ETX SPECIFICATIONS Last updated: 26 April 1997

Optical design.........................................Maksutov-Cassegrain
Clear aperture.................................................90mm (3.5")
Focal length................................................1250mm (48.6")
Focal ratio (photographic speed)....................................f/13.8
Near focus....................................................3.5m (11.5')
Resolving power...............................................1.3 arc secs
Super Multi-coatings..............................................standard
Limiting visual stellar magnitude.....................................11.7
Maximum practical visual power........................................325x
Optical tube dimensions.............10.4cm dia. x 27.9cm long (4.1" x 11")
Secondary mirror obstruction...........................27.9mm (1.1"); 9.6%
Telescope mounting..................................fork type; double tine
RA drive motor................................................4.5-volts DC
Hemispheres of operation.......................north and south; switchable
Slow-motion controls..................................manual; R.A. and Dec
Bearings...............................................R.A. and Dec: Nylon
Materials:
         Tube body................................................aluminum
         Mounting........................high-impact ABS, steel reinforced
         Primary mirror......................................Pyrex® glass
         Correcting lens........................BK7 optical glass, Grade-A
Telescope dimensions...................38cm x 18cm x 22 cm (15" x 7" x 9")
Telescope (incl. tripod) net weight........................4.2kg (9.2 lbs)
Telescope shipping weight.................................5.6kg (12.4 lbs)

Source: ETX User Manual

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