offers several CFWs, each of which can be assembled with various options to accommodate various back focus needs. They even have short focal length versions of the more popular 16-bit cameras.  
 
I have heard getting warranty work completed by QHY can be a chore since one must ship the equipment to China, but rumor says they will soon have repair facilities in the U.S.
 
For what it's worth, Warren Keller of "Insight PixInsight," along with his large group of followers are also QHY fans. 
 
I have heard ATIK makes a good CMOS camera, but their production is behind, and I could not easily achieve my back focus needs with their products.
 
Roland, you're one of the premier scope and mount makers in the world. Contact each company.  I'm sure they'll jump at the chance to offer you their products for "evaluation." 


Roland Christen
 


Roland, you're one of the premier scope and mount makers in the world. Contact each company.  I'm sure they'll jump at the chance to offer you their products for "evaluation." 
Oh, they are in no hurry to provide me with any cameras. I've already asked. Smile
I will buy one same as anyone, from a dealer.

Rolando


-----Original Message-----
From: Eric Weiner <weinere@...>
To: Reply To Group <main@ap-ug.groups.io>
Sent: Thu, Jul 1, 2021 3:32 pm
Subject: Re: [ap-ug] Which Camera?

I am own several QHY products (none are OSC) and have had zero issues with the hardware or software. I have heard of folks having issues with their software, but I am not one of them.  They are, of course, a Chinese company, and their website and online customer service tools reflect the language barrier.  If, like APCC, one keeps up with the driver updates I think you'll be very satisfied.  
 
In my humble opinion, the build quality of QHY surpasses ZWO' and the QHY desiccant solution is more elegant vs ZWO.  QHY offers several CFWs, each of which can be assembled with various options to accommodate various back focus needs. They even have short focal length versions of the more popular 16-bit cameras.  
 
I have heard getting warranty work completed by QHY can be a chore since one must ship the equipment to China, but rumor says they will soon have repair facilities in the U.S.
 
For what it's worth, Warren Keller of "Insight PixInsight," along with his large group of followers are also QHY fans. 
 
I have heard ATIK makes a good CMOS camera, but their production is behind, and I could not easily achieve my back focus needs with their products.
 
Roland, you're one of the premier scope and mount makers in the world. Contact each company.  I'm sure they'll jump at the chance to offer you their products for "evaluation." 


 

>>>I have heard getting warranty work completed by QHY can be a chore since one must ship the equipment to China, but rumor says they will soon have repair facilities in the U.S.

i have heard that for QHY and ZWO. 

Especially with the pandemic, this  seems to have gotten more challenging 

On Thu, Jul 1, 2021 at 1:35 PM Eric Weiner <weinere@...> wrote:

[Edited Message Follows]

(proof reading is fundamental)

I own several QHY products (none are OSC) and have had zero issues with the hardware or software. I have heard of folks having issues with their software, but I am not one of them.  They are, of course, a Chinese company, and their website and online customer service tools reflect the language barrier.  If, like APCC, one keeps up with the driver updates I think you'll be very satisfied.  
 
In my humble opinion, the build quality of QHY surpasses ZWO' and the QHY desiccant solution is more elegant vs ZWO.  QHY offers several CFWs, each of which can be assembled with various options to accommodate various back focus needs. They even have short focal length versions of the more popular 16-bit cameras.  
 
I have heard getting warranty work completed by QHY can be a chore since one must ship the equipment to China, but rumor says they will soon have repair facilities in the U.S.
 
For what it's worth, Warren Keller of "Insight PixInsight," along with his large group of followers are also QHY fans. 
 
I have heard ATIK makes a good CMOS camera, but their production is behind, and I could not easily achieve my back focus needs with their products.
 
Roland, you're one of the premier scope and mount makers in the world. Contact each company.  I'm sure they'll jump at the chance to offer you their products for "evaluation." 



--
Brian 



Brian Valente


Jeffc
 

Fwiw .. I’m a recent QHY268M user.  
I preordered the equivalent ZWO but it was constantly backordered, and QHY became available.  I’m also using the 36mm 7 position filter wheel.   All this is “bolted” together using M54 at the filter wheel end. 

