Does anyone know of an optical company that can do this job?
Recementing a 3" Achromatic objective
Posted 04 May 2021 - 04:40 PM
I know there are companies that do it because the previous owner of my TMB 80 SS triplet had it fixed from the same problem. He never told me the company's name but said it was a larger well known optical company.
Posted 04 May 2021 - 05:21 PM
For the heck of it, could always try air-spacing in the interim.
Posted 04 May 2021 - 05:52 PM
If using UV cured adhesive such as NOA61 its important that UV illumination non uniformity across the adhesive layer be less than 10% or measurable aberrations due to index gradients etc within the cured adhesive layer will occur. Similar non uniformities when using optical epoxies can also occur if the epoxy is left on the first element for more than a few seconds before the second element makes contact.:
Posted 05 May 2021 - 07:25 AM
De-cementing it is probably the crux. You could air space it, or oil it. Usually 3" is a practical limit for cementing. We have a 4" triplet made by Stan Brower...found it in a junk box. It star tests horribly...big astigmatism, the cementing has bubbles/voids. One of our members got excited at the find and started a formal build, cell, focuser. I slapped together a tube to test it out, and it has now never been in use.
It would be interesting to de-cement it and redo it. It hasn't come up near the top of anyone's "to do" list. Older Balsam cemented lenses come apart with heat and solvent...I have no idea how to de-cement something with the newer polymer cements.