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Started by daniela, 01/19/2009 10:42AM
Posted 01/19/2009 10:42AM Opening Post
Hello, I bought some time ago from a friend of mine a Zeiss 50/540 lens in cell. We believe it to be a C50/540. Now I would like to get it intubated and I received a call from the shop, if I am going to view straight-through or if the tube should be short enough for a diagonal and which optical length. I believe they were meant to use for straight-through viewing, as I believe Zeiss prism diagonal were M44 and had matched spherical aberration that corrected the residue of bigger instruments. However I would think they are not suited to a 50mm f/11. I would also have some other diagonals, the most old-fashioned are a .965" and a 1.25" prism diagonal. Your valued opinion would be most welcome. Thanks a lot in advance, Daniela
Posted 01/27/2009 04:01PM #1

what you want to do with the lens ? Build a finder, then do it maybe straight with a 2" focuser for 2" eyepueces, or build a real telescope , then you need to select first a focuser

if you want to use a stardiagonal the backfocuse shall be about 130 mm behind end of fully racked in focuser so you can use any normal eyepieces


clear skies

Markus Ludes
Posted 02/06/2009 01:32AM | Edited 02/06/2009 01:34AM #2
Hello Daniela,

I have a C50/540 that I use with a Borg Series 80 tube and focuser. This is Borg Part #6000. I had Ashley Stevens from PreciseParts make a special adapter that holds the Zeiss lens and screws into the Borg's threads. Ashley is an artist with a lathe - it was not cheap in the end, but it is a great little telescope. I am hoping to use it with a LSS Ha filter someday.

best regards,