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What is the biggest true apo?

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#1 Darren Drake

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Posted 10 July 2020 - 07:46 AM

I've heard of a 12 inch lens being made by Tec but I'm not sure what the largest functional apo scope is out there??  And is it a triplet?  I would think it would have to be...  


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#2 junomike

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Posted 10 July 2020 - 08:29 AM

That's the issue.  The "Definition" of Apo.

For some that's a well corrected Doublet, for others an FPL-53 Triplet and then there's some that only find a Newt truly Apochromatic.

 

IMO it would have to be CA free on Vega, Sirirus, Etc and still be a Refractor, so maybe the TEC 250.


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#3 JuergenB

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Posted 10 July 2020 - 08:40 AM

I would estimate that the biggest one commercially available is the APM LZOS 510 mm triplet APO. (Remark: 510 mm is not its focal length grin.gif )

 

Juergen


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#4 macdonjh

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Posted 10 July 2020 - 08:55 AM

I would estimate that the biggest one commercially available is the APM LZOS 510 mm triplet APO. (Remark: 510 mm is not its focal length grin.gif )

 

Juergen

For the curious:

http://www.apm-apo.c..._6500-cnc_e.htm

 

Markus also lists some less ambitious 13" refractors as well...


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#5 TNmike

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Posted 10 July 2020 - 08:56 AM

Gulp!



#6 OldManSky

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Posted 10 July 2020 - 09:08 AM

That's the issue.  The "Definition" of Apo.

For some that's a well corrected Doublet, for others an FPL-53 Triplet and then there's some that only find a Newt truly Apochromatic.

 

IMO it would have to be CA free on Vega, Sirirus, Etc and still be a Refractor, so maybe the TEC 250.

I'm gonna need a bigger observatory...


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#7 Eliserpens

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Posted 10 July 2020 - 09:14 AM

 

I would estimate that the biggest one commercially available is the APM LZOS 510 mm triplet APO. (Remark: 510 mm is not its focal length grin.gif )

 

Juergen

.. which is 6500mm.  Finding stuff will be fun....


Edited by Eliserpens, 10 July 2020 - 09:15 AM.


#8 Moondust

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Posted 10 July 2020 - 09:25 AM

.. which is 6500mm.  Finding stuff will be fun....

Not exactly a great candidate for the Vixen HR's  Eyecrazy.gif


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#9 psychwolf

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Posted 10 July 2020 - 09:27 AM

Seems like this question gets asked a lot on here as maybe the ultimate end of aperture fever (at least for a few years) - the answer was the Keck Twins a few years back, so likely something bigger by now? 

 

https://www.cloudyni...-apo-ever-made/

 

Status report.. still the biggest?


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#10 donadani

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Posted 10 July 2020 - 09:44 AM

maybe better ask for the "biggest apo reaching embient in a usefull time" :D


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#11 jag767

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Posted 10 July 2020 - 11:13 AM

510mm..... wow! I guess that answers the question of what happens if I win Powerball πŸ˜‚.

#12 Jeff B

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Posted 10 July 2020 - 11:28 AM

I suspect that if you can afford a custom made LZOS 510mm aperture triplet, you can also afford to condition the air inside the observatory to a couple degrees below ambient, mitigating thermal issues with the objective.  I'd like to see some pictures of its installation though.

 

I do know Markus also did a 12" LZOS bino-scope.

 

Jeff


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#13 Cliff C

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Posted 10 July 2020 - 12:23 PM

I believe that Tinsley Labrotories made a 20" in the early sixties. There was an ad in sky and telescope showing it but I believe that it never produced good results.



#14 Eliserpens

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Posted 10 July 2020 - 01:02 PM

How much do these scopes weigh?  My 312mm f2064mm dob-mounted Serrurier (75lb) is looking pretty good now...


Edited by Eliserpens, 10 July 2020 - 03:35 PM.


#15 Supernova74

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Posted 10 July 2020 - 01:06 PM

how about a pair of 12” APO binoculars 

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Edited by Supernova74, 10 July 2020 - 01:08 PM.

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#16 Astrojensen

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Posted 10 July 2020 - 01:07 PM

How much do these scopes weigh?  My 312mm f2064mm dob (75lb) is looking pretty good now...

They are HEAVY. We're probably talking an 800lbs tube, if not more, for a 20" apo. The lens cell alone weighs 120kg/264lbs...

 

https://www.professi...-51cm-Giant-Apo

 

 

Clear skies!
Thomas, Denmark


Edited by Astrojensen, 10 July 2020 - 01:10 PM.

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#17 Astrojensen

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Posted 10 July 2020 - 01:09 PM

how about a pair of 12” APO binoculars 

Such a thing exists, believe it or not. Order one today, if you want.

 

https://www.professi...30cm-Super-Bino

 

 

Clear skies!
Thomas, Denmark


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#18 psychwolf

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Posted 10 July 2020 - 01:36 PM

Such a thing exists, believe it or not. Order one today, if you want.

 

https://www.professi...30cm-Super-Bino

 

 

Clear skies!
Thomas, Denmark

Total weight is only 2,000lbs, and at 400kg they're definately pushing it beyond 20% of the mount's rated capacity right? What a bunch of amateurs... psh*  

 

*sarcasm is being used here, I'm not being serious.


Edited by psychwolf, 10 July 2020 - 01:39 PM.

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#19 Jarno

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Posted 11 July 2020 - 11:40 AM

how about a pair of 12” APO binoculars 

 

Such a thing exists, believe it or not. Order one today, if you want.

 

https://www.professi...30cm-Super-Bino

 

 

I might order one but only if it can be used hand-held. grin.gif

 

Jarno
 


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#20 Alrakis

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Posted 11 July 2020 - 12:39 PM

Not sure how accurate it is, but this giant lens database is fun to look through:

 

http://alag3.mfa.kfk...enses/index.htm

 

It indicates that there is a LZOS 356mm triplet APO, a 425mm APO Camera lens (425mm f/4, with a focal length of 1700mm), and a 650mm Zeiss APO telescope in Belgrade.

 

Does anyone have information on the 650mm Zeiss APO. Just curious as to how it was made, what the lens design is, etc.

 

Chris


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#21 Supernova74

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Posted 11 July 2020 - 01:21 PM

how about a pair of 12” APO binoculars 

Hi guys yes it’s my friend Steffos getting my binoculars ready for a nights observing yeah right if you believe that would believe in the tooth fairy lol.(think I heard somewhere thay are yours for $250,000-300,000 respectively ps if anyone like to know thay weigh in at around 4000kg


Edited by Supernova74, 11 July 2020 - 01:23 PM.


#22 Astrojensen

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Posted 11 July 2020 - 01:22 PM

 

Does anyone have information on the 650mm Zeiss APO. Just curious as to how it was made, what the lens design is, etc.

 

Chris

It's a typo. The 650mm Zeiss at Belgrade Observatory is a normal achromat. 

 

 

Clear skies!

Thomas, Denmark



#23 SeymoreStars

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Posted 11 July 2020 - 01:26 PM

20170408 102012

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#24 Spikey131

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Posted 11 July 2020 - 02:56 PM

So who do you think buys a 20” f12 6500mm refractor?  And for what application?



#25 junomike

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Posted 11 July 2020 - 03:00 PM

So who do you think buys a 20” f12 6500mm refractor?  And for what application?

The "Rich" and "just because"........




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