Date   

Re: questions on newly acquired AP130 EDT f/8

albireo1313@...
 

Quick update ... I am selling the case.  It's a bit too tight for the OTA with rings and dovetail bar attached.

As for the dewshield, I talked with AP and they had some EDT decals still available so I bought a few.  George and the AP staff were very helpful an as awesome as always!
Now, off to find a decent body shop to repaint it.

--
Astro-gadfly
New Hampshire
AP Traveler on Gibralter mount


Re: Interesting Back Spacing for 130GTX. Is this far off spec considered normal, and does it even matter?

Chris White
 

Dale,

What spacing did you end up at for the qtcc?


Re: Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.

ROBERT WYNNE
 

Thanks again. Forgot to mention the sensitivity of a jot camera is essentially one photon per equivalent pixel with 0 s/n. -Best, Robert 

On 07/02/2021 1:46 PM Alex M <alex@...> wrote:
 
 
Robert,

My two cents: I would agree with your statement that CCD technology has seen its best days. The amount of money that is spent on CMOS technology annually (My wife works for TSMC and they will likely spend in excess of $30 billion this year on research and new CMOS equipment) dwarfs anything that has ever been spent on CCD technology. None of the current top tier camera companies utilize CCD technology for their main stream personal cameras. All now use CMOS. 

There was another alternative to CMOS and CCD that utilized silicon to filter out RGB data called Fovean. The beauty of this technology was each pixel decodes RGB color dependent upon the varying depth of penetration of the various colors in silicon substrates. In essence, three times the resolution for the same number of pixels. (No Debayer) The company in question never did that well because CMOS was considered lower risk by Sony, Nikon, Canon, etc. The only company to produce a personal SLR camera with the Fovean silicon technology was Sigma. I worked for National Semiconductor for seven years which is the company that funded the initial research into the Fovean silicon solution. 

No turning back at this stage. CMOS will continue to dominate until they hit a physical brick wall that prevents further transistor shrinkage. So far, they keep finding ways around so called limits but the costs to do so grow exponentially.  ($3 plus billion to set up a cutting edge fab line, soon to be 5 billion, etc.)

Best,
Alex





Re: Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.

Alex M
 

Robert,

My two cents: I would agree with your statement that CCD technology has seen its best days. The amount of money that is spent on CMOS technology annually (My wife works for TSMC and they will likely spend in excess of $30 billion this year on research and new CMOS equipment) dwarfs anything that has ever been spent on CCD technology. None of the current top tier camera companies utilize CCD technology for their main stream personal cameras. All now use CMOS. 

There was another alternative to CMOS and CCD that utilized silicon to filter out RGB data called Fovean. The beauty of this technology was each pixel decodes RGB color dependent upon the varying depth of penetration of the various colors in silicon substrates. In essence, three times the resolution for the same number of pixels. (No Debayer) The company in question never did that well because CMOS was considered lower risk by Sony, Nikon, Canon, etc. The only company to produce a personal SLR camera with the Fovean silicon technology was Sigma. I worked for National Semiconductor for seven years which is the company that funded the initial research into the Fovean silicon solution. 

No turning back at this stage. CMOS will continue to dominate until they hit a physical brick wall that prevents further transistor shrinkage. So far, they keep finding ways around so called limits but the costs to do so grow exponentially.  ($3 plus billion to set up a cutting edge fab line, soon to be 5 billion, etc.)

Best,
Alex





Re: Interesting Back Spacing for 130GTX. Is this far off spec considered normal, and does it even matter?

Chris White
 

Dale,

The nice thing about the CTU is precision. One full turn of the screw is 200 microns, so it's easy to work in 8ths turns which is only 25microns a pop!  


Re: Interesting Back Spacing for 130GTX. Is this far off spec considered normal, and does it even matter?

ROBERT WYNNE
 

These micro fine adjustments require a jeweled Swiss dial indicator that reads to .0001" accuracy to gain the exact position one requires, feeler gages and dial calipers have a limit to the degree of accuracy to which they can perform. As to an absolute number for the stack up across the board for the same scope, stacked with different vendor optics; the stack up problems posted on this board distal to the scope seem to be a very individual problem. -Best, Robert

On 07/02/2021 7:21 AM Dale Ghent <daleg@elemental.org> wrote:


I've been following this thread and Chris's journey. I have both the QTCC and 35FF for my 130GTX and received my QHY600 Pro a year ago.

