The Micro-Guider 5 Telescope to Computer Interface

The MG5 is no longer available - this page is left online for information purposes only.

The Micro-Guider 5 (MG5) is a telescope to computer interface device, which connects between two optical encoders mounted on the axis of a telescope and a PC's RS232 port. A suitable planetarium program, such as the Earth Centered Universe Pro, can interpret the data received on the RS232 port to determine the telescope's position.

The MG5 is the replacement for the older do-it-yourself Micro-Guider III (MG3) device which first saw the light-of-day in the early 1990s. The MG5 improves upon the MG3 by being smaller, lighter, faster, lower power, pre-assembled, etc. So what's the catch? Well, there isn't any! In addition, the MG5 comes assembled, tested, and ready to use.

What You Receive

The Micro-Guider 5 is shipped with the follow parts:

MG5 Specifications

Encoder compatibility Compatible with +5 volt powered, two channel incremental encoders. Electrical encoder connector pin-out matches encoder assemblies sold by Orion Telescopes and Binoculars and Jim's Mobile, Inc.
Software compatibility Compatible with Micro-Guider I and III command set. Emulates the 'Q' command of the Lumicon NGC Sky Vector, Celestron Advanced Astromaster and other similar devices. Emulates the 'Q' and 'Z commands of the Orion Sky Wizard CTI interface.
Encoder sample rate

16,000/sec in 'always-on' encoder power mode, 3000/sec in 'pulsed' encoder power mode.

Power requirements

+8 to +18 volts DC (unregulated) (a 12V auto lighter socket cable is supplied)

Power consumption

Less than 10mA (excluding encoders) at +9V DC

Physical Size (MG5 unit only)

3.25" x 1.75" x 0.8"

Weight (MG5 unit only)

~60 grams

Encoder interface connector


Serial interface connector

DB-9F (transmits on pin 2, receives on pin 3, with ground on pin 5) - plugs directly into your PCs 9-pin serial port.

Serial protocol

RS232 (DTE) 9600 baud, 8 data bits, 1 stop bit, no parity

DC Power connector

5.5mm OD x 2.1mm ID Coaxial



MG5 Links

MG5 Pictures

(The Earth Centered Universe, The Earth Centered Universe Pro, ECU, Micro-Guider, MGIII, and MG5 are trademarks of Nova Astronomics. Other trademarks are owned by their respective owners.)

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Last Updated: November 16, 2005.