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Using the Deep Space Navigator with Telescopes
Mounted on Drive Platforms

The Deep Space Navigator can be used with a telescope on a drive platform--also known as a "Poncet Platform": a platform designed to drive Dobsonian telescopes. Typically a drive platform has some kind of short sector gear (sometimes as simple as a nut driving a threaded rod) designed to drive the scope for short intervals. To use it you would set the telescope on the platform with the platform motor turned off and the gear at its starting position. You would find the object of interest, then turn on the platform motor to keep the object in the field of view. The platform moves the entire telescope, base and all. When finished with viewing the object the platform is turned off and returned to the start position.

Deep Space, with the Deep Space Navigator telescope interface is calibrated under the assumption that the telescope base is stationary. When the telescope is being driven with a platform this assumption is not true. However drive platforms are not used continuously. They do not need to be driving while finding objects. They function only to keep an object in the field of view once an object has been located.

To use the Deep Space Navigator with a telescope on a drive platform the one mechanical requirement is that the platform must have a rigid, reproducible "starting position" to which it can be returned between driving sessions. Put the platform in this starting position with the drive turned off. Consider this to be "finding mode." Calibrate the Deep Space Navigator. Leave the drive motor off while finding objects. Whenever the telescope is in the start position the calibration is valid. Once an object is found you may turn on the drive motor which begins "tracking mode." At that point the calibration ceases to be valid until the motor is turned off and the platform is returned to the starting position.

As long as you keep a clear distinction in your mind between "finding mode" and "tracking mode" you can continue to use the Deep Space Navigator successfully throughout the night.