Telescope specifications – Meade Instruments ETX 90EC User Manual
Page 21
z
21
TELESCOPE SPECIFICATIONS
CHAPTER
6
Specifications: ETX-90EC Astro Telescope
Optical design . . . . . . . . . . . . . . . . . . . Maksutov-Cassegrain
Primary mirror diameter . . . . . . . . . . . . . . . . . . 96mm (3.78”)
Clear aperture . . . . . . . . . . . . . . . . . . . . . . . . . . 90mm (3.5”)
Focal length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1250mm
Focal ratio (photographic speed). . . . . . . . . . . . . . . . . . f/13.8
Near focus (approx) . . . . . . . . . . . . . . . . . . . . . 11.5 ft (3.5m)
Resolving power. . . . . . . . . . . . . . . . . . . . . . . . . 1.3 arc secs
Super multi-coatings (EMC). . . . . . . . . . . . . . . . . . . standard
Limiting visual stellar magnitude (approx.). . . . . . . . . . . . 11.7
Image scale. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.16°/inch
Maximum practical visual power . . . . . . . . . . . . . . . . . . 325X
Optical tube dimensions
(dia. x length) . . . . . . . . . . 10.4cm x 27.9cm (4.1” x 11”)
Eyepiece. . . . . . . . . . . . . . . . . . . . . . . . . Super Plössl 26mm
Viewfinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 x 21mm
Secondary mirror obstruction (dia.; %) . . 27.9mm (1.1”); 9.6%
Telescope mounting . . . . . . . . . . . . . . . fork type; double tine
Setting circle diameters . . . . . . . . . . . . . . . . Dec: 3.5”; RA: 7”
Input voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 volts DC
Motor DriveSystem DCservo motors
with encoders, both axes
Slow-Motion Controls . . . . . . . . . electric, 4 speed, both axes
Optional Autostar Capability. . . . . . . . . . . . . . . . . . . . . . . yes
Hemispheres of operation . . . . . North and South, switchable
Bearings:
Altitude. . . . . . . . . . . . . . . . . . . . . . UHMW polyethylene
Azimuth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PTFE
Materials:
Tube body . . . . . . . . . . . . . . . . . . . . . . . . . . . aluminum
Mounting . . . . . . high-impact ABS, aluminum-reinforced
Primary mirror . . . . . . . . . . . . . . . . . . . . . . Pyrex
®
glass
Correcting lens. . . . . . . . . . . BK7 optical glass, Grade-A
Telescope dimensions:
. . . . . . . . . . . . . . . . 38cm x 18cm x 22cm (15” x 7” x 9”)
Telescope net weight:
(incl. Electronic Controller & batteries) . . 3.5kg (7.8 lbs)
Telescope shipping weight. . . . . . . . . . . . . . . 5.8kg (12.8 lbs)
Battery Life (approx.):
with Electronic Controller . . . . . . . . . . . . . . . . . . . 45 hrs
with Autostar . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 hrs
Specifications: ETX-125EC Astro Telescope
Optical design . . . . . . . . . . . . . . . . . . . Maksutov-Cassegrain
Primary mirror diameter . . . . . . . . . . . . . . . . . 138mm (5.43”)
Clear aperture . . . . . . . . . . . . . . . . . . . . . . . . . 127mm (5.0”)
Focal length . . . . . . . . . . . . . . . . . . . . . . . . . 1900mm (74.8”)
Focal ratio (photographic speed) . . . . . . . . . . . . . . . . . . . f/15
Near focus (approx). . . . . . . . . . . . . . . . . . . . . . . 5.5m (18 ft)
Resolving power. . . . . . . . . . . . . . . . . . . . . . . . . 0.9 arc secs
Super multi-coatings (EMC). . . . . . . . . . . . . . . . . . . standard
Limiting visual stellar magnitude (approx.). . . . . . . . . . . . 12.5
Image scale. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.76°/inch
Maximum practical visual power . . . . . . . . . . . . . . . . . . 500X
Optical tube dimensions
(dia. x length) . . . . . . . . . 14.6cm x 36cm (5.75” x 14.2”)
Eyepiece. . . . . . . . . . . . . . . . . . . . . . . . . Super Plössl 26mm
Viewfinder. . . . . . . . . . . . . . . . . . . . . . . 8 x 25mm right-angle
Secondary mirror obstruction (dia.; %). . 39.4mm (1.6”); 9.6%
Telescope mounting . . . . . . . . . . . . . . . fork type; double tine
Setting circle diameters. . . . . . . . . . . . . . . . Dec: 4.3”; RA: 9”
Input voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 volts DC
Motor Drive System . . DCservo motors with encoders, both axes
Slow-Motion Controls . . . . . . . . . electric, 4 speed, both axes
Optional Autostar Capability. . . . . . . . . . . . . . . . . . . . . . . yes
Hemispheres of operation . . . . . North and South, switchable
Bearings:
Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acetal
Azimuth . . . . . . . . . . . . . . . . . . . . . . . radial ball bearing
Materials:
Tube body . . . . . . . . . . . . . . . . . . . . . . . . . . . aluminum
Mounting . . . . . . . . . . high-impact ABS, zinc-reinforced
Primary mirror . . . . . . . . . . . . . . . . . . . . . . Pyrex
®
glass
Correcting lens. . . . . . . . . . . BK7 optical glass, Grade-A
Telescope dimensions:
. . . . . . . . . . 48cm x 23cm x 27cm (19” x 8.9” x 10.8”)
Telescope net weight:
(incl. Electronic Controller & batteries) . . 7.9kg (17.4 lbs)
Telescope shipping weight. . . . . . . . . . . . . . 12.4kg (27.4 lbs)
Battery Life (approx.):
with Electronic Controller . . . . . . . . . . . . . . . . . . . 45 hrs
with Autostar . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 hrs