Beginning skywatchers looking for a low maintenance telescope that can serve up vivid, sharp images of the Moon, planets, and brighter deep-space objects need look no further than the Orion Observer 90mm Equatorial Refractor. A great telescope for the whole family, the Observer 90 EQ's fully antireflection coated 90mm-diameter (3.5") front lens boasts strong magnifying power. With the included 25mm and 10mm Plossl eyepieces you will view distant worlds in high-contrast detail at 36x and 90x! Jupiter's cloud bands are easily discerned, as are all four of its major moons. Saturn's rings, sharp and dazzling. And the lunar surface teems with craters and mountains in rugged relief.
While the Observer 90 EQ excels at lunar and planetary observing, it can also provide great views of many more-distant objects. At 36x the Orion Nebula exhibits the four Trapezium stars as perfect blue pinpoints surrounded by greenish gas. Pop in the 10mm eyepiece to boost the power to 90x and - wow! - The nebulosity spans nearly the entire eyepiece field of view! In the summer sky the Great Hercules Star Cluster (M13) starts to resolve into tiny stellar pinpoints.
The Observer 90 EQ features a 1.25" rack-and-pinion focuser for dialing in the sharpest view. A 90-degree star diagonal inserted in the focuser provides a comfortable viewing angle. The 6x30 crosshair finder scope helps you locate your targets.
The Observer's sturdy equatorial mount can be quickly polar-aligned to allow easy "tracking" of celestial objects as they move slowly across the sky, using just one of the two slow-motion knobs. Use both to center objects in the telescope's field of view. The extendable aluminum tripod provides solid support, and has an accessory tray to keep your extra eyepiece and Barlow within easy reach.
The telescope weighs under 17 lbs. total, including the easily removable counterweight, so it's easy to take outside for impromptu observing sessions.
- Best for viewing: Lunar & planetary
- User level: Beginner
- Optical design: Refractor
- Optical diameter: 90mm
- Focal length: 900mm
- Focal ratio: f/10.0
- Coatings: Fully coated
- Optics type: Air-spaced doublet
- Glass material: Crown/Flint
- Eyepieces: Plossl 25.0mm,10.0mm (1.25")
- Magnification with included eyepieces: 36x, 90x
- Resolving power: 1.29arc*sec
- Lowest useful magnification: 13x
- Highest useful magnification: 180x
- Highest theoretical magnification: 180x
- Limiting stellar magnitude: 12.5
- Optical quality: Diffraction limited
- Finder scope: 6x30
- Focuser: 1.25" Rack-and-pinion
- Diagonal degrees: 1.25" 90° Mirror Star
- Secondary mirror obstruction: 40mm
- Secondary mirror obstruction by diameter: 30%
- Secondary mirror obstruction by area: 22%
- Mirror coatings/over-coatings: Aluminum & Silicon Dioxide
- Mount type: Equatorial
- Dovetail bar system: Yes
- Motor drive compatibility: Clock drive sold separately
- Setting circles: Yes
- Polar-axis scope: Not available
- Counterweights: One 4 lb.
- Tube material: Aluminum
- Tripod material: Aluminum
- Counterweight bar length: 8 in.
- Diameter of counterweight shaft: 13mm
- Height range of mount: 37.50 in. - 69.50 in.
- Length of optical tube: 34.0 in.
- Weight, optical tube: 4.7 lbs.
- Weight, mount/tripod: 11.4 lbs.
- Weight, fully assembled: 16.1 lbs.
- Other features: Dual slow-motion cables, dovetail saddle for easy attach/detach of OTA, dew shield reduces off-axis glare and dew on lens