I’ve heard complaints about the software also but I’m using the Ascom driver with SGP / APPM without any problems.  
The only problems  I have run into is related to USB3 cables.   The cable runs have to be short.    I’m also using a Pegasus UPBv2 on the OTA, with a short cable to the Mach2 thru-mount port, and a short cable from the Mach2 to the computer. 

I’m pretty happy with QHY so far. 
As far as adapter availability— I’m standardizing on M54 as much as possible. 

QHY didn’t have a filter drawer (I’d like to add a LPS in the optical path), so I’m going with ZWO for that part.  

ZWO has a usb hub built into the camera, tho I’m not sure that’s beneficial to me. 



On Jul 1, 2021, at 1:36 PM, Brian Valente <bvalente@...> wrote:


>>>I have heard getting warranty work completed by QHY can be a chore since one must ship the equipment to China, but rumor says they will soon have repair facilities in the U.S.

i have heard that for QHY and ZWO. 

Especially with the pandemic, this  seems to have gotten more challenging 

On Thu, Jul 1, 2021 at 1:35 PM Eric Weiner <weinere@...> wrote:

[Edited Message Follows]

(proof reading is fundamental)

I own several QHY products (none are OSC) and have had zero issues with the hardware or software. I have heard of folks having issues with their software, but I am not one of them.  They are, of course, a Chinese company, and their website and online customer service tools reflect the language barrier.  If, like APCC, one keeps up with the driver updates I think you'll be very satisfied.  
 
In my humble opinion, the build quality of QHY surpasses ZWO' and the QHY desiccant solution is more elegant vs ZWO.  QHY offers several CFWs, each of which can be assembled with various options to accommodate various back focus needs. They even have short focal length versions of the more popular 16-bit cameras.  
 
I have heard getting warranty work completed by QHY can be a chore since one must ship the equipment to China, but rumor says they will soon have repair facilities in the U.S.
 
For what it's worth, Warren Keller of "Insight PixInsight," along with his large group of followers are also QHY fans. 
 
I have heard ATIK makes a good CMOS camera, but their production is behind, and I could not easily achieve my back focus needs with their products.
 
Roland, you're one of the premier scope and mount makers in the world. Contact each company.  I'm sure they'll jump at the chance to offer you their products for "evaluation." 



--
Brian 



Brian Valente


Dale Ghent
 

I have the QHY600M (the Pro version, but it's not likely you'll want that), and a bunch of my colleagues have the ZWO ASI6200MM. Both use the IMX455 sensor. I have other ZWO cameras, and have direct experience programming for the software stacks of both companies. We also all sit in a chat together so we always talk about our current camera war stories.

On the whole, QHY and ZWO are equivalent in a broad sense. I prefer some design aspects to the QHY cameras over ZWO's habits, but then I also feel the same about certain ZWO design aspects. QHY have cleaned up their driver situation over the past two years so gripes about that are a bit dated, I feel. This camera functions fine.

The QHY600M comes in 3 main flavors. It's likely you would be getting either the Lite (QHY600L-M) or the Photographic (QHY600PH-M) versions. The obvious difference between the L and PH is price. The L uses the "commercial grade" variant of the IMX455, and the PH model uses the "industrial grade" variant of the same. According to QHY, the differences are chip lifetime, with the industrial variant having some higher MTBF. Accordingly, the QHY600M-L is cheaper.

The PH itself is available in 2 sub-model: the normal one with a 17.5mm backfocus and a "short backfocus" (SBFL) variant that consumes 12.5mm of backfocus. The attachment of the two variants are different. The normal backfocus version attaches to the rear of the QHY filter wheel via circular dovetail that is secured by 3 screws placed around the circumference of the saddle. This saddle is bolted to the rear of the QHY filter wheel. This saddle consumes 6mm of backfocus.

The SBFL variant (12.5mm) of the camera has a different mechanical interface. In addition to the sensor being 5mm closer to the front of the camera, the camera bolts directly onto the rear of the QHY filter wheel. This eliminates the saddle and saves another 6mm of backfocus, bringing the total backfocus savings to 11mm. This SBFL variant is not available on the L model.

