Telescope Reviews: Declining Quality of Premium Optical Glass

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Equipment Discussions >> Refractors

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MrGrytt
scholastic sledgehammer

Reged: 07/28/05

Loc: Upstate New York

Re: Declining Quality of Premium Optical Glass new

[Re: M13 Observer]
#5535515 - 11/23/12 01:27 PM

Quote:

Quote:

"Some other telescope manufacturers use Takahashi refractors as collimating instruments for larger telescopes." - WIKIPEDIA

Alan

Another one I have left out is Zeiss.

You also left out LZOS.

Harvey

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carlcat
sage

Reged: 11/26/07

Loc: Northern California

Re: Declining Quality of Premium Optical Glass new

[Re: MrGrytt]
#5535605 - 11/23/12 02:16 PM

So, are we looking at the next wave of new refractors in the 4-6 inch range as fpl-51 triplets? Are the Orion Eons gone forever? I was kinda thinking of getting the 120 Eon some time down the line, may not happen?

Post Extras:

ValeryD
Vendor (Aries)

Reged: 11/26/05

Loc: Kherson, Ukraine.

Re: Declining Quality of Premium Optical Glass new

[Re: Tanveer Gani]
#5536613 - 11/24/12 03:08 AM

Quote:

Details would be great, Valery. Russian glass? Chinese glass? Japanese glass?

No information for public about glasses source available.

And we will try to make them affordable, at least more affordable than present apo telescopes.

We moving ahead, but much slower than we expected. However, after the first samples tests, we can increase the speed. Right now our plan is to create the new line of larger APO fluorite doublets with minimal investments in the project. Therefore the slow speed.

The only info available at this moment:

1. They will be fluorite doublets.
2. No false colors whatsoever - nor in focus, nor outside of focus
3. No any liquid inside.
4. User adjustable lenses centration.
5. 4" havy-duty two speed 1:10 focuser
6. Rotation finder position.
7. 178mm F/8.5 - the first model (in full progress).

Valery.

Post Extras:

ed_turco
Pooh-Bah

Reged: 08/29/09

Loc: Lincoln, RI

Re: Declining Quality of Premium Optical Glass [Re: ValeryD]
#5537132 - 11/24/12 11:55 AM

A bit off topic, but here goes. I see your concerns, but these rumors about BK 7 being not so hot are probably not true. The optical industry NAILED this glass down tight in production procedures and annealing. Grade A is so good, that grade B is often more than good enough. I know, I used Grade B.

Small point, maybe.

Post Extras:

ValeryD
Vendor (Aries)

Reged: 11/26/05

Loc: Kherson, Ukraine.

Re: Declining Quality of Premium Optical Glass new

[Re: Sky Muse]
#5539701 - 11/26/12 01:06 AM

Quote:

"Some other telescope manufacturers use Takahashi refractors as collimating instruments for larger telescopes." - WIKIPEDIA

Alan

Absolutely nonsense!

Post Extras:

MrGrytt
scholastic sledgehammer

Reged: 07/28/05

Loc: Upstate New York

Re: Declining Quality of Premium Optical Glass new

[Re: ValeryD]
#5539882 - 11/26/12 07:21 AM

Maybe someone has a distorted idea of what a Takahashi collimation scope is.

Harvey

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Starhawk
Post Laureate

Reged: 09/16/08

Loc: Tucson, Arizona

Re: Declining Quality of Premium Optical Glass new

[Re: MrGrytt]
#5539968 - 11/26/12 09:14 AM

What's going on is the iPhone and its ilk are using all the glass the large primes can make- it pays well, and the yield levels are very high for small blanks (yield drops with the cube of size).

They support the camera makers, whose largest blanks are 150mm, usually. So, Roland can keep 130s in continuous production. Bigger stuff won't be easy. Yuri said Prettymuch the same thing. At ASAE, he was showing a pair of beautiful RCs from his shop. The faster one was f/5.6. So, that's where he is exploring.

-Rich

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JohnH
Carpal Tunnel

Reged: 10/04/05

Loc: Squamish BC Moved!!!!!

Re: Declining Quality of Premium Optical Glass new

[Re: Tanveer Gani]
#5540111 - 11/26/12 11:07 AM

Quote:

Quote:

I think Yuri said that the glass for the miniscus was getting incredibly expensive and he did not feel that there was a sufficient interest in an expensive Mak.

The first part doesn't seem right as the meniscus is just BK7, the cheapest optical glass on the planet.

The second part I can agree with as Maks appeal to a limited segment except when it's the A-P Mak in which case everybody wants one.

Tanveer.

Now I don't feel so bad hoarding Maksutov corrector blanks.

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Sky Muse
sage

Reged: 10/26/12

Loc: De Soto County, MS

Re: Declining Quality of Premium Optical Glass new

[Re: MrGrytt]
#5540552 - 11/26/12 03:46 PM

http://en.wikipedia.org/wiki/Takahashi_Seisakusho

If taken for its word, "some" use Takahashi, the glass being either of calcium fluorite crystal or ED. The article did not specify. It's possible that Wikipedia confused the refractors for the collimator...

http://www.optcorp.com/product.aspx?pid=138-7123

...?

Alan

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MrGrytt
scholastic sledgehammer

Reged: 07/28/05

Loc: Upstate New York

Re: Declining Quality of Premium Optical Glass new

[Re: Sky Muse]
#5541136 - 11/26/12 09:53 PM

I suspect you're correct about that. The description of the collimation scope is a little misleading.

Harvey

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Sky Muse
sage

Reged: 10/26/12

Loc: De Soto County, MS

Re: Declining Quality of Premium Optical Glass new

[Re: MrGrytt]
#5541154 - 11/26/12 10:07 PM

But we have this...

"...for larger telescopes."

...not telescopes, refractors or otherwise, in general.

...odd.

Alan

Post Extras:

M13 Observer
professor emeritus

Reged: 12/09/06

Re: Declining Quality of Premium Optical Glass new

[Re: Sky Muse]
#5541222 - 11/26/12 10:45 PM

Quote:

But we have this...

"...for larger telescopes."

...not telescopes, refractors or otherwise, in general.

...odd.

Alan

This is from Wiki, and it is from a stub. It is not confirmed, nor is it a quote from Takahashi. It has not been vetted. It is quite frankly a mis-statement. Just because you read it does NOT mean it is true.

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Sky Muse
sage

Reged: 10/26/12

Loc: De Soto County, MS

Re: Declining Quality of Premium Optical Glass new

[Re: M13 Observer]
#5541318 - 11/26/12 11:32 PM

However, I seriously doubt that it was stubbed just for kicks, and insofar as it being a "mis-statement", who really knows?

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ckwastro
Pooh-Bah

Reged: 11/23/05

Loc: Tempe, AZ

Re: Declining Quality of Premium Optical Glass new

[Re: Tanveer Gani]
#5542564 - 11/27/12 06:07 PM

Quote:

The real sad day for me was when I found out that TEC was no longer making their Maks.

A friend of mine had the 10" f/20 for a while, and it was a work of art. I was disappointed as well to find out Yuri stopped making the Maks.

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plyscope
Pooh-Bah

Reged: 11/23/06

Loc: Perth, West Australia

Re: Declining Quality of Premium Optical Glass new

[Re: ckwastro]
#5542662 - 11/27/12 07:16 PM

If I'm not mistaken BK7 can be used for lenses and for mirrors but I would expect that the specifications and prices for premium optical quality would depend on the application.

Post Extras:

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