I started out with it hanging on the QTCC, and when I reconfigured my scope for the QHY600 imaging train, I also added in a OAG. After some initial testing, some tilt was evident but what became more apparent was that the back focal distance wasn't working out in practice to what it should have been on paper. I got things to "good enough" out of the interest of moving on and actually enjoying the camera, but reviews of the mechanical distance to what it looked like the problem was (sensor too far from the QTCC) made it seem like I should have been in the right neighborhood, but the results didn't bear that out.

In the fall, I swapped out to the 35FF to see how the IMX455 did on the slower focal ratio and to get some tighter framing for the season's objects. Going from 1.3 arcsec/px to 0.89 was a nice shift in gears. It was also my first time using the 35FF. It did, however, push things to the limit with my junky US east coast skies. This also prompted me to start habitually using pointing models. I also got a Gerd Neumann CTU. Back focal distance and tilt were far more tolerable with the 35FF, and the CTU made in-situ adjustments for tilt a cinch to work out. The process really speeds up once you realize with corner of the sensor corresponds to the physical arrangement.

I switched back to the QTCC last week and, after a night of fiddling, I came to realize that my back focal distance was actually shorter than I had calculated. I had everything spaced out for 81-82mm (Chroma filters, so +1mm there) but it seems like I have /too much/ mechanical distance in there. Well, I couldn't take anything out of my train to shorten it and my QTCC -> M68 adapter from Precise Parts was already at the shortest length they will make them. I realized a solution with the QTCC's own spacer. The 130GTX's spacer is 22.1 mm, but the TEC 140's spacer is 18.3mm. I figured I could swap in the shorter TEC140 spacer and then bump things back out with 1mm spacing rings to get it right.

The hunch worked. I added 3mm of spacing and I am now *very* close. I think I need 0.3-0.5mm more and I'll be golden, and a little tweak to the CTU for tilt. It seems to be that I was indeed 1-2mm over what I should have been. I'm in the midst of a week of crappy weather and I hope that I can work out this last little bit of distance. Here's what CCD-I is telling me. The tilt issue looks large but in reality the adjustment to the CTU to eliminate it is a hair's breadth of an adjustment.

I have calipers and feeler gauges, so I'll measure the distance and the CTU adjustment gap once I get it zeroed in.

https://i.imgur.com/XWVgLo1.png

On Jul 1, 2021, at 19:13, Chris White <chris.white@whitephotogallery.com> wrote:

On Thu, Jul 1, 2021 at 06:03 PM, Roland Christen wrote:
I am testing the color version of this camera on various scopes, and do find one corner off, but I haven't had time to mess with it. The camera is on loan from George, so i don't want to monkey with it.
Have you or are you planning to test with the 130gtx/qtcc? I'll be interested to see how your corner stars look with that sensor. Thank you,



Re: Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.

ROBERT WYNNE
 

Thanks for your advice with which I agree. I'm not making a case for either technology's superiority except for the possibility that one may outpace the other as the technology for each advances. Are all the CCD chip foundry's folding up?
 
The unanswered question I posed is: Has CCD chip technology seen its best days and is now replaced by CMOS permanently? That is where I am uncertain.
 
Then there is the newest JOT technology which has no pixels and promises better S/N and resolution.
 
While we are on the CCD/CMOS topic; there  seems a general consensus that 3.7 micron pixels is the minimum geometry for optimal pixels?
 
Best,
Robert

On 07/02/2021 5:19 AM Edward Beshore via groups.io <ebeshore@...> wrote:
 
 
Robert

Outside of strictly professional applications with unique requirements (for instance, products from companies like e2v), there are few market forces pushing commercial CCD technology to make the technological you hope for.  It’s the  large commercial consumer camera market and the desire for better low light performance (among other things) that have made modern CMOS chips so good, as Dale testifies.

Of course, we amateurs will always be ready for the next great thing, but I think if you peruse astrobin for a while, it will be clear that CMOS is capable of performance levels that exceed most of our skill levels.

Respectfully,

Ed Beshore


Re: ASCOM Connection Problem with Mahc1 GTOCP CP3

George
 

Malik,

 

Please review the appropriate connection method in the following link to be sure that you have it correct.   If there is an issue contact me.  

https://astro-physics.info/tech_support/mounts/quick-start-workflow-guide.pdf

 

Also be sure that you are running all applications as a standard user and not as administrator.

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-222-6538 (direct line)

Phone:  815-282-1513 (office)

Email:  george@...

