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So what high end 6-8'' apo refractors do cover full frame?

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#1 dron2015

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Posted 21 October 2021 - 08:39 PM

Dear CN Fellows,

 

Hope that all is well!

 

Have been thinking about domesticating another apo 6-8'' refractor . Who do I fool - surely 7'' is the max for my budget. My intention is purely astrophotography w/ full frame.  Which refractor is the best in this category? it could be w/ paired flattener and/or reducer. if so, back focus distance of reducer/flattener should allow long optical train - OAG + filters+ camera.  Weight - does not matter.

 

Main criteria - covering Full sensor s with pin point stars in all corners and without any issues. looking forward with widely open eyes full of hope - can any 6-8'' refractor cover 16803?

 

photo prove is much appreciated!

 

Best,

Andrey



#2 D_talley

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Posted 21 October 2021 - 09:15 PM

Not quite 6 inches, the TEC 140 with flattener will cover my Apogee F16M camera which is the 16803 chip. 

 

http://49411959282_470ee6e744_h.jpg2020-F16M-Rosette-Nebula_Web by dwight_talley, on Flickr


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#3 dron2015

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Posted 21 October 2021 - 09:17 PM

Not quite 6 inches, the TEC 140 with flattener will cover my Apogee F16M camera which is the 16803 chip. 

 

http://2020-F16M-Rosette-Nebula_Web by dwight_talley, on Flickr

 

 

WOW!!! just WOW!!!



#4 chanrobi

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Posted 21 October 2021 - 10:46 PM

Not quite 6 inches, the TEC 140 with flattener will cover my Apogee F16M camera which is the 16803 chip. 

 

http://49411959282_470ee6e744_h.jpg2020-F16M-Rosette-Nebula_Web by dwight_talley, on Flickr

Bruh I don't think that pic is high res enough



#5 Sleep Deprived

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Posted 21 October 2021 - 10:48 PM

Not quite 6 inches, the TEC 140 with flattener will cover my Apogee F16M camera which is the 16803 chip. 

 

How did you get time on the Hubble????  I've been trying to do that for years!


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#6 gpsfool

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Posted 21 October 2021 - 10:53 PM

Hey Dwight - that’s one nice photo!

 

Gpsfool



#7 D_talley

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Posted 21 October 2021 - 11:03 PM

Thanks. The image is a little crunchy because of the size restrictions but that scope does a great job filling up the chip on that camera.  Just about every object fills the chip correctly without having to crop much. 


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#8 dron2015

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Posted 21 October 2021 - 11:23 PM

so is TEC 140 the absolute winner then in this category?



#9 Sleep Deprived

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Posted 22 October 2021 - 01:42 AM

If interested in the TEC, but wondering about the TEC160 instead of the 140, you may want to read this thread from a while back:

 

https://www.cloudyni...ec-140-vrs-160/

 

You can decide for yourself, but my impression was that the 140 was preferred over the 160.


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#10 edif300

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Posted 22 October 2021 - 03:30 AM

Takahashi TOA can cover perfectly the 16803 format with TOA67Fl flattener:

 

Corners at 100%:

http://www.astrosurf...m_Butterfly.jpg

 

Image:

http://www.astrosurf...OA67FF_U16m.jpg

 

Going to end of page:

http://www.astrosurf...Ha_TOA_U16m.htm

 

Those scopes (F7-F8) are little slow for *nomadic* astrophotography...


Edited by edif300, 22 October 2021 - 03:31 AM.

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#11 rockstarbill

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Posted 22 October 2021 - 04:50 AM

TOA150 + new TOA645 Flattener gets you 1-5um spots across a 60mm corrected field. I'm not aware of any other 6" refractor that can do that. Same impressive spec applies to the smaller TOA130, using the same new flattener.

Edited by rockstarbill, 22 October 2021 - 04:57 AM.

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#12 coinboy1

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Posted 22 October 2021 - 05:36 AM

That new TOA645 flattener is pretty impressive, I saw the spots on that thing. It is sharp! 


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#13 rockstarbill

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Posted 22 October 2021 - 05:39 AM

That new TOA645 flattener is pretty impressive, I saw the spots on that thing. It is sharp!


I have one incoming. Looking forward to testing it out!
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#14 coinboy1

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Posted 22 October 2021 - 06:00 AM

Let me know how it is with your 16803 chip! Very curious!


