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ozzy9039
sage
Reged: 11/12/07
Posts: 225
Loc: Tampa,, Fl.
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So has anyone noticed that in the middle of the book (when it describes how to figure the mag of eyepieces) it states that the ETX60 has a 400mm FL, but in the back in the specs section it says 350mm... hmmm which is it?
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"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction."
---Albert Einstein---
http://www.wix.com/ozzy9039/The-Ozvatory
-Orion XT8i-
-Orion 80ST (On CG4 EQ)
-Home Made 60mm Refractor (In The Works)
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DNTash
scholastic sledgehammer
Reged: 09/02/07
Posts: 762
Loc: India
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375mm?
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AT 72
TMB 92
Orion 120ST
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nytecam
Postmaster
Reged: 08/20/05
Posts: 5750
Loc: London UK
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Quote:
375mm?
my ETX-70 f/5 = 350mm fl so 375mm fl for '60' seems too 'long' 
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Nytecam 51N 0.1W
Meade 30cm LX200+ETX-70+e-finder+C8+Ha+CaK PSTs SBIG SGS+homebuilt spectrographs
Starlight SXVF_M9+Lodestar CCDs/Canon 300D DSLR/Fuji E550
My observatory build-ETX-70 imaging-my videos
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timlilley
member
Reged: 01/06/08
Posts: 21
Loc: Northeast Georgia, USA
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Quote:
ETX-60AT/ETX-70AT Specifications
Optical design ................................................................Achromatic Refractor
Clear aperture
ETX-60AT ..............................................................60mm (2.36”)
ETX-70AT ..............................................................70mm (2.76”)
Focal length ....................................................................350mm
Focal ratio (photographic speed)
ETX-60AT ..............................................................f/5.8
ETX-70AT ..............................................................f/5
Near focus (approx.)
ETX-60AT ..............................................................15 ft. (4.6m)
ETX-70AT ..............................................................17 ft. (5.2m)
Resolving power
ETX-60AT ..............................................................1.9 arc secs
ETX-70AT ..............................................................1.6 arc secs
Multi-coatings on objective lens ....................................Standard
Limiting visual stellar magnitude (approx.)
ETX-60AT ..............................................................11.2
ETX-70AT ..............................................................11.5
Image scale
ETX-60AT ..............................................................4.1°/inch
ETX-70AT ..............................................................4.1°/inch
Maximum practical visual power
ETX-60AT ..............................................................200X
ETX-70AT ..............................................................240X
That's from the ETX 60 owner's manual posted for download on the Meade Web site.
Quote:
The power, or magnification of a telescope is determined by the focal length of the telescope
and the focal length of the eyepiece being used. To calculate eyepiece power, divide the telescope's
focal length by the eyepiece's focal length. E.g., a 25mm eyepiece is used with the
ETX-60AT. The focal length of the ETX-60AT is 350mm (see "SPECIFICATIONS," page 29).
That's from page 10 of the same manual. I hope this helps.
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Clear Skies, Tim
Celestron C4R
William Optics ZS66
Meade ETX 80BB
Celestron/Vixen Cometron 60mm
Hyperion Zoom and 5mm
Celestron & Meade Plossls
Nikon D80 for imaging
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