[ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III


Roland Christen
 

I uploaded a full frame test image that I took back in November using a customer's TCC that he claimed had bad star images. This image used the ZWO 6200C color camera. The image has some gradients caused by passing clouds. I shot it on a night of poor transparency, not really interested in getting a pretty pix, just interested in finding out if the TCC was ok or not. The image is pretty much representative of what you would get with a color camera where the RGB frames are all shot at the same focus position.

You would get slightly better star shapes in the blue if you use a monochrome camera and refocus between filters. Although this telecompressor will produce images out to the corners of a full frame camera, it was designed to cover only an APS sized frame. There is vignetting in the full frame image, so you will need to make flats (I used a simple flat shot inside the wall of the observatory).

Tonight I plan to test this compressor on a dark sky with the Moon high above. If I get anything worthwhile, I will post it also. By the way, if you want sharp round stars into the corners, the Field Flattener will achieve that quite nicely. It's still a huge field.

https://www.astrobin.com/j85jln/


-----Original Message-----
From: Eric Weiner <weinere@...>
To: main@ap-ug.groups.io
Sent: Sat, Dec 11, 2021 12:44 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Roland,

I’m still very interested in seeing that FF image using the 92TCC when you have time. 

thanks,
Eric 

--
Roland Christen
Astro-Physics


Roland Christen
 

It's certainly possible to design and build a super sharp telecompressor for the 92 Stowaway to cover the full frame CMOS cameras with sharp round stars into the corners with no vignetting. It would require 3 things, a more exotic compressor design, a larger focuser and market for it. It would be more or less a super astrograph, rather than a small fun portable scope, plus it would cost more. Is the interest there or not, that is the question.

Rolando


-----Original Message-----
From: Roland Christen via groups.io <chris1011@...>
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Sent: Sat, Dec 11, 2021 6:15 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Tonight I'm shooting in very clear skies, very cold sub-freezing, but poor seeing. Moon is also nearby.

Roland

-----Original Message-----
From: Eric Weiner <weinere@...>
To: main@ap-ug.groups.io
Sent: Sat, Dec 11, 2021 6:09 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Thanks Roland. I have the 92FF as well.  Just exploring my options. Focal length of 644 vs 488, a 1’x0.7’ delta. That’s worth the trouble of flats for some targets imho. Our skies in Colorado have been terrible so I haven’t had a chance to experiment with the TCC myself yet. I just got it on Monday. 

Eric






--
Roland Christen
Astro-Physics


Wei-Hao
 

Hi Roland,

There definitely will be interest for such an astrograph.  I am certainly interested.  (Problem is that I can't put my hand on a 92 yet.)  Some of those who plan to buy TAK FSQ will turn their heads to an AP 92 if the reducer has full-frame capability.  Furthermore, I would hope that the flattener can produce a 55mm image circle (sharp corner stars, no or very low vignetting) to cover medium format sensors like the Fuji GFX.

Cheers,
Wei-Hao


Dale Ghent
 

It’s something I would be interested in, and I don’t even have a Stowaway. I have a CFF 92 f/6 refractor and the M63 APM-Riccardi reducer that have been using on it is baaaaarely passable, with some leniency,  when using it with my APS-C sensor. I’m using an OAG with this scope since it’s a compact travel imager, so its pick-off mirror is definitely sitting outside the corrected area in order to avoid intruding into the sensor’s fov. A larger corrected field is certainty something that I miss and would jump at the opportunity to have, even if it meant a focuser upgrade (my CFF 92 came with a 3” FTF; an improved optical design similar to the M63 format or a little larger, would be fine in my case.)

The APS-C Sony IMX571 sensor that is now in many CMOS astrocams is a fantastic sensor and is fairly accessible in terms of price, which is fueling its rise as a common sensor to see now. It’s the smaller cousin of the full-frame IMX455 which is also popular, of course.  A TCC and flattener that could competently handle both would be noticed. Other makes of (mainly Chinese) refractors in the 90-110mm range also lack a competent reducer/flattener for these sensor sizes and one could find use with those. 