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#15 edif300

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Posted 22 October 2021 - 06:51 AM

TOA150 + new TOA645 Flattener gets you 1-5um spots across a 60mm corrected field. I'm not aware of any other 6" refractor that can do that. Same impressive spec applies to the smaller TOA130, using the same new flattener.



I still didn’t test it… so no images…

Its in M72 and small metal back distance. Probably these features will open the 645 flattener’s compatibility to other scopes. Its a pitty the lost of M92 with 106.2mm MBD “rule” …. more custom made couplers …
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#16 rockstarbill

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Posted 22 October 2021 - 07:03 AM

I still didn’t test it… so no images…

Its in M72 and small metal back distance. Probably these features will open the 645 flattener’s compatibility to other scopes. Its a pitty the lost of M92 with 106.2mm MBD “rule” …. more custom made couplers …


I think there's still good reason to have the 67 Flattener as well. The really generous backfocus on that can be useful with certain configurations. It's also 3 microns on axis and 20 microns at the edge of the massive 90mm field. So performance of the 67 is still excellent.

As for other scopes, I plan to compare it to the AP flattener on the GTX scope as well. Very curious to see if there's any real change over the AP flattener, which works really well as is.

#17 drprovi57

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Posted 22 October 2021 - 09:48 AM

CFF 200mm F/6.5 with CFF dedicated field flattener (98mm of BF) - covers full frame.  If you want perfect round stars in the very corners you will need a Tilt Adjuster (I have one).  Today’s CMOS full-frame camera’s are not perfectly flat chips.

 

Jason


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#18 dron2015

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Posted 22 October 2021 - 12:09 PM

Takahashi TOA can cover perfectly the 16803 format with TOA67Fl flattener:

 

Corners at 100%:

http://www.astrosurf...m_Butterfly.jpg

 

Image:

http://www.astrosurf...OA67FF_U16m.jpg

 

Going to end of page:

http://www.astrosurf...Ha_TOA_U16m.htm

 

Those scopes (F7-F8) are little slow for *nomadic* astrophotography...

 

Iñaki. thanks much!

 

It seems that TOA-150B + flattener/reducer is the way to go. two more questions (stupid ones)

1. Does anyone have a color photo? for some reason found only a couple photos on astro bin with TOA 150B and QHY600/ASI6200/16803

2. (a little bit off topic) what do you usually do with wi Tak stock focuser? Please excuse my ignorance - never had a TAK. Are you attaching some motor? or remove it and put another (WR35, FT3.5)? I assume that all these flatteners designed to pair perfectly with TAK stock focuser  - so which motor are you using?

 

Best,

Andrey


Edited by dron2015, 22 October 2021 - 12:15 PM.


#19 dron2015

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Posted 22 October 2021 - 12:17 PM

TOA150 + new TOA645 Flattener gets you 1-5um spots across a 60mm corrected field. I'm not aware of any other 6" refractor that can do that. Same impressive spec applies to the smaller TOA130, using the same new flattener.

 Rockstarbill, thanks much!

 

if you do not mind - which scope do you love more for DSO  TOA 150B vs  Planewave CDK 14''? it seems that you have been using both.



#20 rockstarbill

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Posted 22 October 2021 - 12:20 PM

Rockstarbill, thanks much!

if you do not mind - which scope do you love more for DSO TOA 150B vs Planewave CDK 14''? it seems that you have been using both.


The Planewave is on order. Best scope for long focal length I have is the AG 12.5". refractor I would lean AP GTX first but the new TOA flattener could change that.
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#21 edif300

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Posted 22 October 2021 - 01:01 PM

Iñaki. thanks much!

It seems that TOA-150B + flattener/reducer is the way to go. two more questions (stupid ones)
1. Does anyone have a color photo? for some reason found only a couple photos on astro bin with TOA 150B and QHY600/ASI6200/16803
2. (a little bit off topic) what do you usually do with wi Tak stock focuser? Please excuse my ignorance - never had a TAK. Are you attaching some motor? or remove it and put another (WR35, FT3.5)? I assume that all these flatteners designed to pair perfectly with TAK stock focuser - so which motor are you using?

Best,
Andrey

Hi Andrey,

My friend Richard Galli is an APOteam member, own a TOA-150 and U16m camera (16803) in a remote observatory in Chile. You can find their job here:

http://www.atacama-p...om/index_EN.php

Usually the stock focuser with Robofocus via focusmax. It works fine to my:

https://www.cloudyni...itis/?p=8467159

Edited by edif300, 22 October 2021 - 01:45 PM.

