ETX 90 AT UHTC
By Meade Telescopes

Pushbutton electronic control, combined with the finest optical systems ever made available in ultraportable telescopes.
When the original ETX® telescope, the ETX-90RA,
was introduced in 1996, it quickly created a revolution in
amateur astronomy. Here for the first time was a stunningly
beautiful, ultraportable, and highly versatile telescope
system of unprecedented optical resolution and
performance. Within one year of its introduction the ETX
became the largest-selling modern telescope in the world.
Meade ETX-90AT and ETX-125AT models build on the
original ETX concept to create the most advanced
electronically-controlled telescopes — including optional
automatic GO TO object-location with the Autostar™
Computer Controller — ever produced in their price
range. And yet without sacrificing any of the user-friendly
features that started the ETX revolution.
ETX-90AT Astro Telescope: For the casual or beginning
observer the Meade ETX-90AT may be all the telescope
ever required. Or, for the advanced astronomer who
already owns a larger instrument, the ETX-90AT is the
perfect ultraportable, diffraction-limited field telescope.
Observe the continually changing cloud-belt patterns on the
surface of the planet Jupiter; shadows cast on to Jupiter as
one of its four principal satellites transits the planet’s disc;
the magnificent ring system and satellites of Saturn as well
as dusky markings and the ring-shadow on the surface of
Saturn; Moon craters by the hundred, plus lunar rilles,
mountain ranges, and fault lines, all visible in brilliant, high-
resolution, high-contrast detail; the variable phases of the
planets Mercury and Venus; prominent features on the
surface of Mars. In deep-space the motivated observer will
find it difficult to exhaust the quantity of visible phenomena:
the incandescent filamentary structure of the Orion Nebula;
the elliptical luminosity of the Andromeda Galaxy with its
brilliant nucleus; the shining orb of the Hercules globular
cluster with many of its outermost stars resolvable. These
are only a few of the literally thousands of celestial objects
within the view of the Meade ETX-90AT telescope. Star
catalogs list innumerable double and multiple star systems,
variable stars, open star clusters, globular clusters, diffuse
nebulosities, planetary nebulae, and spiral galaxies within
the grasp of the instrument. The optional Autostar
Computer Controller can locate all of these objects
automatically, in seconds.
Optical Systems: Manufactured entirely at the Meade
Irvine, California, facility, ETX Maksutov-Cassegrain
telescopes produce optical performance and resolution that
equal or exceed any Maksutov optics of similar apertures
ever manufactured at any price, past or present. Optics so
high in contrast, image brightness, and resolution that the
ETX-90AT and ETX-125AT often outperform many
telescopes of larger apertures.
Fork Mounts with Standard-Equipment Dual-Axis Drive System and Electronic Controller: The fork mountings of
ETX-90AT and ETX-125AT models include high-torque DC motors on both telescope axes, permitting electronic operation from the standard-equipment plug-in hand controller. Use the pushbutton electronic controller at any of four dual-axis speeds: 8x sidereal for image centering in the main telescope at highpower; 32x for image centering at lower powers or for pushbutton object-tracking in the altazimuth mode; 0.75°/second for image centering in the viewfinder or for terrestrial tracking; 5°/second for fast slewing across the sky. The observer can instantly select any of these speeds simply by depressing the SPEED button on the controller.
Altazimuth or Equatorial Operation: With the telescope placed in the altazimuth mode on a table, astronomical object-tracking may be accomplished from the directional pushbuttons of the hand controller. Fully automatic astronomical tracking in the altazimuth mode may be accomplished with the optional Autostar Computer Controller. Alternately, the telescope may be mounted in the equatorial orientation, using either an optional Table Tripod or the Deluxe Field Tripod. In this latter case the telescope tracks celestial objects automatically at the sidereal rate.
Cordless Field Operation: The drive base of each telescope accepts eight (user-supplied) AA-batteries that power the telescope for more than 40 hours of normal usage, negating any requirement for an external power source in the field. Alternately, the telescope may be powered from an automobile cigarette lighter plug, using the optional #607 Power Cord.
Flip-Mirror System: Flip the internal, optical-flat mirror
“up” for observing in the standard 90° position; flip the mirror “down” for terrestrial observing with the optional #932 45° Erecting Prism or for photography with the optional #64 T-Adapter.
Materials and Coatings: ETX optical systems include a Maksutov meniscus corrector lens of Grade-A BK7 optical glass. This lens is individually hand-figured by a Meade master optician to achieve an optical null in combination with the Pyrex® primary mirror. Meade EMC super-multi-coatings on all optical surfaces maximize light transmission through the optical system.
Standard Equipment: Meade ETX Astro Telescopes are supplied as complete instruments. Standard equipment includes a premium-grade Meade Series 4000 Super Plössl 26mm eyepiece for 48X with the ETX-90AT or 73X with the ETX-125AT. The 8 x 21mm viewfinder of the ETX-90AT incorporates an internal roof prism that results in an erect- image orientation, facilitating the quick location and field- centering of both terrestrial and astronomical objects. The ETX-125AT is supplied with an 8 x 25mm right-angle viewfinder for comfortable object-sighting with the larger instrument.
