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HandyAndy
sage
Reged: 01/11/08
Posts: 444
Loc: West Midlands and around
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Re: The 'Best' telescope and eyepieces
07/04/08 06:15 PM
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Hi,
I was thinking of slow enough to give a Hi-Fi image.
Looking in the 'Green' book at spot diagrams and taking off-axis distances where the spot is in the Airy disk and a F no needed to get somewhere near:
Spherical Mirror F10 - 0mm
Parabolic Mirror F10 - 10mm
Flourite Refractor F8 -
Red 0mm
Green 15mm
Blue 0mm
Optimised? Schmidt-Cassegrain F 10 -
Red 0mm
Green 20mm
Blue 10mm
M C Rumak F15 - 30mm
Scheifspiegler F25 - 0mm
Can any one produce a spot diagram for a 7" F8 Makustov-Newtonian?
Obviously one can argue about the smaller colour free field of a Newtonian or a very expensive larger field of a Apochromat.
Looking at spot diagrams for eyepieces at F10 then Plossls, Abbes/Orthoscopics and Konigs give a 2 arc minute image at 10mm off axis. A Nagler type gives a 1 arc minute image at 10mm off axis as well.
Where I live my background is probably never less than 15 mag so I can resolve 2 arc minutes at most.
I can use up to 60x with the trio and 120x with the Nagler. Fortunately a Barlow lens improves things so we can get to 240x with the Nagler.
I think.
Cheers. Andrew.
--------------------
Monarch 8x42, Zeiss 10x50 WA
10mm F2, Pentax 60mm F5
City: 7" MN78: MK4#2, 10" F6.3: MK4#1, 16" F5 ParaCorr
Country: 5" F9.5, 8" VISAC: GP2
Car: 6" F5 MPCC: SP, 5" 127mm F7.5
TV 55mm, Paragon 40mm, UO Pretoria 28mm
B&L 32 Pl, Clave's 25, 8, 6, 2x
Hyperions 5, 8, 13, 17, 24, 31
Nagler1 9mm, Meade 14mm 4000 UWA
Antares 1.6x, 0.7x, 0.5x
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