In most cases, I would suggest going with the QHY600PH SBFL because of the non-trivial amount of back focal length that's conserved, leaving room for whatever paraphernalia you want between the flattener and filter wheel. It's also better for faster optics because it places the sensor closer to the filters. The "normal" version is useful because that circular dovetail makes rotating the camera quick and simple. If you have a rotator or prefer to rotate the imaging rig via the focuser, then it's obviously not any use in that case.

Outside the mechanical aspects, the QHY600 has 4 readout modes. QHY uses the readout mode facility in a different way than it has been traditionally utilized for on CCDs. These CMOS sensors can be driven in a myriad of different ways which can yield various combinations of pixel well depth, read noise, and dynamic range. QHY details the 4 modes they implement here:

https://www.qhyccd.com/qhy600m-c/#c120

The modes are intended for specific applications, with them being divided more or less along the lines of well depth and noise. The QHY site explains them with graphs. I personally shoot in mode 1 ("High Gain mode") and just inside the High Conversion Gain domain of the sensor.

As for the ZWO analog, it consumes 17.5mm, and I think that can be reduced slightly by removing its front push-pull tilt plate. It does have a 2-port USB2 hub built into the rear, but its intent is mainly for running the filter wheel and an OAG camera. It does not have multiple readout modes, and it drives the sensor in a way that is equivalent most to QHY's mode 1.

There are a bunch of other differences between the two cameras. QHY puts humidity and air pressure sensors in the sensor chamber so you can know when it's time to attach the desiccant tube. Stuff like that.

In the end, you won't go wrong with either choice; the decision comes down to technical specifics, such as needing to conserve backfocus distance or the desire for the different operating modes. If you want, I can throw you some raw frames from my 600.

On Jul 1, 2021, at 16:09, Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:

I've been looking long and hard at full frame mono CMOS cameras as a next purchase for our AP observatory. So the question is - which camera - QHY or ZWO?
Which has the better accessories such as filter wheel, off-axis guider etc...
Any and all thoughts welcome.

Rolando


-----Original Message-----
From: Dale Ghent <daleg@elemental.org>
To: main@ap-ug.groups.io
Sent: Thu, Jul 1, 2021 12:44 pm
Subject: Re: [ap-ug] Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.



On Jul 1, 2021, at 01:54, ROBERT WYNNE <robert-wynne@comcast.net> wrote:

Based on what I've read on this and other venues I remain unconvinced in CMOS chip technology's ability to capture an equal amount of photons compared to an CCD, in focus and without tilt at the pixel well level with 0 or near 0 noise in reasonable time frames. I would not underestimate my desire to obtain the largest Sony CCD available if the notion caught my interest nor a CMOS chip if the advancement in CMOS quality presents itself in the next year which could easily exceed a 67 mm circle. Thus my push.
With all due respect, but none of this makes any sense.

Current CMOS sensors have QE in the high 80's, pushing 90%, and approach 1e- read noise in typical operating modes. 5, and even 3 minute long narrowband exposures at circa f/5 are normal... no more 15-20 minute exposures that can be ruined by a passing cloud or other interference. On top of that, you don't need to endure the comparatively glacial readout speeds that CCDs have, which eats into total integration time when you sum up the 15-20 seconds it takes to pull each frame off a CCD camera.

You sentiments would have made more sense perhaps up to 2 years ago. But the current generation of CMOS sensors, namely the IMX533 (1", color), IMX571 (APS-C color+mono), IMX455 (FF, color+mono), and IMX411 (150mp medium format, mono), have performance characteristics that make choosing them over CCD almost a no-brainer. They also have such low dark current that chilling them below -10C is very firmly in the territory of diminishing returns, making these sensors more warm-climate friendly top operate.

I will say that there seems to be a lot of sentimental or emotional attachment to CCDs; perhaps more so now that stocks of them are running on fumes. There are *plenty* of compelling reasons to adopt modern tech, however.





Dale Ghent
 

On Jul 1, 2021, at 16:50, Jeffc <jeffcrilly@gmail.com> wrote:

QHY didn’t have a filter drawer (I’d like to add a LPS in the optical path), so I’m going with ZWO for that part.
A mono camera with a filter drawer? Are you also using this with a filter wheel?


