Astronomy Focuser

K001 1.25" Double-threaded Focuser for Astronomical Telescope

Name: K001 1.25" Double-threaded Focuser for Astronomical Telescope
Brand: AMADA Microscope

The K001 is a 1.25-inch double-threaded focuser made from all metal, designed for astronomical telescopes and telephoto lenses.

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K001 1.25" Double-threaded Focuser for Astronomical Telescope

Product Overview

The K001 is a 1.25-inch double-threaded focuser made from all metal, designed for astronomical telescopes and telephoto lenses. It provides a 10mm linear adjustment stroke with 0.05mm precision, ensuring smooth and stable focusing at high magnifications. The helical mechanism keeps inserted eyepieces or zenith mirrors non-rotating during focus adjustment, which is essential for consistent alignment in visual observation and astrophotography.

Inner diameter1.25"
Stroke10mm
Adjustment accuracy0.05mm
Top external threadM42x0.75
Bottom external threadM31x0.5
Minimum height43mm

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Key Benefits

10mm linear adjustment stroke allows fine focus control across a wide range
0.05mm adjustment accuracy enables precise focus at high magnifications
Non-rotating eyepiece or zenith mirror maintains alignment during focus
All-metal construction ensures durability and long-term stability
Compact design fits within tight telescope tube spaces, with a height range of 43mm to 53mm

Application Scenarios

Fine focusing during planetary or lunar observation with high-power eyepieces
Astrophotography setup where consistent alignment of the imaging train is critical
Mounting a guide scope or finder telescope with a stable, non-rotating interface
Adjusting focus on a telephoto lens used in astrophotography without rotating the lens
Replacing a worn or loose focuser on a telescope without changing the optical train

Who It Is For

Amateur and educational astronomy dealers setting up telescope systems
Research and teaching labs using telescopes for observational astronomy
Astrophotographers requiring stable, non-rotating focus for long-exposure imaging
Telescope builders and integrators assembling custom optical systems
Users of telephoto lenses adapted for astronomical use

Problems It Solves

A rotating eyepiece during focus adjustment disrupts alignment and requires re-centering
Low-precision focusers make it difficult to achieve sharp focus at high magnifications
Plastic or low-quality focusers wear out quickly under repeated use
Lack of a stable interface between guide scopes and main telescopes leads to misalignment
Inadequate stroke length limits the ability to focus across different eyepiece focal lengths

Technical Features

Double-threaded helical focuser with high-precision threading
Non-rotating insertion for eyepieces, zenith mirrors, or guide scopes
10mm linear adjustment stroke with 0.05mm resolution
All-metal construction for durability and thermal stability
Top external thread M42x0.75, bottom external thread M31x0.5 for secure mounting
Inner diameter 1.25 inch to fit standard eyepieces and accessories
Minimum height 43mm, maximum height 53mm for compact integration

Specifications

Inner diameter	1.25"
Stroke	10mm
Adjustment accuracy	0.05mm
Top external thread	M42x0.75
Bottom external thread	M31x0.5
Minimum height	43mm
Maximum height	53mm
Material	Aluminium alloy
Focuser type	Double-threaded helical
Adjustment method	Helical fine tuning
Rotation of inserted components	Non-rotating
Application	Astronomical telescope, telephoto lens

Specifications are taken from the AMADA product data for this item. Confirm critical dimensions with us in writing before ordering.

Customization Options

Available with or without additional mounting flanges for specific telescope models
Thread sizes can be adapted upon request for non-standard interfaces
Surface finish options available (anodized or bare metal) based on application

Comparison With Other Options

Single-threaded focuser	The double-threaded design offers twice the linear movement per rotation, enabling finer control and faster focusing adjustments.
Plastic focuser	The all-metal construction resists wear, maintains alignment under load, and performs reliably at high magnifications where plastic parts may deform.
Rotating focuser	This non-rotating design keeps the eyepiece or adapter fixed in orientation, which is essential for astrophotography and consistent visual alignment.

Use Guide

Ensure the telescope or lens is securely mounted before installing the focuser
Use the M42x0.75 top thread to attach the focuser to the telescope tube or adapter
Insert the eyepiece or zenith mirror into the 1.25-inch inner bore and tighten gently
Turn the focuser knob slowly to avoid overshooting focus; use the 0.05mm accuracy for fine adjustments
Check that the inserted component does not rotate during focus; if it does, verify thread engagement and alignment