Cracking apart an 8 inch lens!!!!!!

Hello,

This is my first post to this group.

I have a rather worrying task ahead of me and would welcome any advice before I commnence.

I have obtained an 8 inch triplet lens, made by Cooke, Troughton & Simms. It has a nice cell, glass looks very good and has an F ratio of about 15.

The problem is that it has been cemented with Canada Balsam. I would like to separate the elements, and have it re-figured if necessary.

I know that in the past, elements have been separated by 'boiling' the lens in a pan hot water (slowing bringing up the temperature of the water to prevent any suddern shock to the lens).

Has anyone out there undertaken this proceedure? What is the ideal temperature that the basam will start to flow?

I hope someone can help.

Many thanks


Sean

Thanks Tom,

It is a Photo-Visual lens. On the cell is marked Number 81. I believe it was made around 1940. Lens technology is now vastly improved - this one has a few bubbles in the glass!

I don't know why it was cemented - it may have been for a non astronomical purpose - the elements are separated by foil spacers.

This was definitely not a periscope lens!

Some photos of this process would be interresting and appreciated if ya gots a camera and the time. Best of luck.
Robert

Here is an article that may give you some information about your lens.

< http://sci.tech-archive.net/Archive/sci.astro.amateur/2004-12/0671.html >