Equatorial Platform - Reagan's Dob Tracker
The best of both worlds - a Dobsonian mount with the ability to track the Earth's rotation. The equatorial platform moves with the earth's rotation for up to one hour, then it needs to be rewound. The eyepiece is always in an easy location for viewing and very accurate tracking is possible.
DC motor linear drive screw (left) equatorial platform controlled by an H.O. Train power pack - very close to the design of Warren Peters (see below).
My latest equatorial plarform (lower left) has a north cylindrical bearing and an axial south bearing.  It is driven by a rollerblade wheel that contacts the north runner directly.  It is powered by a stepper motor that turns a 10:1 reduction gear that is controlled by a microstepping controller.

A second stepper is used to make small corrections for errors in polar alignment and uses a ballscrew that has 3/4" of travel.  The second axis is driven by a standard stepper controller.

The scope (100 lbs of load) sits flat north to south and rotates 15-degrees east to west. It can fast forward, fast rewind, fast correct, and slow correct (see drawing of indexer / hand controller). A second hand controller is used for the second axis. This equatorial platform puts an axial bearing through the center of Warren Peters' south cylindrical bearing (see Warren's link below).
Details - Stepper Driven Platform with active design sheet for Warren Peters'directions (manual.html on the eqplatforms site - link below.

Choosing the type of drive for your platform.
Center of Gravity
Equatorial Platform Alignment - The Easy Way
My New Scope
Pictures taken with my Equatorial Platforms
More Equatorial Platforms
Both equatorial platforms were built using directions from Warren Peters (see below).  He gives excellent directions on how to build a basic equatorial platform. Warren's site is down right now. I have provided a link to the Yahoo Group "eqplatforms"  Go there to get Warren's document and to learn from the top EQ platform builders from all over the world.

I would be happy to help anyone that would like a hand building their platform. Just email me and we can work on any problems you are having. . Chuck is the father of equatorial platforms on the web and Warren used his site to build his platform. The jig that Chuck shows is really a great tool to help you get accurate centers on the cylindrical bearings.  I am thinking of using his tool and rebuilding my platform to increase the accuracy of the centers.

Build your own equatorial platform with directions from Warren Peters, Chuck Shaw, Dave Molyneaux, or Jan van Gastel - you'll be happy you did!
Would you like to show your platform and don't have a website? Send me your pictures and notes and I will post them under your name on the Webring (see below). All platforms are works of art that should be shown! If you have a website, just click "Join Now" at the top of this page.
Yahoo group "eqplatforms" and  Warren Peters' CACHED website. If you have any interest in platforms go here to learn from the best platform builders from all over the world (see FILES section).
Chuck Shaw's website
Please see the ATM links page for more great equatorial platforms
Jan van Gastel's website
Homemade Equatorial Platform Corner