On Dec 11, 2021, at 19:33, Roland Christen via groups.io <chris1011@...> wrote:


It's certainly possible to design and build a super sharp telecompressor for the 92 Stowaway to cover the full frame CMOS cameras with sharp round stars into the corners with no vignetting. It would require 3 things, a more exotic compressor design, a larger focuser and market for it. It would be more or less a super astrograph, rather than a small fun portable scope, plus it would cost more. Is the interest there or not, that is the question.

Rolando


-----Original Message-----
From: Roland Christen via groups.io <chris1011@...>
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Sent: Sat, Dec 11, 2021 6:15 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Tonight I'm shooting in very clear skies, very cold sub-freezing, but poor seeing. Moon is also nearby.

Roland

-----Original Message-----
From: Eric Weiner <weinere@...>
To: main@ap-ug.groups.io
Sent: Sat, Dec 11, 2021 6:09 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Thanks Roland. I have the 92FF as well.  Just exploring my options. Focal length of 644 vs 488, a 1’x0.7’ delta. That’s worth the trouble of flats for some targets imho. Our skies in Colorado have been terrible so I haven’t had a chance to experiment with the TCC myself yet. I just got it on Monday. 

Eric






Carl Brosius
 

I would be all over a supercharged 92  Can I get in line now?
Currently using Televue 85 for photography, 11”SCT for visual and AP900 carrying both
Carl

. Fantastical interpretations of my perfect spelling courtesy of Apple. 


On Dec 13, 2021, at 6:13 AM, Dale Ghent <daleg@...> wrote:


It’s something I would be interested in, and I don’t even have a Stowaway. I have a CFF 92 f/6 refractor and the M63 APM-Riccardi reducer that have been using on it is baaaaarely passable, with some leniency,  when using it with my APS-C sensor. I’m using an OAG with this scope since it’s a compact travel imager, so its pick-off mirror is definitely sitting outside the corrected area in order to avoid intruding into the sensor’s fov. A larger corrected field is certainty something that I miss and would jump at the opportunity to have, even if it meant a focuser upgrade (my CFF 92 came with a 3” FTF; an improved optical design similar to the M63 format or a little larger, would be fine in my case.)

The APS-C Sony IMX571 sensor that is now in many CMOS astrocams is a fantastic sensor and is fairly accessible in terms of price, which is fueling its rise as a common sensor to see now. It’s the smaller cousin of the full-frame IMX455 which is also popular, of course.  A TCC and flattener that could competently handle both would be noticed. Other makes of (mainly Chinese) refractors in the 90-110mm range also lack a competent reducer/flattener for these sensor sizes and one could find use with those. 

On Dec 11, 2021, at 19:33, Roland Christen via groups.io <chris1011@...> wrote:


It's certainly possible to design and build a super sharp telecompressor for the 92 Stowaway to cover the full frame CMOS cameras with sharp round stars into the corners with no vignetting. It would require 3 things, a more exotic compressor design, a larger focuser and market for it. It would be more or less a super astrograph, rather than a small fun portable scope, plus it would cost more. Is the interest there or not, that is the question.

Rolando


-----Original Message-----
From: Roland Christen via groups.io <chris1011@...>
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Sent: Sat, Dec 11, 2021 6:15 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Tonight I'm shooting in very clear skies, very cold sub-freezing, but poor seeing. Moon is also nearby.

Roland

-----Original Message-----
From: Eric Weiner <weinere@...>
To: main@ap-ug.groups.io
Sent: Sat, Dec 11, 2021 6:09 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Thanks Roland. I have the 92FF as well.  Just exploring my options. Focal length of 644 vs 488, a 1’x0.7’ delta. That’s worth the trouble of flats for some targets imho. Our skies in Colorado have been terrible so I haven’t had a chance to experiment with the TCC myself yet. I just got it on Monday. 

Eric






Bill Long
 

Well this is good information. The CFF92 was the other scope I thought of for being in the game for a well corrected field. Sounds like it's not terrible with the reducer, but could be improved on. 

What about the flattener? Can it cover the IMX455.

Either way, sounds like more positive data for the AP92 upgrade option for the full frame capability and the TCC.



