Review: 8" Orion SkyView Pro 8 OTA

Specifications:
Manufacturer: Orion Telescopes & Binoculars
Supplier: Orion Telescopes & Binoculars (800) 447-1001
List Price / Street Price: $269/$269 (OTA only)
Configuration: Newtonian Reflector
Aperture 203mm (8 in.)
Focal length: 1000mm
Focal Ratio: 4.9
Focuser 2", with 1.25" adapter
Weight: 16.5 lbs

Findings and recommendation: This tube is made with the strength and precision for some serious work. Highly recommended - though buy the whole unit, with Orion mount, instead of trying to save money like we did.

We were pleasantly surprised with the final result of our budget 8" telescope project. As seen here, we began with a generic Chinese reflector telescope with heavy-duty eq mount. As that optical tube contained defects in design, and could not be fixed under budget, we opted instead to replace that OTA with an assembly from Orion Telescopes. We were able to subsequently unload the flawed OTA for $100. Therefore, we were able to achieve our final goal of a quality 8" equatorial telescope for less than $500.

The Chinese mount, after repairs, was retained, despite having to support approximately eight more pounds than originally intended. Balance was "almost" achieved with the two supplied weights from the Chinese scope mount. About 1-2 more pounds of counterweight will have to be added to achieve perfect balance with the accessory finder mounted. Also note the ring retainer bolts. They are temporary. The ones supplied on the original mount were too short to accomodate the additional diameter of the Orion tube.

Optical tube findings:
Quality assessment: Very good to excellent. Plastic usage was kept to a minimum. The focuser is higher in quality, and smoother to operate, than any sub-$2,000 offering from the Big Two. The spider is four-vaned, and resisted more than 8 lbs of torque before beginning to twist. The mirror cell is especially well-designed. It exposes most of the back of the mirror to cool air, and even has a provision to mount a fan, for astronomers in a *hurry* to acclimatate.

Collimation procedure:
A short focal length tube ALWAYS has to be collimated. We used the laser collimator from Orion to check and align. The laser is a great tool for tubes known to be in general alignment. A check can be performed in less than one minute, and collimation performed in 2-3 minutes. Orion thoughtfully spots the main mirror at the factory.

The tube arrived from Orion in collimation. The red dot, reflected back to the collimator, was approx. 5 mm from center. The alignment limit was achieved with a half turn on one of the standard collimation screws.

Initial viewing test:
The initial viewing test was very positive. After a half-hour cooldown, Jupiter was viewed in steady, but badly light-polluted skies, about 45 degrees above the horizon, using a generic 6.3mm Plossl eyepiece that was supplied with the Helios Explorer. Four bands were immediately apparent. A quick Airy disk test on a nearby star was round. Pinpoint objects revealed no fringing or coma. Cassini was immediately apparent on Saturn (at zenith) in a cloud of moons, down to Rhea.

M42 viewed at 40 power revealed a pinpoint Trapezium and color in the nebula. All in all much more than we expected in a tube at that price.

Long term update: (added 07 JUL 2003)
After six months of continuous usage, no problems are noted.

Long term update: (added 05 JUL 2004)
After eighteen months of continuous usage, no problems are noted in the OTA. The (non-Orion) Helios mount develops occasional looseness and requires adjustment (typically, tightening the RA and Dec controls) prior to most viewing sessions.