You dodged a bullet! It's actually rare to find cemented achromats in larger sizes, because differential expansion of the two glass types will generate stress and deform the glass- sometimes enough to pop them apart and damage them. Over about 70mm, most of the quality objectives are air-spaced. One other thing to note is that there should be registration marks on the edge of both elements, so you can re-align them in the correct radial orientation. It's sometimes just a pencil mark, so hopefully you didn't remove it with your cleaning. Not all makers use indelible ink for such registration marks. Often it's just a pencil line drawn simultaneously through the edge of both elements. Also not all makers even bother. Only the higher-quality achromats will have them. On Jan 4, 2008 1:27 PM, Rob Ratkowski Photography <ratkwski@hawaii.rr.com> wrote:
Follow up
the Burgess 127 doublet is air spaced. I was about to use mineral spirits to separate the elements when I noticed a space and then remembered the 3 clear tabs. It popped apart easily and w/ some fine surgical gauze and mineral spirits, clean up began.