Roland Christen
 


ZWO has a usb hub built into the camera, tho I’m not sure that’s beneficial to me. 
Would be useful to power a Lodestar off-axis guide camera, which I use.

Roland


-----Original Message-----
From: Jeffc <jeffcrilly@...>
To: main@ap-ug.groups.io
Sent: Thu, Jul 1, 2021 3:50 pm
Subject: Re: [ap-ug] Which Camera?

Fwiw .. I’m a recent QHY268M user.  
I preordered the equivalent ZWO but it was constantly backordered, and QHY became available.  I’m also using the 36mm 7 position filter wheel.   All this is “bolted” together using M54 at the filter wheel end. 

I’ve heard complaints about the software also but I’m using the Ascom driver with SGP / APPM without any problems.  
The only problems  I have run into is related to USB3 cables.   The cable runs have to be short.    I’m also using a Pegasus UPBv2 on the OTA, with a short cable to the Mach2 thru-mount port, and a short cable from the Mach2 to the computer. 

I’m pretty happy with QHY so far. 
As far as adapter availability— I’m standardizing on M54 as much as possible. 

QHY didn’t have a filter drawer (I’d like to add a LPS in the optical path), so I’m going with ZWO for that part.  

ZWO has a usb hub built into the camera, tho I’m not sure that’s beneficial to me. 



On Jul 1, 2021, at 1:36 PM, Brian Valente <bvalente@...> wrote:


>>>I have heard getting warranty work completed by QHY can be a chore since one must ship the equipment to China, but rumor says they will soon have repair facilities in the U.S.

i have heard that for QHY and ZWO. 

Especially with the pandemic, this  seems to have gotten more challenging 

On Thu, Jul 1, 2021 at 1:35 PM Eric Weiner <weinere@...> wrote:
[Edited Message Follows]
(proof reading is fundamental)

I own several QHY products (none are OSC) and have had zero issues with the hardware or software. I have heard of folks having issues with their software, but I am not one of them.  They are, of course, a Chinese company, and their website and online customer service tools reflect the language barrier.  If, like APCC, one keeps up with the driver updates I think you'll be very satisfied.  
 
In my humble opinion, the build quality of QHY surpasses ZWO' and the QHY desiccant solution is more elegant vs ZWO.  QHY offers several CFWs, each of which can be assembled with various options to accommodate various back focus needs. They even have short focal length versions of the more popular 16-bit cameras.  
 
I have heard getting warranty work completed by QHY can be a chore since one must ship the equipment to China, but rumor says they will soon have repair facilities in the U.S.
 
For what it's worth, Warren Keller of "Insight PixInsight," along with his large group of followers are also QHY fans. 
 
I have heard ATIK makes a good CMOS camera, but their production is behind, and I could not easily achieve my back focus needs with their products.
 
Roland, you're one of the premier scope and mount makers in the world. Contact each company.  I'm sure they'll jump at the chance to offer you their products for "evaluation." 


--
Brian 



Brian Valente


Chris White
 

I'm not very satisfied with my ZWO 6200 to be honest.  Sensor tilt is has been a real chore for me to deal with, and thankfully I can fit a Gerd CTU in my image train for precise adjustment, but based on all the reading I have done this is a much bigger problem for ZWO than it is for QHY.   I would have gone with QHY knowing what I know now. 

Atik has announced the APX60 which uses the same sensor IMX455 and I have had conversations with Vince about QC and sensor orthogonality.   They will guarantee precision mounting to 10 microns of precision, which to me is a selling point for such a large sensor and such small pixels.  Estimated availability is september, and I'm seriously considering selling my ZWO to purchase the Atik. 


Bruce Morrell
 

Roland,
Let me know what you want.... Bruce Morrell

On Thu, Jul 1, 2021, 3:09 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
I've been looking long and hard at full frame mono CMOS cameras as a next purchase for our AP observatory. So the question is - which camera - QHY or ZWO?
Which has the better accessories such as filter wheel, off-axis guider etc...
Any and all thoughts welcome.

Rolando


-----Original Message-----
From: Dale Ghent <daleg@...>
To: main@ap-ug.groups.io
Sent: Thu, Jul 1, 2021 12:44 pm
Subject: Re: [ap-ug] Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.



