Baader 3" RT Steeltrack Crayford Focuser for Refractors # FOC-RT3 2957110

In recent years the Crayford style of ball-bearing guided focuser has become popular due to its smooth motions, absence of pinion backlash, and rigid drawtube support. Baader's new Steeltrack Premium Focusers incorporate a number of innovative features that further enhance the smoothness and robustness of the Crayford focuser. Steetrack focusers are available to fit practically every telescope, from Refractors to Newtonians, and SCTs.

All Baader Steeltrack focusers incorporate the following features:

• The precision ball bearings ride on hardened and polished stainless steel ways that are inset into the thick-walled aluminum drawtube. The large diameter pinion drive also rides on a precision laser cut hardened and polished steel way. This important feature delivers an ultra-smooth motion that is superior to to the rougher motions of an aluminum bearing system, and guarantees that the buttery-smooth motions will remain that way over the life of the focuser. Crayford focusers that rely on machined and anodized aluminum bearing ways can become worn and pitted with use, which results in loss of smoothness and accuracy.
  
  
• The extra-large focusing knobs and Precision 1:10 reduction gearing permits ultra-fine motion control without backlash.
  
  
• Precision Pinion Drive and Bearing Assembly delivers an exceedingly smooth slipless motion and avoids the drawtube flexure present in other crayford focusers.
  
  
• Each Steeltrack incorporates a drawtube locking screw that supports even extremely heavy cameras and eyepieces without flexure or slippage. The knurled lock screw incorporates a swivelling anti-marring brass insert that allows firm clamping of the drawtube without marring or damage to the focusing mechanism.
  
  
• Internal drawtube surfaces are knife-edge baffled to eliminate stray light reflections.
  
  
• Bronze compression rings permit secure clamping of eyepieces and accessories without marring.
  
  
• Baader Precision and Quality. All parts are precisely machined and their high surface quality make the Baader Steeltrack an attractive complement to any telescope.
  
  
• Graduated markings on the drawtube aid in measuring and repeating focus positions.
  
  
• A complete set of adapters and extensions permit adaptation onto practically any telescope.
  
  

Baader Planetarium's Giant 3" Refractor Steeltrack Focuser gives large refractor owners the same ultra-smooth focusing and robustness as their 2" focusers, but in an oversized 3" format.  There is no smoother and finer made large format focuser on the planet.

• Overall length fully retracted 88mm (backfocus length), measured to face of 2" Eyepiece Holder.
  
  
• Focuser Travel of 115mm.
  
  
• Drawtube ID of 3" (76mm), OD 3.4" (87mm).  Fully internally baffled and blackened to eliminate off-axis stray light.  Threaded Internal M82. 
  
  
• Includes Baader M82/M68 Reducer Ring for attachment of 2" Eyepiece Holder and M68 Extension Tubes.
  
  
• Includes Deluxe 2" Eyepiece Holder, with internal Bronze compression ring and dual lock screws. Optical Path Length 12mm.  Also has M68 external thread for attachment of Baader M68 accessories.
  
  
• 4" dovetail receiver permits 360degree rotation of focuser with single-screw locking.
  
  
• Optional adapters and spacers permit easy attachment to large refractors.
  
  
• Focuser Weight: 3lb 13oz (1740gm)
  
  

Additional Agena Notes:

1) The ID of this focuser's body is 102mm and OD is 116.6mm. Directly, this focuser can only slip over telescope tubes that are 102mm or slightly smaller in diameter.

2) The OD of the drawtube is 87mm. Any telescope tube you attach this focuser to must have an internal opening at least this large to allow the drawtube to pass through.

3) Baader sells optional AD100a and AD116a adapters. These can be attached to this focuser to enable it to be connected with several brands of telescopes. The following combinations are possible:

(i) RT3 Focuser + AD100a Adapter = Focuser body converts to a male M100 thread or Xmm slip-fit flange on the telescope end
(ii) RT3 Focuser + AD116a Adapter = Focuser body converts to a female M116 thread on the telescope end