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#22 Raginar

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Posted 22 October 2021 - 01:25 PM

Dear CN Fellows,

 

Hope that all is well!

 

Have been thinking about domesticating another apo 6-8'' refractor . Who do I fool - surely 7'' is the max for my budget. My intention is purely astrophotography w/ full frame.  Which refractor is the best in this category? it could be w/ paired flattener and/or reducer. if so, back focus distance of reducer/flattener should allow long optical train - OAG + filters+ camera.  Weight - does not matter.

 

Main criteria - covering Full sensor s with pin point stars in all corners and without any issues. looking forward with widely open eyes full of hope - can any 6-8'' refractor cover 16803?

 

photo prove is much appreciated!

 

Best,

Andrey

My ES152 CF doesn't have any issues covering a full frame sensor (D810 and a QHY16200).  Both the focal reducer and straight through works well enough.  Technically you want a 1.0x FF (TS makes one) for native focal length (I have one, haven't used it, it's hardly noticable).  The focuser is trash; I use a nitecrawler.  You need the flanger extension and a 2" spacer to make it work.  

 

Photos are on my phone; if you PM me your email I can send them to you.

 

I really like it.


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#23 dron2015

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Posted 22 October 2021 - 01:42 PM

My ES152 CF doesn't have any issues covering a full frame sensor (D810 and a QHY16200).  Both the focal reducer and straight through works well enough.  Technically you want a 1.0x FF (TS makes one) for native focal length (I have one, haven't used it, it's hardly noticable).  The focuser is trash; I use a nitecrawler.  You need the flanger extension and a 2" spacer to make it work.  

 

Photos are on my phone; if you PM me your email I can send them to you.

 

I really like it.

Raginar,

 

16200 is a great sensor, but it is not excatly full size - its diagonal is about 36mm.  Nikon 810 - seems to be 36x24 full frame sensor.  Great to know that ES152 CF can deliver full frame picture!


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#24 Raginar

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Posted 22 October 2021 - 01:58 PM

Raginar,

 

16200 is a great sensor, but it is not excatly full size - its diagonal is about 36mm.  Nikon 810 - seems to be 36x24 full frame sensor.  Great to know that ES152 CF can deliver full frame picture!

 

I've been super surprised by this scope.  I usually aim for higher end scopes (my other imaging scope is a Tak106, I'd like an AG10 at some point) and I've been really happy with it.  The CF makes a huge weight difference; and the glass is solid. 

 

Shoot me a PM and I'll send you some FITS files to analyze; the reducer is a known 'not great' product.  I think if I was doing it again I would've bought a TS reducer as well.  


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#25 rockstarbill

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Posted 24 October 2021 - 02:24 AM

Iñaki. thanks much!

 

It seems that TOA-150B + flattener/reducer is the way to go. two more questions (stupid ones)

1. Does anyone have a color photo? for some reason found only a couple photos on astro bin with TOA 150B and QHY600/ASI6200/16803

2. (a little bit off topic) what do you usually do with wi Tak stock focuser? Please excuse my ignorance - never had a TAK. Are you attaching some motor? or remove it and put another (WR35, FT3.5)? I assume that all these flatteners designed to pair perfectly with TAK stock focuser  - so which motor are you using?

 

Best,

Andrey

I will have some photos with the QHY268M and FLI 16803 on the TOA150B as soon as I can get the sky to clear out. I do not have my IMX455 chip camera yet. That will probably be another month or so. I should have both the TOA67 and TOA645 flatteners to test as well. I should mention that the Reducer 0.7x for the TOA series does not work well with small pixel full frame cameras. The older 645 TOA reducer might work a little better, but it was discontinued and is very hard to find. I am hoping they make a new 645 reducer with smaller spots that are more suitable for modern CMOS chips. 

 

I really want to use the stock focuser on the TOA150B. It is very nice, and has a manual camera rotator on it that is very sturdy. For motorization I put on the Sesto Senso 2 motor from Primaluce Lab. It connects up nicely to the stock focuser with no need for extra adapters, since the TOA150B focuser shaft is 25mm. If you get one and do the same be sure to use the gold bushing and not the green one. The gold bushing allows for the grub screws to set in fully, which is important when you connect the motor to it. The green one they don't seat in fully and will prevent the motor connection from seating all the way in. 

 

I just need some clear skies to test out the TOA150B as I have it now. I am optimistic it will work well.


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