Yerkes 40" Cleaning the Front Elements

[@dantyler6907]

Since that refractor suffers from distortion due to its massive lens, I can't imagine ANY benefit using TeleVue optics. Given its age, I wonder how much the lens has effectively "flowed" over the decades it has existed.

[@dantyler1558]

A major rep from the eyepiece company thinks the access hatch is a "hat"... Spooky. Surprised this observatory did not default to TeleVue Naglers.

[@Mandragara]

f/19 telescope - slightly better correction of TeleVue eyepieces not needed. They probably use ES for the user-damage replacement program, given the scope is used for outreach. ES often also has slightly better eye relief at equal focal lengths. Say 15mm vs 18.4mm on the 24mm\68deg line

[@dantyler6907]

@@Mandragara Sounds interesting. It might be possible so many folks that use the scopes are not amateur astronomers and would not realize any benefit of TeleVue optics. Would be cool to visit the acopes and use individual eyepieces... but that is most likely not allowed. Might be an interesting tactic for TeleVue to show their superiority...

[@geocarey]

I see no cleaning.

[@dantyler6907]

The disfigured lens is most likely the main reason it's only used for outreach... Or it's close proximity to the city, no dark sky left for the scope. The scopes main value is bringing people, students into astronomy by exposing them to the "romance" of giant refractors and equatorial mounts. A giant fishing lure, used to catch students.

[@josephc6588]

Nonsense comment, this huge telescope still has value, especially since there are not enough telescope’s for all the Astronomers who might appreciate valuable time on this still functional instrument.