It is coming up on 20 years since Mr. Christen gave us the Super Planetary design using BaK-1, KzFSN-4, & BaFN-10 in TM#28. While this triplet leaves nothing to be desired as to performance visually, is there anything today either economically or technologically, that might make for an updated super planetary design? If Mr. Christen presented such an article in 2005, would different glass be used and why?
Any new apo designs?
Started by khking, 09/20/2005 04:23PM
Posted 09/20/2005 04:23PM
Opening Post
Posted 09/20/2005 06:02PM
#1
Well, there are many lens designs now using Fluoro-crown
glasses like FPL-52 and FPL-53; even the Chinese have
caught on. Fluorite is in wide use.
Look at the tests at
http://forum.astronomie.de/phpapps/ubbthreads/showflat.php?Cat=&Number=326292
for the Tak TOA-130. Very hard to see any color in
the patterns compared to other scopes.
I just got an APM / TMB 130 F9. I do not know the
glasses, but I can say it is hard to see any false color
even in the out-of-focus patterns on Vega. There is
less color than any other refractor I have used, including
AP 155 and AP 160 (OK, these are larger aperture). Maybe
inside best focus the outer Fresnel ring has the slightest
orange tint compared to outside best focus.
So yes, APO progress goes on; there are very nice new designs.
glasses like FPL-52 and FPL-53; even the Chinese have
caught on. Fluorite is in wide use.
Look at the tests at
http://forum.astronomie.de/phpapps/ubbthreads/showflat.php?Cat=&Number=326292
for the Tak TOA-130. Very hard to see any color in
the patterns compared to other scopes.
I just got an APM / TMB 130 F9. I do not know the
glasses, but I can say it is hard to see any false color
even in the out-of-focus patterns on Vega. There is
less color than any other refractor I have used, including
AP 155 and AP 160 (OK, these are larger aperture). Maybe
inside best focus the outer Fresnel ring has the slightest
orange tint compared to outside best focus.
So yes, APO progress goes on; there are very nice new designs.
Funding Member
