THE SCIENCE
What you are looking at
An illustrative, fictional two-axis alt-azimuth telescope mount: 146 separately selectable parts (tripod, azimuth bearing and worm drive, fork, altitude axis, optical tube, rack-and-pinion focuser, electronics). One axis turns about the vertical (azimuth, limited here to ±170°), the other about the horizontal (altitude, −5°…85°).
Worm reduction
A worm wheel gives output angle = worm angle / ratio. The demo uses illustrative ratios of 80:1 (azimuth) and 64:1 (altitude), so the motor shaft turns 80 or 64 times per output revolution. Worm drives are also self-locking at low lead angles, which is why they hold a telescope in place when power is off.
Alt-azimuth versus equatorial: field rotation
An alt-azimuth mount needs both axes to move to follow a star, and the sky image slowly rotates in the eyepiece or camera (field rotation) because the mount's axes do not line up with the Earth's rotation axis. The rotation rate is largest near the zenith and is corrected with a derotator or by short exposures. An equatorial mount avoids this by aligning one axis with the celestial pole.
Honest simplifications
This is a teaching illustration, not a manufacturing drawing. There is no optical ray tracing, no finite-element load analysis, no ephemeris-based sky tracking and no true tooth-contact dynamics. "Auto track" only sweeps the axes. The snap tolerance (0.33 m, 15°) is a deliberately broad interface tolerance, not an engineering fit. Masses and materials are estimates.
Illustrative design, not affiliated with any telescope manufacturer. Model files: assembled GLB · exploded GLB · parts JSON.