Starlight Instruments Feather Touch 3.5" R&P Focuser

Helical Rack & Pinion Drive: A Certified 18-20 Pound Capacity

Designed specifically for heavy instrument packages, this focuser's helical rack and pinion drive provides a certified lifting capacity of 18-20 pounds. Unlike Crayford designs that can slip under heavy loads, the geared mechanism ensures your large-format camera, filter wheel, and off-axis guider remain perfectly stationary at any orientation. The construction from hardened stainless steel and aluminum guarantees rigidity, preventing tilt and flexure that can ruin long exposures.

10:1 Dual-Speed Reduction: Precision Control Without Image Shift

Achieving critical focus is non-negotiable for high-resolution imaging. The Feather Touch focuser employs a celebrated 10:1 planetary reduction assembly, allowing for exceptionally fine adjustments with zero backlash. The millimeter scale on the draw tube provides a reliable reference for repeatable focus positions between sessions or filters. This level of control lets you snap stars to perfect points without the coarse jumps or image movement common in lesser focusers.

360° Locking Collar: Frame Your Target Without Compromise

The integrated 360-degree locking collar is an essential feature for imagers. It allows you to rotate your entire imaging train to perfectly frame your target—from the faint spiral arms of the Andromeda Galaxy (M31) to complex mosaics of the Cygnus Loop—without having to physically rotate the camera in its adapter. Once your composition is set, the collar locks down securely, maintaining perfect alignment. Furthermore, the end cap provides collimation adjustment via three set screws, ensuring your optical train is perfectly orthogonal to the focal plane.

Engineered for Large Scopes: 1.375" and 4.5" Travel Options

This focuser is available with either 1.375 inches or 4.5 inches of draw tube travel to accommodate a wide range of optical configurations on large RC and Dobsonian scopes. The shorter travel is ideal for systems with minimal back-focus requirements, while the longer travel provides flexibility for complex imaging trains. This modularity, combined with a selection of custom tube adapters and end caps (sold separately), ensures a perfect, rigid connection to your specific telescope.

Feather Touch 3.5" vs. Stock Focusers: The Imaging Upgrade

For owners of large Ritchey-Chrétien or Dobsonian telescopes, upgrading from a stock focuser to the Feather Touch 3.5" is one of the most significant improvements you can make for astrophotography. It directly addresses the two most common points of failure in factory-standard focusers.

• Eliminates Mirror Shift: On SCTs and RCs, the Feather Touch replaces the imprecise mirror-moving mechanism, providing a fixed, external draw tube that completely eliminates image shift during focusing.
• Prevents Flexure and Slippage: Compared to stock Crayford focusers on Dobsonians, the 18-20 pound capacity and rack and pinion drive of the Feather Touch prevent the draw tube from sagging or slipping under the weight of a heavy camera and accessories.