This very high quality, dual-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 make achieving precise focus for visual observations and astrophotography a breeze and you will experience very smooth and precisely controlled focuser motion with zero backlash and zero image shift.
Focuser Specifications (With Curved Base Plate):
Minimum focuser height (with 1.25" adapter) = 3.27" (83mm)
Maximum focuser height (with 1.25" adapter) = 4.84" (123mm)
Minimum focuser height (without 1.25" adapter) = 2.87" (73mm)
Maximum focuser height (without 1.25" adapter) = 4.45" (113mm)
Tube travel = 1.57" (40mm)
Drawtube outer diameter (cut-out in your telescope tube must exceed this) = 2.29" (58.1mm)
Focuser weight (with 1.25" adapter) = 1lb-10.5oz (751gm)
Focus knob diameter = 1.57" (40mm)
Microfocuser knob diameter = 1.02" (26mm)
Microfocuser reduction ratio = 1:10
Maximum outer body 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
2" to 1.25" adaptor with compression ring and 2" filter thread