 

From: main@ap-ug.groups.io <main@ap-ug.groups.io> On Behalf Of Malik AMZIANE
Sent: Friday, July 2, 2021 1:39 PM
To: main@ap-ug.groups.io
Subject: [ap-ug] ASCOM Connection Problem with Mahc1 GTOCP CP3

 

Hello,

 

I have a connection problem with my Mach1 GTO CP3 on a new computer that I have just configured.

I cannot connect two software at the same time to the mount.

Usually it works very well, I connect SGP first, then PHD2 for the guidance in pulse guiding.

But now I can only do one or the other, if one of the two has already been connected, the second responds that there is a connection or port com problem.

 

I am attaching a picture with the error message;

 

On the left in the background, is the first window opened correctly on the SGP connection, on the right a second window which opens when I launch the second connection on PHD.

 

I checked the drivers and installed the same versions as on my other computers, I changed the USB port, but nothing helped.

 

thank you in advance for your help.

 

Malik


ASCOM Connection Problem with Mahc1 GTOCP CP3

Malik AMZIANE
 

Hello,
 
I have a connection problem with my Mach1 GTO CP3 on a new computer that I have just configured.
I cannot connect two software at the same time to the mount.
Usually it works very well, I connect SGP first, then PHD2 for the guidance in pulse guiding.

But now I can only do one or the other, if one of the two has already been connected, the second responds that there is a connection or port com problem.
 
I am attaching a picture with the error message;

 
On the left in the background, is the first window opened correctly on the SGP connection, on the right a second window which opens when I launch the second connection on PHD.
 
I checked the drivers and installed the same versions as on my other computers, I changed the USB port, but nothing helped.
 
thank you in advance for your help.
 
Malik


Re: [ap-gto] Which Camera?

LKDodd <lkdodd@...>
 

Hi

I have a ZWO ASI6200C with ZWO off-axis guider. The off axis guider has some design deficiencies imo. The off axis mirror/guider housing is 1 unit and cannot be locked firmly into the body of the OAG and hence some flexure is possible. Despite tightening the lockscrew as much as I dare you can still move the guide camera sideways relative to the OAG body.

I also have a QHY600M with QHY filter wheel and QHY OAG. Quality of construction is better imo. The OAG is well designed.  The guide camera housing is built into the body of the OAG and the off axis mirror moves as a sub assembly in the body of the OAG.  Also the QHY has a helical focusser built in, where it's an option on the ZWO. Albeit the QHY is more expensive. 

Re camera differences , I like the fact that the power cable has a lock screw on the QHY, also I believe there are internal and chip grade differences in comparative cameras. I have found issues with the USB cables supplied with the QHY, had some strange download issues and had a sequence stopped for no reason on 2 occassions and camera disconnect with NINA. I replaced with aftermarket quality cables and have had no further issues.

I have attached my latest project QHY 600M , Astrodome filters, Tak 105FSQ. Needs more work only curves using masks to date. But you will no doubt be aware of many superb images taken with the QHY600M.

Regards Luke Dodd 



------ Original Message ------
From: "Kenneth Tan" <ktanhs@...>
To: main@ap-gto.groups.io
Cc: "main@ap-ug.groups.io" <main@ap-ug.groups.io>
Sent: Friday, 2 Jul, 2021 At 5:47 PM
Subject: Re: [ap-gto] Which Camera?

I have quite a few zwos . The 6200  is great . I would not get the 2400. The 2600 are ok.
Zwo Filter wheel design acceptable and convenient if you intend to use their system with the asi air pro. But not what i would say the best. A little rough around the edges in implementation. 
OAG best to avoid the zwo

Kenneth


On Fri, 2 Jul 2021 at 04:09, 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@...>
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.





 
--
Roland Christen
Astro-Physics    

     


Re: Interesting Back Spacing for 130GTX. Is this far off spec considered normal, and does it even matter?

Dale Ghent
 

I've been following this thread and Chris's journey. I have both the QTCC and 35FF for my 130GTX and received my QHY600 Pro a year ago.

I started out with it hanging on the QTCC, and when I reconfigured my scope for the QHY600 imaging train, I also added in a OAG. After some initial testing, some tilt was evident but what became more apparent was that the back focal distance wasn't working out in practice to what it should have been on paper. I got things to "good enough" out of the interest of moving on and actually enjoying the camera, but reviews of the mechanical distance to what it looked like the problem was (sensor too far from the QTCC) made it seem like I should have been in the right neighborhood, but the results didn't bear that out.

