Feather Touch 10:1 Ratio dual speed manual focuser with brake - pre-2005 TeleVue

This Starlight Instruments Feather Touch micro-pinion assembly is a precision-machined dual-speed focuser upgrade designed to be installed on virtually all older (pre-2005) TeleVue refractors having a silver focuser drawtube. The Feather Touch improves the visual and photographic performance of your telescope's fine optics by converting the acceptable, but somewhat coarse, single-speed TeleVue rack and pinion focuser to the ultra-precision dual-speed focusing pioneered by Starlight Instruments. Starlight has been producing and perfecting the fine focus mechanisms in their Feather Touch reflector and SCT focusers for 15 years and has a well-deserved reputation for producing focusers of unparalleled precision and quality. This new TeleVue focuser extends Feather Touch precision to TeleVue refractors.

The FT-TV uses the existing TeleVue rack that is mounted on the silver focuser drawtube, but replaces the TeleVue single-speed pinion gear and knobs with a 10:1 ratio dual-speed fine focus mechanism that has ultra-smooth coarse/fine focus knobs. Ten turns of the fine focus knob equals one turn of the coarse focus knob, for ten times the focusing precision of the standard TeleVue focuser. The two large anodized aluminum coarse focus knobs have a knurled rim for superior feel and gripping action. The single concentric anodized aluminum fine focus knob has a smooth inertial feel and is also knurled for a sure grip, even when wearing gloves in cold weather. The reduction assembly is precision-machined from hardened stainless steel for improved reliability and toughness (rather than the softer and wear-prone aluminum gearing used on lesser focusers). An ultra-low backlash system provides accurate control. The laser-engraved black anodized aluminum pinion housing is sleek and precisely machined, with no sharp corners or edges to snag clothing.

All materials are the best available and no short cuts in design or fabrication are ever taken. Anodized aluminum is used for corrosion protection in the 15 ounce body and knobs. All high load parts are made from hardened stainless steel for long life, reliability, and toughness. This steel-on-steel running gear design will virtually never wear out or degrade with age or use. The focuser is easy to install and adjustable for reliable and optimum performance.

Because the focuser is so smooth in operation and moves so freely, it can only hold a limited amount of weight (generally a little more than 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, or visual use with heavy eyepieces, without the possibility of 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 (about 1 to 1¼ 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.