From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Dale Ghent <daleg@...>
Sent: Monday, December 13, 2021 6:13 AM
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Cc: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III
 
It’s something I would be interested in, and I don’t even have a Stowaway. I have a CFF 92 f/6 refractor and the M63 APM-Riccardi reducer that have been using on it is baaaaarely passable, with some leniency,  when using it with my APS-C sensor. I’m using an OAG with this scope since it’s a compact travel imager, so its pick-off mirror is definitely sitting outside the corrected area in order to avoid intruding into the sensor’s fov. A larger corrected field is certainty something that I miss and would jump at the opportunity to have, even if it meant a focuser upgrade (my CFF 92 came with a 3” FTF; an improved optical design similar to the M63 format or a little larger, would be fine in my case.)

The APS-C Sony IMX571 sensor that is now in many CMOS astrocams is a fantastic sensor and is fairly accessible in terms of price, which is fueling its rise as a common sensor to see now. It’s the smaller cousin of the full-frame IMX455 which is also popular, of course.  A TCC and flattener that could competently handle both would be noticed. Other makes of (mainly Chinese) refractors in the 90-110mm range also lack a competent reducer/flattener for these sensor sizes and one could find use with those. 

On Dec 11, 2021, at 19:33, Roland Christen via groups.io <chris1011@...> wrote:


It's certainly possible to design and build a super sharp telecompressor for the 92 Stowaway to cover the full frame CMOS cameras with sharp round stars into the corners with no vignetting. It would require 3 things, a more exotic compressor design, a larger focuser and market for it. It would be more or less a super astrograph, rather than a small fun portable scope, plus it would cost more. Is the interest there or not, that is the question.

Rolando


-----Original Message-----
From: Roland Christen via groups.io <chris1011@...>
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Sent: Sat, Dec 11, 2021 6:15 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Tonight I'm shooting in very clear skies, very cold sub-freezing, but poor seeing. Moon is also nearby.

Roland

-----Original Message-----
From: Eric Weiner <weinere@...>
To: main@ap-ug.groups.io
Sent: Sat, Dec 11, 2021 6:09 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Thanks Roland. I have the 92FF as well.  Just exploring my options. Focal length of 644 vs 488, a 1’x0.7’ delta. That’s worth the trouble of flats for some targets imho. Our skies in Colorado have been terrible so I haven’t had a chance to experiment with the TCC myself yet. I just got it on Monday. 

Eric






Roland Christen
 


What about the flattener? Can it cover the IMX455.
Yes, the flattener works very well with the IMX455.

Roland


-----Original Message-----
From: Bill Long <bill@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Mon, Dec 13, 2021 2:42 pm
Subject: Re: [ap-gto] [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Well this is good information. The CFF92 was the other scope I thought of for being in the game for a well corrected field. Sounds like it's not terrible with the reducer, but could be improved on. 

What about the flattener? Can it cover the IMX455.

Either way, sounds like more positive data for the AP92 upgrade option for the full frame capability and the TCC.



From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Dale Ghent <daleg@...>
Sent: Monday, December 13, 2021 6:13 AM
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Cc: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III
 
It’s something I would be interested in, and I don’t even have a Stowaway. I have a CFF 92 f/6 refractor and the M63 APM-Riccardi reducer that have been using on it is baaaaarely passable, with some leniency,  when using it with my APS-C sensor. I’m using an OAG with this scope since it’s a compact travel imager, so its pick-off mirror is definitely sitting outside the corrected area in order to avoid intruding into the sensor’s fov. A larger corrected field is certainty something that I miss and would jump at the opportunity to have, even if it meant a focuser upgrade (my CFF 92 came with a 3” FTF; an improved optical design similar to the M63 format or a little larger, would be fine in my case.)

The APS-C Sony IMX571 sensor that is now in many CMOS astrocams is a fantastic sensor and is fairly accessible in terms of price, which is fueling its rise as a common sensor to see now. It’s the smaller cousin of the full-frame IMX455 which is also popular, of course.  A TCC and flattener that could competently handle both would be noticed. Other makes of (mainly Chinese) refractors in the 90-110mm range also lack a competent reducer/flattener for these sensor sizes and one could find use with those. 

