“I am the only person to ever ace a 1951 USAF resolution test. My 'to observe' list says 'done'. I do not use charts or atlases when I starhop; men do not use maps. One of my sketches won an SBIG deep sky imaging contest. I am the life of star parties I have never attended. I never say anything looks like a faint fuzzy - not even a faint fuzzy. Pilots aim green laser pointers at me. Don Pensack proofreads my CN forum posts.” - The Most Interesting Astronomer in the Universe
Quote:So they really are different kettles of fish. So for certain purposes (planetary and lunar observing and brighter double stars where there's plentiful light from the target) the two types of instruments (faster ED 80mm doublets and triplets and the C90) perform almost equivalently
Whenever I have come into large sums of money in my life, I always put half of it aside to spend on fast cars and the pursuit of loose women.
I put aside the other half to spend frivolously.
Quote:And yet, head to head field comparison of the C90, AT72ED and Carton 60mm f/16.7 achromat, and AT60EDT show this not to be the case. The C90 outperforms all three of them on double stars and planets. I have several more 3" and 2.4" refractors at my disposal, as well as a C5. Maybe I had bad luck with mine, but the C5 is a dog. My C6, on the other hand, is a very decent scope.- Jim
Quote:And yet, head to head field comparison of the C90, AT72ED and Carton 60mm f/16.7 achromat, and AT60EDT show this not to be the case. The C90 outperforms all three of them on double stars and planets.
Kmart 40mm-Thanks Mom|Jason60mm-Thanks Dad|C80SS-Thanks Wife|C90|C102|C6XLT|AP130EDFGT|C-11XLT EQ-2|EQ-3|CG5GT|Mach 1 & Eagle "For once you have tasted flight, you will walk the earth with your eyes turned skywards, for there you have been and there you will long to return".-Leonardo da Vinci "We're all in the gutter, but some of us are looking at the stars."-Oscar Wilde ~RIP Dad, you were my best friend...Godspeed!~
East/Central Illinois Orion XT10 AstroTech 72ED AstroTech 102ED Celestron XLT120
Quote:My math, based on the fact that this apparently has standard coatings and a 32% CO, says that the light through put would be comparable to a 76mm refractor. In terms of planetary viewing, the 32% CO would reduce the planetary contrast significantly more... the old rule of thumb suggests that it would be the equivalent of a 60-70mm refractor...
C10NGT, Z8, 150 Rumak, XLT 150, C6, C5, SW5 Newt, 4.5 Ball, C102GT, C90, ST80, A70LF; 15x70, 25x100; Burgess BV; Paracorr II; T6 2.5, XO 2.58/5.1, Ethos-SX 3.7, Delos 4.5, TV Plossl 7.4-26, BCO 10, Hutech HC 12.5, Sterling 12.5-25, ES100 14, CZJ H 16/25, CZJ O 16, M5k UWA 24, T5 31, Ultrascopic 35, Titan-II 40; Bino Pairs M5k UWA 6.7, Baader Zoom 8-24, M5k SWA 24, TV Plossl 26, RKE 28.7; Zooms NZ 2-4, NZ 3-6, Leica ASPH 8.9-17.8, Baader 8-24; Baader Zoom Barlow, VIP Barlow
Quote:Last year I took a test drive with that old rubber armored C90 and much to my suprise...It blew away the 80mm. Really! I was amazed at how much better it resolved planetary/lunar detail and its ability to go to 200x was appreciated. Color free to boot.