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Dual-Speed 2-inch Crayford Focuser for SCT Telescopes

Dual-Speed 2-inch Crayford Focuser for SCT Telescopes
Ask About Stock
Dual-Speed 2-inch Crayford Focuser for SCT Telescopes
£175.00
Ex Tax: £145.83
  • Stock: Ask About Stock
  • Model: 20172
  • Shipping Weight: 1.30kg
  • SKU: 20172
  • GTIN: 5055534800157
  • MPN: 20172
  • Location: F1B3

DUAL-SPEED 2" CRAYFORD FOCUSER FOR SCT (SCHMIDT-CASSEGRAIN) TELESCOPES FROM OVL (Optical Vision Ltd, the official Skywatcher distributor in the UK and Western Europe).
 

A high quality CNC Machined 10:1 dual-speed Crayford focuser designed as an upgrade to Schmidt Cassegrain Telescopes.
Will accept both 1.25" and 2" standard format eyepieces. Provides an exceptionally smooth focusing operation with the utmost precision, with the aid of its fine-focusing facility. Features indexed drawtube.

Specifications of the 2-inch dual speed crayford focuser for SCT from Skywatcher
Outer diameter (silver bottom part): 90mm
Outer diameter (black part above silver part): 84mm
 

This focuser is not compatible with the 20929 Skywatcher motor focuser.

 

USAGE EXAMPLE:

1. Celestron C9.25 Edge HD with ZWO ASI294MC-PRO camera.

The back focus for the C925 Edge is 146mm, the focuser # 20172 takes up at least 90mm, leaving about 56mm or less for the rest, assuming that you do not use the 2" to 1.25" adapter that comes with the focuser.
So you can have the camera (6.5mm), then ZWO Filter Drawer (21mm) and then ZWO OAG (16.5mm), then attach a M48M4837 extension that serves as a 2" nosepiece, that's how you attach it to this Skywatcher focuser, model # 20172.
All the above adds up to 44mm, which leaves you 11-12mm movement for the focuser drawtube, so you don't have to be at the very edge of the focuser to be in the correct position.
Adding a Celestron Reducer will not change the validity of the above setup as the back focus stays the same from the outer edge (on the camera side) of the reducer.

 

 ADJUSTING THE FOCUSER

According to some user feedback, the following notes might be helpful if your focuser is not performing perfectly and needs adjusting...


1st: try this:
 
To adjust the rotation friction, there are three recessed set screws around the perimeter.
 
The friction of the focuser can be adjusted by turning the recessed Allen screw located in the centre between the focusing knobs.
 
2nd: if the above provided only partial results, check out the PDF instruction

This attached instruction is for a different, but similarly constructed focuser so might help too:
 
https://teleskop-austria.at/information/ARCHIV/sbau-micro10-la/pdf/Crayford_adjustment_SW120ED.pdf





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