I am wondering how the old Vixen/Celestron 102 fluorites made in the 1980s compare to modern apo triplets? I understand they were wonderful for their day and better than many/most modern doublets, but how would they compare to modern 4" triplets from Stellarvue or William Optics for example? Anyone with first hand knowledge?
Celestron C102F vrs modern triplets?
Started by Dragonophile, 04/11/2009 11:22PM
Posted 04/11/2009 11:22PM
Opening Post
Posted 04/12/2009 06:37AM
| Edited 04/12/2009 06:38AM
#1
They compare quite favorably actually.
The color correction in the C102F (102mm F8.8)
is not quite as good as the TMB/APM airspace
triplets (100mm F8), but is fairly respectable
nonetheless. On the other hand, the color correction
is better than the popular oil-spaced AP 105mm F6
triplets -- but the F-ratio is quite different of course.
Wavefront errors were generally quite good -- on par
with the modern lenses (some better, some worse).
The fluorite element in the C102F
was uncoated, but the refractive index is low and
the curves are strong, so there is no practical
impact on contrast. The doublet cools a bit faster,
and the thin/light aluminum tube also makes for fast
cooling -- overall I would say there are less thermal
issues than thicker triplet lenses. They are wonderful
visual scopes, even by modern standards.
I haven't owned Stellavue os William Optics, so can't
make that exact comparison for you.
The color correction in the C102F (102mm F8.8)
is not quite as good as the TMB/APM airspace
triplets (100mm F8), but is fairly respectable
nonetheless. On the other hand, the color correction
is better than the popular oil-spaced AP 105mm F6
triplets -- but the F-ratio is quite different of course.
Wavefront errors were generally quite good -- on par
with the modern lenses (some better, some worse).
The fluorite element in the C102F
was uncoated, but the refractive index is low and
the curves are strong, so there is no practical
impact on contrast. The doublet cools a bit faster,
and the thin/light aluminum tube also makes for fast
cooling -- overall I would say there are less thermal
issues than thicker triplet lenses. They are wonderful
visual scopes, even by modern standards.
I haven't owned Stellavue os William Optics, so can't
make that exact comparison for you.
Funding Member
