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Tom L
Reged: 01/07/04
Posts: 29792
Loc: Sunny Oregon
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This post is for capturing the best posts made by members and to preserve them. If you see a post you like, send an PM to one of the Eyepiece forum moderators to consider adding a post to this thread.
Thanks!
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Tom 
Tele Vue 102mm f/8.6 on an EzTouch
Vixen 80mm f/5 A80SSWT on a grab-n-go mount
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Tom L
Reged: 01/07/04
Posts: 29792
Loc: Sunny Oregon
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AFOV vs. TFOV
Cleaning Eyepieces
Determining Eyepiece Focal Length
Eyepiece Designs, Aberrations, etc.: Links
Eyepiece Fieldstop Spreadsheet
Eyepiece FOV and POWER by star drift method....
Poll: How Many Eyepieces Do You Have?
How to measure/calculate Apparent Field of View.
Original Best of Thread
Planetary Eyepiece Comparison
Pupil dilation vs. sky darkness
So, What's in Your Eyepiece Case?
This is the original thread that has now been locked; but can still be read
So, What's in your Eyepiece Case, Restart
Useful Formulas
Useful Magnification Ranges
Threads about individual eyepiece models
Orion Stratus & Baader Hyperion
LVW Clones?
With possible variations in glass type and coatings, these appear to be very similar eyepieces.
An in depth comparison of these lines.
This shows that the structure of these lines is very similar, possibly identical at the shorter focal lengths. Shows conclusively that the coatings of the Hyperions and Stratus differ, though advantage was only seen in the longer focal lengths. Thanks to Sven and Amalia.
Masuyama Eyepiece Thread
Synopsis of the various Masuyama clones.
Pretoria Eyepiece thread (with pictures!)
These eyepieces were made in the 80's and are quite rare today.
Formulas
Focal Ratio (F Number) = Telescope FL(mm)/Aperture(mm)
Magnification (Power) = Telescope FL(mm)/Eyepiece FL(mm)
Exit Pupil (mm) = Aperture(mm)/Magnification
Resolution (arc seconds)
Dawe's Limit (elongated double star) = 0.12/Aperture(meters)
Rayleigh Limit (split double star) = 0.13/Aperture(meters)
Field of View (degrees)
Measured F.O.V. = 15 X Time (seconds) X cosine(Declination)
Calculated F.O.V. = EP Apparent F.O.V./Magnification
EP=Eyepiece; F.O.V.=Field of View; FL=Focal Length
1m=1000mm=39.37 inches = 3.28 feet; 1"=25.4mm; 1mm=.039"
Edited by csa/montana (05/17/08 03:37 PM)
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csa/montana
Astro Ambassador
Reged: 05/14/05
Posts: 26974
Loc: montana
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Eyepiece distance from eye:
http://www.cloudynights.com/ubbthreads/showthreaded.php/Number/2302103/
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Carol
AstroTech 16" Dob (Thanks ASTRONOMICS!)
AstroTech 66ED / Vixen 80MF/AstroTech Voyager
Masuyama's 7.5, 15, 25W, 35mm,
Tak LE 5mm
7mm Pentax XL, 10mm Pentax XW
14mm Meade 4000 UWA
22mm Pan, 35mm Pan
DreamCatcher Dobservatory, #2
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csa/montana
Astro Ambassador
Reged: 05/14/05
Posts: 26974
Loc: montana
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This post was made by member BillP. I believe it is the best explanation I've seen on the "Best Eyepiece(s)":
Quote:
Televue EPs are not the best. No single eyepiece or eyepiece line is the "best." What TV's are, is a premium-level eyepeice combining excellent optics with excellent build/fit/finish. In the same league with them are many others such as Pentax, Takahashi, and yes Questar/Brandon. IMO, once you get to the premium levels, for the most part (there are always exceptions) what you now have is all of them having excellent optics, and the differences are now subtle as each company does soemthing a little different, accenting a different aspect of the optical performance realm. This now translates into satisfying the tastes of a subset of people. So TVs are warmer in tone, Brandons cooler, there are subtle differences in levels of scatter and contrast and of course the afov. So all these things add up to being able to please collectively, most of the people out there after top-shelf optics.
So bottom line is that there are several "Best" eyepieces out there. Your own personal preferences and tastes really define which of the group becomes best for you.
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Carol
AstroTech 16" Dob (Thanks ASTRONOMICS!)
AstroTech 66ED / Vixen 80MF/AstroTech Voyager
Masuyama's 7.5, 15, 25W, 35mm,
Tak LE 5mm
7mm Pentax XL, 10mm Pentax XW
14mm Meade 4000 UWA
22mm Pan, 35mm Pan
DreamCatcher Dobservatory, #2
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