In the fall, I swapped out to the 35FF to see how the IMX455 did on the slower focal ratio and to get some tighter framing for the season's objects. Going from 1.3 arcsec/px to 0.89 was a nice shift in gears. It was also my first time using the 35FF. It did, however, push things to the limit with my junky US east coast skies. This also prompted me to start habitually using pointing models. I also got a Gerd Neumann CTU. Back focal distance and tilt were far more tolerable with the 35FF, and the CTU made in-situ adjustments for tilt a cinch to work out. The process really speeds up once you realize with corner of the sensor corresponds to the physical arrangement.

I switched back to the QTCC last week and, after a night of fiddling, I came to realize that my back focal distance was actually shorter than I had calculated. I had everything spaced out for 81-82mm (Chroma filters, so +1mm there) but it seems like I have /too much/ mechanical distance in there. Well, I couldn't take anything out of my train to shorten it and my QTCC -> M68 adapter from Precise Parts was already at the shortest length they will make them. I realized a solution with the QTCC's own spacer. The 130GTX's spacer is 22.1 mm, but the TEC 140's spacer is 18.3mm. I figured I could swap in the shorter TEC140 spacer and then bump things back out with 1mm spacing rings to get it right.

The hunch worked. I added 3mm of spacing and I am now *very* close. I think I need 0.3-0.5mm more and I'll be golden, and a little tweak to the CTU for tilt. It seems to be that I was indeed 1-2mm over what I should have been. I'm in the midst of a week of crappy weather and I hope that I can work out this last little bit of distance. Here's what CCD-I is telling me. The tilt issue looks large but in reality the adjustment to the CTU to eliminate it is a hair's breadth of an adjustment.

I have calipers and feeler gauges, so I'll measure the distance and the CTU adjustment gap once I get it zeroed in.

https://i.imgur.com/XWVgLo1.png

On Jul 1, 2021, at 19:13, Chris White <chris.white@whitephotogallery.com> wrote:

On Thu, Jul 1, 2021 at 06:03 PM, Roland Christen wrote:
I am testing the color version of this camera on various scopes, and do find one corner off, but I haven't had time to mess with it. The camera is on loan from George, so i don't want to monkey with it.
Have you or are you planning to test with the 130gtx/qtcc? I'll be interested to see how your corner stars look with that sensor. Thank you,


Re: Which Camera?

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. 


Re: Questoin for Roland: Waited too long to buy 175TCC (discontinued) for my 175EDF....is QUADTCC is as good of a solution.

Edward Beshore
 
Edited

Robert

Outside of strictly professional applications with unique requirements (for instance, products from companies like e2v), there are few market forces pushing commercial CCD technology to make the technological leap you hope for.  It’s the  large commercial consumer camera market and the desire for better low light performance (among other things) that have made modern CMOS chips so good, as Dale testifies.

Of course, we amateurs will always be ready for the next great thing, but I think if you peruse astrobin for a while, it will be clear that CMOS is capable of performance levels that exceed most of our skill levels.

Respectfully,

Ed Beshore


Re: Which Camera?

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)


Re: Interesting Back Spacing for 130GTX. Is this far off spec considered normal, and does it even matter?

Roland Christen
 


Have you or are you planning to test with the 130gtx/qtcc?
I will in the next couple of weeks.

Roland


-----Original Message-----
From: Chris White <chris.white@...>
To: main@ap-ug.groups.io
Sent: Thu, Jul 1, 2021 6:13 pm
Subject: Re: [ap-ug] Interesting Back Spacing for 130GTX. Is this far off spec considered normal, and does it even matter?

On Thu, Jul 1, 2021 at 06:03 PM, Roland Christen wrote:
I am testing the color version of this camera on various scopes, and do find one corner off, but I haven't had time to mess with it. The camera is on loan from George, so i don't want to monkey with it.
Have you or are you planning to test with the 130gtx/qtcc?  I'll be interested to see how your corner stars look with that sensor. Thank you,


Re: Which Camera?

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. 


Re: Which Camera?

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.




 

 


 
--


Re: Which Camera?

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.







Re: Interesting Back Spacing for 130GTX. Is this far off spec considered normal, and does it even matter?

Chris White
 

On Thu, Jul 1, 2021 at 06:03 PM, Roland Christen wrote:
I am testing the color version of this camera on various scopes, and do find one corner off, but I haven't had time to mess with it. The camera is on loan from George, so i don't want to monkey with it.
Have you or are you planning to test with the 130gtx/qtcc?  I'll be interested to see how your corner stars look with that sensor. Thank you,


Re: Which Camera?

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

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