> On Jul 1, 2021, at 01:54, ROBERT WYNNE <robert-wynne@...> wrote:
>
> Based on what I've read on this and other venues I remain unconvinced in CMOS chip technology's ability to capture an equal amount of photons compared to an CCD, in focus and without tilt at the pixel well level with 0 or near 0 noise in reasonable time frames. I would not underestimate my desire to obtain the largest Sony CCD available if the notion caught my interest nor a CMOS chip if the advancement in CMOS quality presents itself in the next year which could easily exceed a 67 mm circle. Thus my push.

With all due respect, but none of this makes any sense.

Current CMOS sensors have QE in the high 80's, pushing 90%, and approach 1e- read noise in typical operating modes. 5, and even 3 minute long narrowband exposures at circa f/5 are normal... no more 15-20 minute exposures that can be ruined by a passing cloud or other interference.  On top of that, you don't need to endure the comparatively glacial readout speeds that CCDs have, which eats into total integration time when you sum up the 15-20 seconds it takes to pull each frame off a CCD camera.

You sentiments would have made more sense perhaps up to 2 years ago. But the current generation of CMOS sensors, namely the IMX533 (1", color), IMX571 (APS-C color+mono), IMX455 (FF, color+mono), and IMX411 (150mp medium format, mono), have performance characteristics that make choosing them over CCD almost a no-brainer. They also have such low dark current that chilling them below -10C is very firmly in the territory of diminishing returns, making these sensors more warm-climate friendly top operate.

I will say that there seems to be a lot of sentimental or emotional attachment to CCDs; perhaps more so now that stocks of them are running on fumes. There are *plenty* of compelling reasons to adopt modern tech, however.





Peter Nagy
 

There is a third alternative camera that uses same Sony IMX-455 sensor (QHY600M and ASI6200MM) and it's made by Atik:

https://www.atik-cameras.com/product/apx60/

It's not yet available for release. I've owned Atik 460EX which uses a soon to be discontinued Sony ICX-694 CCD and it worked great. I believe Atik makes excellent cameras. It will only work with ASCOM camera driver for certain popular capture software like Voyager, SGP, Maxim DL. I believe Nebulosity will work with Atik native drivers.

Personally I have QHY600M-PH camera and it's pretty good. Dale gave an excellent description that I don't think I can add more details. Like Dale said, the driver works fine but can be quirky to set it up but I like it. Unfortunately after one year of use, the USB-3 connector at the rear of the camera broke so I shipped the camera to a repair facility in Santa Barbara (I think it's the same place where SBIG is or used to be) to replace the USB board. QHY will have to build a new USB board in China and ship it to USA for replacement and that can take a while but that's better than shipping my camera back to China.

The back focus (BF) description of 17.5mm for QHY600M-PH is misleading because you have to use the supplied adapter which connects between the camera and the imaging train like filter wheel. If you use QHY CFW3 FW, this adapter adds 4mm BF to the camera's 17.5mm. If you use non-QHY FW or other stuff, this adapter will add minimum of 6mm.

I picked QHY over ZWO for better hardware and ability to use multiple readout modes as Dale describes. Selecting different modes is pretty powerful that allows you to set at the gain you want at lowest possible read noise.

Peter


Peter Nagy
 

For off-axis guider, I recommend Optec Sagitta OAG.

https://www.optecinc.com/astronomy/catalog/oag/

It has a very large 3" (76.2mm) aperture and allows you to adjust the prism stalk height without removing the imaging train and has a very large 12.5mm prism. Most other OAG's prism is 8mm like ZWO and QHY. It comes with manual or motorized guide port focuser. The only drawback is a fairly long BF of 31.75mm or 1.25" but that's most likely because of the larger prism.

For filter wheel, it may be best to use same brand FW as camera but that's not necessary. I've had SX filter wheel and it was very good and reliable with very accurate and repeatable filter slot positioning. SX FW tend to be a bit larger than other brand for same number of filter slots. SX FW are powered by USB.

Peter


Bruce Morrell
 

Here is an interesting article off the Baader website comparing QHY and ZWO cameras.


