Recently saw a listing for an upgraded 102mm F/7.7 OTA (dovetail and better focuser added) for about $100. For that price, I assume it’s an ordinary achromat.
My first thought was, What if I buy this and swap out the objective with an ED doublet? Could be a fun project.
I searched online, and specifically in CN, but didn’t find mention of any companies that sell ready-to-install lenses. Is this even possible? Would it be as simple as ordering a 102mm F/7.7 doublet and installing? Would it be cheaper than buying a new 102? Thanks.
TS in Germany do sell various APO objective assemblies:
When you see the listed prices it's easy to understand why such an undertaking is not likely to be a worthwhile project if your goal is to reduce cost.
Rather, if anything, I'd probably go the other way: buy a new or lightly used run-of-the-mill ED scope and consider upgrading the focuser with the focuser harvested from the old OTA. If it's a really good focuser that alone might be worth considerably more than $100.
Edited by db2005, 11 February 2019 - 01:52 PM.