The Low Profile 1.25" Focuser for Newtonian, 3.5" Base, is a high-precision, pin-and-groove type helical focuser. The 3.5" base provides for replacing larger focusers with a center-to-center hole-spacing of 2.75". The draw-tube does not rotate.
Accessories that take up back-focus, such Lumicon's popular 1.25" Multiple Filter Selector, can be used with ease and convenience. The high-precision, smooth focusing brings out the very best in your telescope's optics. The low-profile design quickly and easily converts your standard Newtonian to a camera-ready telescope. The U-groove base aligns and sits flush on any telescope tube with a radius of 4.5" or larger.
- Focuser Minimum Height Above Tube* .75" (for 4.5" radius tube), 2" (for flat-base mounting)
- Turns Ratio: 2 per inch
- Travel: 1"
- Resolution/Backlash: < 0.0005"
- Image Shift: Negligible
- Reverse Action: Negligible
- "Stiction:" Negligible
- Footprint: 3.5" Square
- Mounting Hole Pattern: Square; 2.75" center-to-center
- Min/Max focuser hole diameter: 1.5"/3.3"
- Operating Range: to 20°F/- 7° C
- Maximum Recommended Load: 3 lbs
- Mounting Hardware: 8-32, Included
*Precise minimum depends on radius of tube.
Note: Visual use of the Low Profile Focuser requires either the Lumicon 1.25" Multiple Filter Selector, LF5010, or a 1.25" extension tube, such as the Lumicon LA1020.