I'm trying to construct a refractor with a 4 element design based on the "Petzval" concept where a two element air spaced objective lens at the front of the telescope passes the light through to a second doublet lens positioned at the rear of the telescope and before the focuser. The doublet lens group functions to 1) reduce the effective focal length, and 2) reduce or eliminate curvature of field.

See this site for details:

http://www.company7.com/televue/telescopes/tv101.html

I am aware of how to construct a refractor (baffles, collimation, etc)and know my home made job won't work like a REAL TeleVue, but it seems like a fun project.

I just need a recommendation on what spaceing and fl "second" lens to use with my 102mm f12 air spaced doublet Objective - I already have 2 80mm cemented doublets (a 400mm and 600mm focal lengths) and I was wondering if I could use one of them?

Thanks

Joe

• Oh, boy! - bobmay - June 1, 2001 - 07:30 UTC
  • Thanks - Yes I searched on the web - jgarzione - June 1, 2001 - 18:26 UTC
    • Petzval designs - bobmay - June 3, 2001 - 19:13 UTC