Feather Touch 2.5" Dia Dual Speed Focuser 3.5" DTT, Brake, with Integral 95mm x 1mm Teflon Coupled Collar
Our 2500 Series 2.5" Diameter Focusers
Two basic configurations are available for each size draw tube:
FTF25XXB-A "Standard Kit" which comes with our most popular 2.0" Compression Ring End Cap.
FTF25XXB - No End Cap.
Basic Componants of the Feather Touch 2.5 inch Diameter Focuser The 2.5" Feather Touch focuser is identical in design to its larger cousin, the 3.0". Both are closely related to our big daddy, the 3.5", and incorporate the same advanced features that are ideal for applications which demand precision imaging while also managing a heavier weight capacity than our 2.0" models.
- A factory-installed integrated Teflon-coupled collar provides a bind-free 360 degrees of smooth focuser rotation. Thumbscrews on the collar make detaching the focuser a snap as well.
- 95mm x 1mm male thread on the integrated collar allows attachment of tube adapters, bases, and other accessories.
- As with our other focusers, the 2500 series uses internally machined light baffles for superior light-reducing.
- Also standard is our internal brake.
- The draw tube's female 63mm x 1mmm thread allows total End Cap, Adapter and/or Optical Accessory configuration.
- The thumbscrew on the focuser makes rotating easy relative to the optical tube assembly.
The 2500 series focusers come with our Fine Focus Reduction Unit which allows very accurate focusing. It is typically a 9:1 planetary reduction assembly that makes focusing extremely precise and easy. We were the original developer of this type of system for telescope use and have been making and improving these for longer than any other manufacturer. These units have undergone continuous improvement and we believe they are, quite simply, the best in the industry.
The smooth and precise feel of our Fine Focus Reduction Unit is the key, and it allows our users to focus precisely with unparalleled accuracy, speed, and reliability.
Rack and pinion design using a precision fine pitch ½ inch wide Brass rack and matched hardened Stainless Steel pinion.
About our Internal Brake System...
Because the focuser is so smooth in operation and moves so freely, it can only hold a limited amount of weight (generally about 1 lb.) without drifting out of focus when the focuser drawtube is not horizontal and has a vertical component. The focuser therefore contains an adjustable tension internal brake system to allow astrophotography and visual use with heavy eyepieces without the possibility of the focus shift.
The brake consists of a lever arrangement internal to the pinion block. Adjusting the thumbscrew on the pinion block causes the lever to press a friction pad onto the pinion. This increases the torque needed to turn the focus knobs. If the thumbscrew is turned all the way in (only 1 to 1½ turns), the pinion shaft and the drawtube are locked in position for long exposure astrophotography.
Visually, partial tightening of the internal brake offers a virtually infinite range of braking force to accommodate various eyepiece weights. Moderate finger-pressure tightening of the drawtube tension screw allows the lifting capacity to be adjusted up to a nominal maximum of five pounds, although greater payloads are possible by further tightening the tension screw.