Orion 8" F/3.9 Newtonian Astrograph

ITEM #
OR-08297
  • Aperture: 8"
  • Focal Ratio: f/3.9
  • Focal Length: 800mm
  • Excellent Value Newtonian Reflector
  • Sale
  • Regular price $499.99

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Orion 8" F/3.9 Newtonian Astrograph

Orion's 8" aperture deep-sky imaging specialist boasts features usually reserved for much pricier astrophotography telescopes. In fact, the Orion 8" f/3.9 Newtonian Astrograph's powerful imaging performance easily exceeds what's achievable with many premium apo refractors costing thousands of dollars more.

Orion Astrograph Optical System

Its 8" parabolic primary mirror has 800mm of focal length, making the fast f/3.9 Newtonian an ideal wide-field astrophotography telescope. A substantial 70mm minor axis secondary mirror provides full field illumination to CCD and/or DSLR cameras for efficient astrophotography performance. This provides less than 10% light drop-off around the corners of very large APS-C sized sensors. Both primary and secondary mirrors boast enhanced reflectivity (94%) aluminum coatings with a protective silicon dioxide (quartz) overcoat. Three easy-grip, push-pull collimation hand knobs on the primary cell make collimation adjustments easy. Once aligned, three locking thumbscrews secure the 8" parabolic mirror.

Images acquired with the 8" f/3.9 Newtonian Astrograph will exhibit maximum contrast thanks to sophisticated telescope features any astrophotographer will appreciate. Nine precisely positioned baffle rings along the inside of the reflector optical tube minimize internal reflections of pesky off-axis light for pristine imaging performance. To further optimize contrast and avoid off-axis light intrusion near the front of the telescope, the dual-speed 2" Crayford focuser has been installed a full 6.3" back from the front of the 30" long reflector optical tube. What's more, the entire inside of the rigid, rolled steel optical tube is coated with high-quality flat black paint to ensure high contrast.

Low-Profile, Smooth Focus

The reflector telescope's low-profile Crayford-style focuser has a full 69mm of backfocus, making it ideal for use with multiple imaging accessories. The smooth-adjusting focuser is held rigidly in place without any possibility of flexure thanks to a sturdy internal steel reinforcing plate. With fine focus adjustment capabilities at a ratio of 11:1, the smooth focuser is a joy to use and makes it easy to perform minute focus adjustments. Drawtube tension is adjustable, so you can customize focuser tension according to the load of astrophotography accessories being used.

As with any fast Newtonian reflector telescope, an optional coma corrector is recommended to eliminate inherent coma for optimized imaging performance. When used with a coma-corrector, the 8" Newtonian Astrograph will astound you with the amount of depth and resolution seen in astrophotos with round stars all the way out to the edges of the substantial field of view.

The Orion Visual Experience

The 8" Newtonian Astrograph can also be used for spectacular visual observations of deep-sky and solar system based celestial objects. The reflector's 8" aperture and fast focal ratio will amaze you with high-contrast views of the cosmos. Handy extension adapters are included for optimal use of 2" and 1.25" telescope eyepieces.

A thorough complement of accessories comes with the 8" f/3.9 Newtonian Astrograph telescope. Standard accessories include a cooling accelerator fan for speedy temperature equilibration, a pair of cast aluminum tube rings equipped with both upper and lower 1/4"-20 mounting holes, quick collimation cap, and a 9x50 finder scope. Eight AA batteries (not included) are required for cooling accelerator fan operation, or a portable 12V power supply (sold separately) can be used.

With a weight of just 17.5 lbs. by itself, and 21.8 lbs. with the included accessories installed, the Orion 8" f/3.9 Newtonian Astrograph can be supported easily by most equatorial mounts designed for astrophotography use.

Manufacturer Product Number: 08297

SPECIFICATIONS

Alignment ProcedureManual Alignment
Aperture203 mm (8")
Focal Length800 mm
Focal Ratiof/3.9
Focuser Size2"
Focusing SpeedsTwo Speed
Highest Useful Magnification300x
Limiting Stellar Magnitude14.2
ManufacturerOrion
Optical DesignNewtonian
Tube Length762mm
Tube Weight17.5 lbs