The NWJ-3 Internal Focusing telescope is designed for multi-purpose applications, such as aligning optical path, and self-collimation parallel light source.

Primary specifications:
1) Telescope objective
     Focal length: 208.34 mm
     Adjustable focal length range: 102 mm to 354.5 mm
     Field of view: +/-1.5°
     Aperture diameter: 25mm
     Angular Resolution: 5.6 arc seconds

2) Micrometer Eyepiece
     Focal length: 16.7mm
     Magnification: 15´
     Field of view: +/-18°
    Measurement accuracy: 6 arc seconds when used as self-collimation parallel light source
    Observational range: -317.14mm→∞ and +∞→420mm, outside blind
    Minimal scale of micrometer wheel: 0.01 mm, equivalent to an angle of 10 arc second of beam divergence at 208.34-mm focal length

3) Supporting mechanism
    Coarse range: angle of pitch is 7°, angle of pan is 45°, lift travel is 110 mm
    Fine range: angle of pitch is ±7°, angle of pan is ±7°, lift travel is 10 mm

4) Light source
    Incandescent lamp, 6V15W, or 6V30W, interchangeable