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Starlight 3.5" Feather Touch Rack & Pinion Focuser with 4.5" DTT & Brake - FTF3545B-A

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SKU: SLI-FTF3545B-A

Starlight 3.5” Rack & Pinion Feather Touch Focuser
4.5” Draw Tube Travel & Brake
Choose Tube Adapter & End Cap Options Below

Everyone knows that the optics are the number one ingredient in any telescope, but the focuser is of comparative importance when it comes to the viewing or imaging experience. The focuser is the link between the telescope itself and the eyepiece or camera. If it is shaky or jumpy when the draw tube is racked in or out, or flexes when heavier eyepieces or accessories are introduced, your focuser can make observing almost impossible. A quality focuser should provide precise positioning of the eyepiece or camera to within .002 inches. Focusing should be smooth and easy, without any backlash, so that the telescope doesn’t vibrate or shake, even at higher magnifications. A decent focuser should be able to handle the weight of today’s multi-element eyepieces, as well as a DSLR or standard CCD camera.

Starlight Instruments Feather Touch focusers are one of the highest quality focusing mechanisms available to the amateur astronomer today. While they cost more than many focusers on the market, upgrading your stock focuser with a Starlight Feather Touch will be worth it, and with care, it should last a lifetime! You will enjoy a focuser that produces virtually zero backlash and provides a smooth, effortless focusing experience. Feather Touch focusers are designed to hold those big 2" eyepieces, or CCD camera/filter wheel imaging set-ups. They are strong and beautifully machined out of quality materials that are well suited to the rigors of astronomy.

The FTF3545B-A 3.5" Feather Touch Focuser is built to handle heavier loads, with a lifting capacity of 18 - 20 pounds! Graduated markings on the draw tube make it easy to find that "sweet spot" again and again. There is an internal brake built into the system to allow you to control the drag on draw tube movement. This focuser is so smooth, you may just have to put on the brake a little bit to keep the draw tube from gliding on its own! Luckily, the glide factor is easy to adjust with the integral brake.

Dual Speed 10:1 Fine Focus: Starlight Instruments is the original developer of the fine focus reduction unit, an assembly that allows for very accurate, fine focus at a 10:1 ratio. Course focus is achieved with the larger of the two focus knobs, and precise focus is accomplished by turning the smaller knob.

Internal Brake System: The focuser brake controls the “drag” on the draw tube, allowing the user to gradually increase the friction between the draw tube and the pinion. Adjusting the drag helps prevent any downward motion of the focuser caused by that pesky thing called gravity. The brake in this Starlight Feather Touch focuser consists of an internal leveraged leaf spring that is tightened with a thumbscrew. This thumbscrew is also used to lock the pinion shaft. Feather Touch focusers without the internal brake option use a thumbscrew alone to help control drag, which offers less range than the addition of a leveraged leaf spring.

This Feather Touch Focuser requires a tube adapter and an end cap, and they are sold separately. You can choose from the options above, or if you already have the proper adapters, you are welcome to choose "No Thanks". If you don't see the parts you need here, please contact us so we can put together the best focusing system for your needs.

Starlight 3.5” Feather Touch Focuser 3545B-A Specifications

  • Model Number: FTF3545B-A
  • Focuser Size: 3.5”
  • Draw Tube Travel (DTT): 4.5” or 114.30 mm
  • Thread on Visual Side Draw Tube: 4 3/32 x 24TPI
  • Lifting Capacity: 18-20 pounds
  • Reduction Ratio: 10:1
  • Draw Tube Drive Mechanism: Rack & Pinion
  • Internal Brake: Yes
  • Finderscope Hole Thread Dimension: 8-32
  • Racked In from Mounting Face: 5.236" with Compression Ring End Cap Option
  • Racked Out from Mounting Face: 9.736" with Compression Ring End Cap Option