Optional Accessories: Over 20 optionally available eyepieces permit a magnification range of from 31X
to over 300X with the ETX-90AT or from 48X to over 450X with the ETX-125AT. Meade Super Plössls are excellent eyepieces with either ETX model, or use a Meade Super
Wide 13.8mm, 18mm, or 24.5mm ocular for spectacular moderate-power, wide-angle observing. The #126 2x Barlow Lens, a special short-focus Barlow ideally suited to ETX systems, doubles the power of any eyepiece. For terrestrial photography or astrophotography of the Moon and planets, the #64 T-Adapter threads to either telescope’s rear cell and, with the appropriate T-mount, accepts any 35mm camera with removable lens.
Included Autostar Computer Controller: One of the most important advances in telescope design in the past 25 years, the Autostar Computer Controller brings to the amateur astronomer features heretofore available only on much more expensive telescopes. With Autostar plugged into your ETX, finding any of more than 14,000 celestial objects is as easy as pushing a button.
|
Specifications and Features: ETX
Astro Telescopes
|
| TELESCOPE: |
ETX-90AT |
ETX-90RA |
ETX-125AT |
|
| Optical
Design |
Maksutov-Cassegrain |
Maksutov-Cassegrain |
Maksutov-Cassegrain |
| Primary Mirror Diameter |
96mm (3.78") |
96mm (3.78") |
138mm (5.43") |
| Clear
Aperture |
90mm (3.5") |
90mm (3.5") |
127mm
(5.0") |
| Focal Length, Focal Ratio |
1250mm f/13.8 |
1250mm f/13.8 |
1900mm f/15 |
| Near
Focus (approx.) |
11.5 ft. (3.5m) |
11.5 ft. (3.5m) |
15 ft. (4.6m) |
| Resolving Power (arc
secs.) |
1.3 |
1.3 |
0.9 |
| Super
Multi-Coatings (EMC) |
Standard |
Standard |
Standard |
| Limiting Visual Stellar
Magnitude |
11.7 |
11.7 |
12.5 |
| Image
Scale |
1.16°/inch |
1.16°/inch |
0.76°/inch |
| Maximum Practical Visual
Power |
325X |
325X |
500X |
| Optical
Tube Dimensions (dia. x length) |
4.1"
x 11" (10.4cm x 27.9cm) |
4.1"
x 11" (10.4cm x 27.9cm) |
5.75"
x 14.2" (14.6cm x 36cm) |
| Eyepiece
|
Super Plössl 26mm |
Super Plössl 26mm |
Super Plössl 26mm |
| Secondary
Mirror Obstruction (dia.; %) |
1.1"
(27.9mm); 9.6% |
1.1"
(27.9mm); 9.6% |
1.55"
(39.4mm); 9.6% |
| Telescope Mounting |
Fork type; double tine |
Fork type; double tine |
Fork type; double tine |
| Setting
Circle Diameters |
Dec.:
3.5"; R.A.: 7" |
Dec.:
3.5"; R.A.: 7" |
Dec.:
4.3"; R.A.: 9" |
| Motor Drive
System |
DC servo motors with encoders,
both axes; 12-volts |
DC motor in R.A.
only; 4.5-volts |
DC servo motors with encoders,
both axes;12-volts |
| Slow-Motion
Controls |
Electric,
4-speed, both axes |
Manual,
both axes |
Electric,
4-speed, both axes |
| Optional Autostar
Capability |
Yes |
No |
Yes |
| Hemispheres
of Operation |
North
and South |
North
and South |
North
and South |
| Batteries
|
8 x AA |
3 x AA |
8 x AA |
| Battery
Life (approx.) |
|
50
hrs. |
|
| with
Electronic Controller |
45 hrs. |
|
45 hrs. |
|
with Autostar (optional) |
20
hrs. |
|
20
hrs. |
| Bearings
|
Nylon, both axes |
Nylon, both axes |
Dec: Nylon; R.A.: ball bearings |
| Materials:
Tube body |
Aluminum |
Aluminum |
Aluminum |
|
Mounting |
Reinforced high-impact ABS |
Reinforced high-impact ABS |
Reinforced high-impact ABS |
|
Primary Mirror |
Pyrex®
glass |
Pyrex®
glass |
Pyrex®
glass |
|
Correcting Lens |
BK7 optical glass, Grade-A |
BK7 optical glass, Grade-A |
BK7 optical glass, Grade-A |
| Telescope
Dimensions |
15"
x 7.3" x 8.5" |
15"
x 7.3" x 8.5" |
19"
x 8.9" x 10.8" |
| Telescope Net Weight |
9.2 lbs (4.2 kg) |
9.2 lbs. (4.2 kg) |
18.8 lbs. (8.5 kg) |
| Telescope
Shipping Weight |
12.4
lbs (5.6 kg) |
12.4
lbs (5.6 kg) |
23.7
lbs. (10.8 kg) |
|