Spectra Precision Focus 30 Service Manual

Chapter 3
Theory of Operation
Focus 30/35 Service Manual 3 - 8 P/N 79000035_SM, Version 1.5
The module consists of Tracker servo focus board, motor and mechanics/optics.
A special spindle housing catchs abrasio and grease.
Fig. 3-6 Servo focus unit
The servo focus drive uses a eccentric stepper motor in micro steps mode for silent movement of the
focusing lens forward and backwards in the telescope. The mechanical part of the focus drive is
guided by a V-shaped notch so that the focusing lens travels exactly along the optical axis of the
telescope.
The manual focusing is operated by the focus-knob on the servo side cover. The instrument manager
on the MCB board processes the focus knob movement and sends it to the Tracker servo focus board.
The servo focus motor is controlled by the Tracker servo focus board.
During start-up routine the light barrier detects the position of the focusing lens.
The light barrier controls the position of both breakers and protects the servo focus unit against
accidental overrun.
Eyepiece
Shifting lens
Focusing drive
Focusing servo motor
Frontlens
Tracker servo
board
Light barrier
1,5m position
Infinite position

Spectra Precision Focus 30 Specifications

General

Brand	Spectra Precision
Model	Focus 30
Category	Measuring Instruments
Language	English