EscapeVelocity on Nostr: Here is the 36" diameter Fraunhofer air spaced doublet refractor built by Alvan Clark ...

Here is the 36" diameter Fraunhofer air spaced doublet refractor built by Alvan Clark & Sons in the 1880s for the James Lick Observatory in Southern California. The telescope tube is 57 feet long and the whole thing weighs 12 tons. This is the 2nd largest refractor ever built and likely will remain so for all time.

https://media.nicecrew.digital/051de2bc9ad82caaeb7da9e1e13c0d6147a2484ac4773fb4c8dcfeabebbd94df.crdownload