130514 Telescope Workshop notes, May 14, 2013
Attendees: TomK, EdK, JerryW, TomT, DmitriiZ, TimC, TomW, EdEd, JoeD, John/Shah
-SBAU 42” tv was on table in Broder, but needed remote to change source.
DZ-working on polishing mirror. Cerium oxide solution using new pitch poured by TomW using a silicone mold.
TW- brought in his testing equipment. Testing 6” mirror, F9, 108” test length across two tables tonight.
-Then 14.5” mirror of TomW put on stand. Ronchi patterns shown of desired final test pattern.
-Then DZ 12” mirror currently being polished placed on stand at 910pm. 106” test length. TomW calls the pattern an oblate sphere, needing to carve/polish out center more. Foucault test (razor edge) test to see the “two mirrors” more clearly. DZ and TT taking photos/videos of patterns.
TimC--re: Tinkerer Festival, July 2l: TimC has grinding stroke poster; EdEd pictures and 1950 style 4.5” telescope, old telescope making books; JW will bring another mirror blank and wood grinding stand, TimC will provide grit stuff; SBAU tv with looping videos of mirror grinding by DZ,TT.
JW, EdEd, DZ talking to John/Shah on how to’s of grinding & making telescope.
TimC&EdEd to TomT-centuries ago mirrors were polished metal. Then 1860 glass was coated w silver. Amateurs in 1950s would deposit silver precipitate onto their polished glass. Today, .99999 pure Aluminum is sputtered on, then a coating of SiO2.
Bill Clausen wants lights out and doors open to let out any flies that otherwise can set off Broder alarms.
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