Re: ATM Restoring an old Coude refractor

[Bill Marriott <btk@pacbell.net>]

Assaf;

Greetings from the group.

What to do with the achromat?

1) Send it to me  8+) mild attempt at humor.....

2) Don't be afraid to take it off the scope, collimating a refractor is
easier than dealing with a reflector.

I would recommend carefully removing the glass from the cell, noticing
any spacers or shims in the mounting assembly, as well as between the
two elements if they are not cemented. They may be oil spaced, or air
spaced.

If oil or air, spaced, clean in warm soapy water, with cotton balls,
rinseing well, to avoid any contaminates causing scratches.

If cemented, you may try separating with a solution of methylene
chloride, with 5% by volume methyl alcohol, and 5% by volume aqua
ammonia. This will separate just about anything. If there are any anti-
reflective coatings present, they may be worthless at this point if
splochy and inconsistant over the surfaces. There are chemicals that can
remove them, and if funding was available, you can have them re-coated.

Perhaps you'll be lucky and find they are from Zeiss Jena!!

A worthy project no matter what.

Bill Marriott
http://www.starlightoptical.com
telescope/optical stuff, in badly need of updating...


Assaf Berwald wrote:
> 
> Greetings to the group,
> 
> Im about to begin working on the restoration of a
> rather old 6" Coude refractor that was lying in our
> observatory for the last 30 years,

>
> A quick look at the objective lens shows what seems to
> be fungus and other spots, of which some seems to be
> on the inner side of the lenses (2 elements objective,
> to my best knoledge it is around f/15.
> I dont have the brand's name nor any info' regarding
> the optics except the fact that its a 6" coude.

> I will try to get the scope's manifecturers name from
> some of the older guys in our club. AFAIK it was made
> in Germany and held a large (70mm f15) finderscope and
> an 80mm coronograph.
> 
> Any tips and info will be greatly appriciated,
> Thanks in advance,
> Assaf B.
>