Largest APO built in the last ~10 years?

Valery,
Yes, but I do not think Markus would risk a fortune of his own money if
the opticians at LZOS did not think there is a high probability of
success in this endeavor. I wish them the best.


Tom Mack

On Fri, 14 Jan 2005 02:17:12 +0000, "Richard F.L.R. Snashall"
wrote:



RichA wrote:



It's good that this is all speculation. Because if anyone were
going to spend the kind of money that would take, they could
invest in any kind of reflector, get a better instrument for
what, about 1/5th the cost? And the mirror could be larger too.

Let me guess... you like reflectors over refractors?

-Rich

I like refractors to about 6." After that, the prices are insane,
as are the mounts, the housing needed, etc.
-Rich

There is the ARIES 12" Fluorite doublet (in Japan) and it does work.
14" (kurtz-flint based) triplet APO by LZOS still wait it's buyer.

nonsense, the 14" was sold and shipped long time ago to Korean customer

How it will performs under sky is still a question. Thermal problems
can be significant.
As for 21". There is no warranty, that it will be succesfully realized
and that it will really work - again thermal problems and figure
stability (due to gravity).

nonsense again, the 21" Apo will be done and shipped till end of 2006,
if you want to see how it works come then over to Germany :-)

LZOS can do at this moment Super ED Apos up to 330 mm diameter and the
melting department is working on getting larger blanks. The expected max
size will be somewhat between 14 inch and 16" correspondance to the lZOS
melting department

Markus


VD




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On Sat, 15 Jan 2005 12:33:29 +0000 (UTC), "Markus Ludes"
wrote:



There is the ARIES 12" Fluorite doublet (in Japan) and it does work.
14" (kurtz-flint based) triplet APO by LZOS still wait it's buyer.

nonsense, the 14" was sold and shipped long time ago to Korean customer

How it will performs under sky is still a question. Thermal problems
can be significant.
As for 21". There is no warranty, that it will be succesfully realized
and that it will really work - again thermal problems and figure
stability (due to gravity).

nonsense again, the 21" Apo will be done and shipped till end of 2006,
if you want to see how it works come then over to Germany :-)

Just out of curiosity, why would someone buy one of those?
-Rich

Subject: Largest APO built in the last ~10 years?
From: RichA
Date: 1/15/2005 6:51 PM Eastern Standard Time
Message-id:



Just out of curiosity, why would someone buy one of those?
-Rich
****************************
I guess for bragging rites. If i had the money and space, i would take a 21"
APO say around F/10!!!

Chas P.

Is this ads in the AstroMart was your one? This ads claimed, that due
to constant
unrealistic promises of the original customer to pay the balance, you
decided to
put the ads on the AM for free selling?
As I remember, this was at the end of the year 2004.

As for 21" - flag in your hands! But I don't beieve, that if it will
be triplet, it will
work under the real sky - problems with thermal equilibrium with
enviroment air,
following temperature fall, figure stability due to gravity forces.

IMHO, the limit size of a trouble-free APO will be 16" doublet.
Doublet with OK-4
is a bit problematic because of adequate mate element.
The reason I think so about limit size is that I used 16" F/15 Zeiss
refractor for
several evenings. It tooks about three hours to reach acceptable
figure after the
dome was opened. During evenings with rapid temperature fall, this
refractor never
worked at it's best.


However, I wish you a success with 21" project - may be I will have a
chance to
look through it during next Mars apparition.

VD

The 15 inch refractor, formally at the Dominion Observatory in Ottawa
Canada had its original achromatic lens replaced with a triplet apochromat
lens several years ago. The telescope is now at the Helen Hogg Observatory
which is part of the Canada Science & Technology Museum in Ottawa. It is
open for public viewing. See: www.science-tech.nmstc.ca