On Thu, Jul 1, 2021 at 5:05 PM Bruce Morrell via groups.io <bmorrelltx=gmail.com@groups.io> wrote:
Roland,
Let me know what you want.... Bruce Morrell

On Thu, Jul 1, 2021, 3:09 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
I've been looking long and hard at full frame mono CMOS cameras as a next purchase for our AP observatory. So the question is - which camera - QHY or ZWO?
Which has the better accessories such as filter wheel, off-axis guider etc...
Any and all thoughts welcome.

Rolando


-----Original Message-----
From: Dale Ghent <daleg@...>
To: main@ap-ug.groups.io
Sent: Thu, Jul 1, 2021 12:44 pm
Subject: Re: [ap-ug] Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.



> On Jul 1, 2021, at 01:54, ROBERT WYNNE <robert-wynne@...> wrote:
>
> Based on what I've read on this and other venues I remain unconvinced in CMOS chip technology's ability to capture an equal amount of photons compared to an CCD, in focus and without tilt at the pixel well level with 0 or near 0 noise in reasonable time frames. I would not underestimate my desire to obtain the largest Sony CCD available if the notion caught my interest nor a CMOS chip if the advancement in CMOS quality presents itself in the next year which could easily exceed a 67 mm circle. Thus my push.

With all due respect, but none of this makes any sense.

Current CMOS sensors have QE in the high 80's, pushing 90%, and approach 1e- read noise in typical operating modes. 5, and even 3 minute long narrowband exposures at circa f/5 are normal... no more 15-20 minute exposures that can be ruined by a passing cloud or other interference.  On top of that, you don't need to endure the comparatively glacial readout speeds that CCDs have, which eats into total integration time when you sum up the 15-20 seconds it takes to pull each frame off a CCD camera.

You sentiments would have made more sense perhaps up to 2 years ago. But the current generation of CMOS sensors, namely the IMX533 (1", color), IMX571 (APS-C color+mono), IMX455 (FF, color+mono), and IMX411 (150mp medium format, mono), have performance characteristics that make choosing them over CCD almost a no-brainer. They also have such low dark current that chilling them below -10C is very firmly in the territory of diminishing returns, making these sensors more warm-climate friendly top operate.

I will say that there seems to be a lot of sentimental or emotional attachment to CCDs; perhaps more so now that stocks of them are running on fumes. There are *plenty* of compelling reasons to adopt modern tech, however.







ROBERT WYNNE
 

Astrophotographers may want to keep informed on this developing technology a small capacity camera already being vended as of last month. The technology is certainly in its infancy but has the potential to replace all existing technologies within the next 2 years if not sooner. -Best, Robert
 

On 07/01/2021 4:53 PM Bruce Morrell <bmorrelltx@...> wrote:
 
 
Here is an interesting article off the Baader website comparing QHY and ZWO cameras.
 

On Thu, Jul 1, 2021 at 5:05 PM Bruce Morrell via groups.io <bmorrelltx= gmail.com@groups.io> wrote:
Roland,
Let me know what you want.... Bruce Morrell

On Thu, Jul 1, 2021, 3:09 PM Roland Christen via groups.io <chris1011= aol.com@groups.io> wrote:
I've been looking long and hard at full frame mono CMOS cameras as a next purchase for our AP observatory. So the question is - which camera - QHY or ZWO?
Which has the better accessories such as filter wheel, off-axis guider etc...
Any and all thoughts welcome.
 
Rolando
 
 
-----Original Message-----
From: Dale Ghent <daleg@...>
To: main@ap-ug.groups.io
Sent: Thu, Jul 1, 2021 12:44 pm
Subject: Re: [ap-ug] Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.



> On Jul 1, 2021, at 01:54, ROBERT WYNNE < robert-wynne@...> wrote:
>
> Based on what I've read on this and other venues I remain unconvinced in CMOS chip technology's ability to capture an equal amount of photons compared to an CCD, in focus and without tilt at the pixel well level with 0 or near 0 noise in reasonable time frames. I would not underestimate my desire to obtain the largest Sony CCD available if the notion caught my interest nor a CMOS chip if the advancement in CMOS quality presents itself in the next year which could easily exceed a 67 mm circle. Thus my push.

With all due respect, but none of this makes any sense.

