Computerized EQ-Mount

A multi-axial tracking device allowing the capture of long-exposure astrophotography.

Images taken with the mount.
How I built the mount.
EQ-Mount SolidWorks Visualize RenderSOLIDWORKS Visualize render.

See how each aspect of the mount was fabricated, step-by-step.

GoTo Capable

A central STM32 controller flashed with OnStep Firmware enables plate-solving and automatic framing of celestial objects.

Autoguiding minimizes periodic error by interfacing with OnStep via an ST4 port or directly through pulse guiding.

by Howard Dutton

High Resolution

Micro-stepping with a 360:1 worm gear ratio combined with a 3:1 reduction ratio allows slow, accurate tracking of the night sky.

The higher the gear ratio, the more continuous the mount's movement appears.

Fabricating accurate worm gears using a CNC mill and lathe.

Stable

A rigid 0.5" aluminum and alloy steel design minimizes vibration, contributing to tracking accuracy.

Sturdy twin-row angular contact bearings are used to transfer rotation along the mount's RA and DEC axes.

Machining aluminum parts and steel shafts using a CNC router, mill, and lathe.

How it works

Gathering enough light to observe deep-sky objects like nebulae and galaxies requires several long-exposure photographs carefully layered on top of one another. Unfortunately, an observer on the ground faces a dilemma: the Earth rotates.

In order to counteract the Earth's rotation, the telescope mount itself has to rotate at a sidereal rate, effectively following the night sky. This is done by first aligning the mount's right ascension axis with the celestial pole using altitude and azimuth controls. From there, the right ascension and declination axes can be altered to point towards an object of interest. Declination is then locked, and right ascension slowly rotates, tracking the object as it makes its way across the night sky.

This mount makes use of advanced capabilities like GoTo and autoguiding. By connecting the mount's two main stepper motors to a central computer containing a database of celestial objects, the mount can automatically slew to a target. In addition, an auxiliary telescope and camera will provide live visual input, allowing the mount to automatically correct deviations in real time.