On Dec 11, 2021, at 19:33, Roland Christen via groups.io <chris1011@...> wrote:


It's certainly possible to design and build a super sharp telecompressor for the 92 Stowaway to cover the full frame CMOS cameras with sharp round stars into the corners with no vignetting. It would require 3 things, a more exotic compressor design, a larger focuser and market for it. It would be more or less a super astrograph, rather than a small fun portable scope, plus it would cost more. Is the interest there or not, that is the question.

Rolando


-----Original Message-----
From: Roland Christen via groups.io <chris1011@...>
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Sent: Sat, Dec 11, 2021 6:15 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Tonight I'm shooting in very clear skies, very cold sub-freezing, but poor seeing. Moon is also nearby.

Roland

-----Original Message-----
From: Eric Weiner <weinere@...>
To: main@ap-ug.groups.io
Sent: Sat, Dec 11, 2021 6:09 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Thanks Roland. I have the 92FF as well.  Just exploring my options. Focal length of 644 vs 488, a 1’x0.7’ delta. That’s worth the trouble of flats for some targets imho. Our skies in Colorado have been terrible so I haven’t had a chance to experiment with the TCC myself yet. I just got it on Monday. 

Eric






--
Roland Christen
Astro-Physics


Bill Long
 

Sorry, I was asking about the CFF 92 Flattener. 🙂 I know the Stowaway one will. 


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Roland Christen via groups.io <chris1011@...>
Sent: Monday, December 13, 2021 5:59 PM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III
 

What about the flattener? Can it cover the IMX455.
Yes, the flattener works very well with the IMX455.

Roland


-----Original Message-----
From: Bill Long <bill@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Mon, Dec 13, 2021 2:42 pm
Subject: Re: [ap-gto] [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Well this is good information. The CFF92 was the other scope I thought of for being in the game for a well corrected field. Sounds like it's not terrible with the reducer, but could be improved on. 

What about the flattener? Can it cover the IMX455.

Either way, sounds like more positive data for the AP92 upgrade option for the full frame capability and the TCC.



From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Dale Ghent <daleg@...>
Sent: Monday, December 13, 2021 6:13 AM
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Cc: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III
 
It’s something I would be interested in, and I don’t even have a Stowaway. I have a CFF 92 f/6 refractor and the M63 APM-Riccardi reducer that have been using on it is baaaaarely passable, with some leniency,  when using it with my APS-C sensor. I’m using an OAG with this scope since it’s a compact travel imager, so its pick-off mirror is definitely sitting outside the corrected area in order to avoid intruding into the sensor’s fov. A larger corrected field is certainty something that I miss and would jump at the opportunity to have, even if it meant a focuser upgrade (my CFF 92 came with a 3” FTF; an improved optical design similar to the M63 format or a little larger, would be fine in my case.)

The APS-C Sony IMX571 sensor that is now in many CMOS astrocams is a fantastic sensor and is fairly accessible in terms of price, which is fueling its rise as a common sensor to see now. It’s the smaller cousin of the full-frame IMX455 which is also popular, of course.  A TCC and flattener that could competently handle both would be noticed. Other makes of (mainly Chinese) refractors in the 90-110mm range also lack a competent reducer/flattener for these sensor sizes and one could find use with those. 

On Dec 11, 2021, at 19:33, Roland Christen via groups.io <chris1011@...> wrote:


It's certainly possible to design and build a super sharp telecompressor for the 92 Stowaway to cover the full frame CMOS cameras with sharp round stars into the corners with no vignetting. It would require 3 things, a more exotic compressor design, a larger focuser and market for it. It would be more or less a super astrograph, rather than a small fun portable scope, plus it would cost more. Is the interest there or not, that is the question.

Rolando


-----Original Message-----
From: Roland Christen via groups.io <chris1011@...>
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Sent: Sat, Dec 11, 2021 6:15 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Tonight I'm shooting in very clear skies, very cold sub-freezing, but poor seeing. Moon is also nearby.