Current CMOS sensors have QE in the high 80's, pushing 90%, and approach 1e- read noise in typical operating modes. 5, and even 3 minute long narrowband exposures at circa f/5 are normal... no more 15-20 minute exposures that can be ruined by a passing cloud or other interference.  On top of that, you don't need to endure the comparatively glacial readout speeds that CCDs have, which eats into total integration time when you sum up the 15-20 seconds it takes to pull each frame off a CCD camera.

You sentiments would have made more sense perhaps up to 2 years ago. But the current generation of CMOS sensors, namely the IMX533 (1", color), IMX571 (APS-C color+mono), IMX455 (FF, color+mono), and IMX411 (150mp medium format, mono), have performance characteristics that make choosing them over CCD almost a no-brainer. They also have such low dark current that chilling them below -10C is very firmly in the territory of diminishing returns, making these sensors more warm-climate friendly top operate.

I will say that there seems to be a lot of sentimental or emotional attachment to CCDs; perhaps more so now that stocks of them are running on fumes. There are *plenty* of compelling reasons to adopt modern tech, however.




 

 


 
--


Ram
 
Edited

QHY600 has some annoying quirks

— The OAG they recommend is OAG-M which has an opening smaller than 52mm. The prism will definitely shade incoming rays of light. 

They also sell an OAG-L which unfortunately has no adapters to adapt to the filter wheel CFW3-L. So strangely their CFW3L is not compatible with their OAGL as you would expect but instead is compatible with their OAGM. 

And their OAGM is really too small for the QHY600 chip. 

it’s bad naming and rather poor design. 

A solution to the shading problem is to build a custom adapter from OAG-L to CFW3L. The adapter is non trivial however not  difficult to build  to build properly for various reasons I won’t go into unless someone asks. Precise parts won’t do it as it is a non threaded adapter (too fine threads , too little thread engagement)

Further their drivers are a joke and poorly done. 
install is a real pain. Even after install, there are strange bugs — for instance NINA won’t recognize the camera if camera was connected when NINA was started up. Solution is to unplug or restart camera. Weird.

 

Otherwise I’ve been very happy with the camera. The data is very clean and I don’t sense tilt in my imaging train. I like the way the FW connects to the camera without an inconvenient threaded attachment and uses a dovetail arrangement. 


Peter Nagy
 

That's partly why I recommend Optec Sagitta OAG for reasons I described earlier.

Peter 

— The OAG they recommend is OAG-M which has an opening smaller than 52mm. The prism will definitely shade incoming rays of light. 

They also sell an OAG-L which unfortunately has no adapters to adapt to the filter wheel CFW3-L. So strangely their CFW3L is not compatible with their OAGL as you would expect but instead is compatible with their OAGM. 

And their OAGM is really too small for the QHY600 chip. 

it’s bad naming and rather poor design. 

A solution to the shading problem is to build a custom adapter from OAG-L to CFW3L. The adapter is non trivial however not  difficult to build  to build properly for various reasons I won’t go into unless someone asks. Precise parts won’t do it as it is a non threaded adapter (too fine threads , too little thread engagement)


Bill Long
 

I'm with Chris on this. I got rid of my ASI 6200 due to excessive tilt problems and have no plans to add another imx455 until we get reports from Atik APX60 users. The QHY600 issues Ram noted are why I am passing on that camera as well. If I were in the market I would hold until Atik releases.


From: main@ap-ug.groups.io <main@ap-ug.groups.io> on behalf of Chris White <chris.white@...>
Sent: Thursday, July 1, 2021 2:50 PM
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Subject: Re: [ap-ug] Which Camera?
 
I'm not very satisfied with my ZWO 6200 to be honest.  Sensor tilt is has been a real chore for me to deal with, and thankfully I can fit a Gerd CTU in my image train for precise adjustment, but based on all the reading I have done this is a much bigger problem for ZWO than it is for QHY.   I would have gone with QHY knowing what I know now. 

Atik has announced the APX60 which uses the same sensor IMX455 and I have had conversations with Vince about QC and sensor orthogonality.   They will guarantee precision mounting to 10 microns of precision, which to me is a selling point for such a large sensor and such small pixels.  Estimated availability is september, and I'm seriously considering selling my ZWO to purchase the Atik.