Nanjing AMADA Instrument Co., Ltd. · Nanjing, China [email protected] · +86-15195807515
AMADA Microscopes Request A Quote
Home Products Biological MicroscopeZoom Stereo MicroscopeFluorescence MicroscopeMetallurgical MicroscopePolarizing MicroscopeVideo Digital MicroscopeMicroscope CameraAstronomy AccessoryMicroscope AccessoryMagnifier Knowledge About Contact Request A Quote
Home / Products / Astronomy Focuser / 1.25-inch Double Focusing Base M42 for A
1.25-inch Double Focusing Base M42 for Astronomical Telescopes

1.25-inch Double Focusing Base M42 for Astronomical Telescopes

The 1.25-inch Double Focusing Base M42 is a high-precision metal focuser for astronomical telescopes, designed for stable linear movement during focusing. It features dual M42 threads and a 10mm stroke with 0.05mm adjustment accuracy, ensuring no rotation of the eyepiece or mirror during focus. Ideal for guide mirrors, finder scopes, and zenith mirrors in observational astronomy and astrophotography.

  • Double helix mechanism ensures linear movement without rotation of inserted components
  • 0.05mm adjustment accuracy for precise focusing at high magnifications
  • All-metal construction provides durability and long-term stability
  • 10mm stroke with M42x0.75 top and bottom threads for compatibility with guide and finder mirrors
  • Compact design with minimum height 46mm and maximum height 56mm
Request A Quote +86-15195807515

Technical features

  • High-precision double helix focuser for guide mirror/finder mirror interface
  • All-metal construction ensures strength and long-term performance
  • Top external thread M42x0.75, bottom external thread M42x0.75, bottom inner ring external thread M31x0.5
  • Inside diameter 1.25 inch (31.75 mm)
  • Stroke length 10 mm
  • Adjustment accuracy 0.05 mm
  • Minimum height 46 mm, maximum height 56 mm
  • Linear movement only — no rotation of inserted components

Who it is for

  • Amateur and professional astronomers using refractors or reflectors
  • Manufacturers integrating focusers into telescope accessories
  • Distributors supplying precision components for astronomical equipment

Specifications

Model1.25-inch Double Focusing Base M42
Inside Diameter1.25 inch
Stroke10 mm
Adjustment Accuracy0.05 mm
Top External ThreadM42x0.75
Bottom External ThreadM42x0.75
Bottom Inner Ring ThreadM31x0.5
Minimum Height46 mm
Maximum Height56 mm
MaterialAll metal

Use guide

  • Install on telescope or accessory where linear focus without rotation is required
  • Ensure M42x0.75 threads match the mounting interface of the guide or finder scope
  • Use with CDD eyepieces or zenith mirrors to maintain alignment during focus

FAQ

Does the focuser rotate the eyepiece during adjustment?
No. The double helix design ensures only linear movement — no rotation of the inserted component.
What is the adjustment accuracy?
0.05 mm per full turn of the focusing knob.
Can it be used with a CDD eyepiece?
Yes. The 1.25-inch bore fits standard CDD eyepieces, and the design prevents rotation during focus.
What are the thread sizes?
Top: M42x0.75; Bottom: M42x0.75; Bottom inner ring: M31x0.5.
What is the maximum height?
56 mm when fully extended.

Related products