Roland

-----Original Message-----
From: Eric Weiner <weinere@...>
To: main@ap-ug.groups.io
Sent: Sat, Dec 11, 2021 6:09 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Thanks Roland. I have the 92FF as well.  Just exploring my options. Focal length of 644 vs 488, a 1’x0.7’ delta. That’s worth the trouble of flats for some targets imho. Our skies in Colorado have been terrible so I haven’t had a chance to experiment with the TCC myself yet. I just got it on Monday. 

Eric






--
Roland Christen
Astro-Physics


Dale Ghent
 

I never did get the CFF flattener because it wasn't available when I received the CFF92, and I wanted to try to find a reducer+flattener system that had the same (or very close to the same) BFL so they could be interchangeable using the same Precise Parts adapter, with only a few shims of difference between them. But that didn't happen and all I've been using is the M63 reducer. That was perfectly fine with the 4/3 sensor in the ASI1600 I was using on it. The QHY268 pushes it just enough more that it's flaking out rapidly at the corners, as f/4.5 light cones are good at doing. I'm sure APS-C would be fine corner-to-corner on the slower f/6.9 version of the CFF92 with this reducer.

A "unicorn" solution, for me at least, would be this super reducer that can be stuffed into the rear of a 3" FTF or Nitecrawler, with a paired flattener that has the same BFL to keep framing options open without much ado when it comes to adapter configuration.

On Dec 13, 2021, at 15:42, Bill Long <bill@...> wrote:

Well this is good information. The CFF92 was the other scope I thought of for being in the game for a well corrected field. Sounds like it's not terrible with the reducer, but could be improved on.

What about the flattener? Can it cover the IMX455.

Either way, sounds like more positive data for the AP92 upgrade option for the full frame capability and the TCC.


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Dale Ghent <daleg@...>
Sent: Monday, December 13, 2021 6:13 AM
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Cc: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

It’s something I would be interested in, and I don’t even have a Stowaway. I have a CFF 92 f/6 refractor and the M63 APM-Riccardi reducer that have been using on it is baaaaarely passable, with some leniency, when using it with my APS-C sensor. I’m using an OAG with this scope since it’s a compact travel imager, so its pick-off mirror is definitely sitting outside the corrected area in order to avoid intruding into the sensor’s fov. A larger corrected field is certainty something that I miss and would jump at the opportunity to have, even if it meant a focuser upgrade (my CFF 92 came with a 3” FTF; an improved optical design similar to the M63 format or a little larger, would be fine in my case.)

The APS-C Sony IMX571 sensor that is now in many CMOS astrocams is a fantastic sensor and is fairly accessible in terms of price, which is fueling its rise as a common sensor to see now. It’s the smaller cousin of the full-frame IMX455 which is also popular, of course. A TCC and flattener that could competently handle both would be noticed. Other makes of (mainly Chinese) refractors in the 90-110mm range also lack a competent reducer/flattener for these sensor sizes and one could find use with those.

On Dec 11, 2021, at 19:33, Roland Christen via groups.io <chris1011@...> wrote:


It's certainly possible to design and build a super sharp telecompressor for the 92 Stowaway to cover the full frame CMOS cameras with sharp round stars into the corners with no vignetting. It would require 3 things, a more exotic compressor design, a larger focuser and market for it. It would be more or less a super astrograph, rather than a small fun portable scope, plus it would cost more. Is the interest there or not, that is the question.

Rolando


-----Original Message-----
From: Roland Christen via groups.io <chris1011@...>
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Sent: Sat, Dec 11, 2021 6:15 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Tonight I'm shooting in very clear skies, very cold sub-freezing, but poor seeing. Moon is also nearby.

Roland

-----Original Message-----
From: Eric Weiner <weinere@...>
To: main@ap-ug.groups.io
Sent: Sat, Dec 11, 2021 6:09 pm
Subject: Re: [ap-ug] M33 with 92mm Stowaway, combining RGB, H-alpha, and O-III

Thanks Roland. I have the 92FF as well. Just exploring my options. Focal length of 644 vs 488, a 1’x0.7’ delta. That’s worth the trouble of flats for some targets imho. Our skies in Colorado have been terrible so I haven’t had a chance to experiment with the TCC myself yet. I just got it on Monday.

Eric