GSO Crayford Focuser for Reflectors - Single Speed

This very high quality, single-speed Crayford focuser for reflector telescopes from Guan Sheng Optical (GSO) is a joy to use. You will wonder how you ever lived without it once you install it!  It will greatly aid in achieving precise focus for visual observations and astrophotography and you will experience very smooth and precisely controlled focuser motion with zero backlash and zero image shift. 

CNC machined from aluminum and anodized black, this focuser comes with a base plate to attach to your reflector telescope.  The inner drawtube glides on 4 precision bearings and a roller shaft and provides 35mm of focus travel. The inner barrel is baffled and painted a flat black to minimize reflections for maximum contrast.

The 2" focuser barrel features a brass compression ring so your eyepieces and other accessories will not be marred by the set-screw. Also included is a 1.25"-2" adapter with brass compression rings that is threaded to accept standard 2" filters.

The focuser comes with a curved base plate (available in 8"/10" and 12" models) for mounting on many telescopes. Please make your size selection while ordering this item. Flat bases are also available at an additional charge. For help in deciding which base plate to choose (including specifications and hole spacing), please click here.


The focuser also has two large thumbscrews. The thumbscrew on the telescope side can be used to lock the focuser, allowing the use of heavy accessories or cameras without fear or slippage or losing focus. The other thumbscrew on the eyepiece end can be used to adjust the tension of the focuser to achieve a focusing "feel" that you like.  At the easiest (lightest) setting, the focuser moves extremely smoothly. At tighter settings, you can still use heavier accessories without sacrificing much of the smooth focuser action. GSO's rated load capacity for their Crayford focusers is a little less than 6 lbs (2.7 kgs).

Focuser Specifications (With 8"/10" Base Plate):
- Minimum focuser height (with 1.25" adapter) = 3.23" (82mm)
- Maximum focuser height (with 1.25" adapter) = 4.61" (117mm)
- Minimum focuser height (without 1.25" adapter) = 2.83" (72mm)
- Maximum focuser height (without 1.25" adapter) = 4.21" (107mm)
- Tube travel = 1.38" (35mm)
- Focuser weight (with 1.25" adapter) = 1lb-6.7oz (643gm)
- Focus knob diameter = 1.57" (40mm)
- Microfocus knob diameter = N/A
- Maximum outer barrel diameter = 3.15" (80mm)
- Millimeter markings on focuser drawtube: No
- Rotatable: No (But body can be rotated by loosening two allen screws that connect the focuser to the base plate)
- Dust plug: One 1.25" dust plug included

Description copyright: Agena AstroProducts (2008). Reproduction without permission prohibited.