for Celestron CGE Pro

Installation Guide of Telescope Drive Master

Encoder-adapter for Celestron CGE Pro mount

Important: the Azimuth polar alignment mechanism of this mount is too close to the end of the Ra shaft; this is why, unfortunately, it is possible to use TDM with CGE Pro mount on geographical latitudes between +55°and -55° only.

First of all, thank you very much for purchasing our product called "Telescope Drive Master" and congratulation for your decision. This system will improve the tracking accuracy of your Celestron CGE Pro equatorial mount dramatically independently from its original periodic error amplitude because both periodic and aperiodic errors of your mount will completely be eliminated using our real time, ultra high precision correction system, without using conventional autoguider. We guarantee that your tracking error will remain within 1" (one arc-second) range total (or ±0.5") within 95% of your exposure time. It means your mount will have the best tracking ability among the amateur and semipro equatorial mounts all over the world (even if your dome-shutter is closed...).

To achieve this unbelievable result, before the installation of your Telescope Drive Master, you need to complete a very accurate polar alignment process of course. Please find our proposed method to do that on the companion CD ROM or among website's documents.

TDM controlling system contains two main logical units or parts: a high precision encoder unit (encoder and its mechanical adapter) attached directly onto the RA shaft of the mount and an electronic device (a sort of "black-box" with connectors), which receives the electrical signals arriving from the encoder unit and sends control instructions to the mount's driver via its auto-guider input connector. So you will need to install the mechanical elements and the electronic device as well but do not worry: both of them can be done very easily.

Please find the drawing and description of electronic connections to be set in relevant part of User's Guide because this schematic is the same for every telescope mount. In this document you will find the mount specific instructions for mechanical adapter and encoder installation only.

Before starting it is highly important to emphasize that both encoder unit and its adapter elements are sensitive mechanical parts!!! Do not drop any of them; do not stress them during installation!!! Handle with care! Any damages of these parts can destroy product's accuracy.

Just Allen-wrenches (1.5mm and 2mm type), a Torch screwdriver (size#T9) and an adjustable wrench will be needed for installation.

Mechanical parts of the adapter have been assembled in one unit before delivery. The risk of any mechanical damage during transportation is much lower in this way but, it means, you need to disassemble them before installation.


Before assembling parts during installation, please always check and clean all of the threads and surfaces of the lower end of the RA shaft and encoder adaptor elements if necessary. Use clean clothes (not nylon!) for smooth surfaces and a dry toothbrush to clean the internal and/or external thread(s) of the RA hollow shaft if it is necessary. Only the clean and tight mechanical contact between surfaces will provide correct mechanical coupling and positions.

Step 1:

After fixing the RA shaft, rotating left, please remove the cup of the RA shaft.


Step 2:

Next step is attaching encoder shaft onto the shaft of RA axis. Do not touch the long cylindrical surface of the encoder shaft with any metal tool (e.g. pliers)!!!



Use wrench or adjustable wrench only at the bottom of this part clockwise, as you can see below in the picture.


Now, tighten it well enough. This part cannot have any offset compared to the RA axis. If shaft-threads and connecting surfaces are clean enough, the thread profile-angle will have to be able to centralize geometrical axes without any problem.

Step 3:

Please push the stator ring onto the casting house of the RA shaft completely.


While the stator is fully contacted onto the RA casting, please fix it in this position using Allen wrench on eight set screws as can be seen below. These screws will press the bits of the stator onto the internal wall of the casting for fixing this part on proper way. So please tighten them as you can.


Step 4:

Now, you need to install the "adapter neck" on the stator which is necessary to provide wider application possibilities on higher altitudes of geographical locations. (The Azimuth polar alignment mechanism of this mount is too close to the end of the Ra shaft; this is why, unfortunately, it is not possible to use TDM with CGE Pro mount on higher geographical altitudes then +/-55°.) Just screw it onto the stator as can be seen below.


As soon as you screwed the neck onto the stator, please fix the part in its position by Allen-wrench using the four set screws.


Step 5:

After fixing the stator, you can install the encoder coupling together with the encoder. Please find detailed description about this process at "New Coupling Install" here:



Using Torch screw (size#T9) tighten two screws well in the clamping ring on both ends of the encoder. At first, you can reach the screw on the front side via slots created in the flat springs especially for this purpose. Please tighten the front clamping ring while you push the encoder slightly onto the stator.


Now, please fix the second clamping ring.


And finally, tighten the coupling screws.


Step 6:

The main parts of the encoder adapter and the encoder have been installed so far. Now, please put the cover of the encoder to its place and fix it in proper position (cable slot is down) with three screws.


Step 7:

Now, please put the encoder cable to the gap created for this purpose and screw the holder of the original end-cap to the encoder cover tube to save the encoder against environmental influences.


Step 8:

Finally, put the original end-cup back to the holder of the adaptor.


Congratulation, you successfully installed the encoder onto your equatorial mount and you have finished the most difficult part of the installation process!!!



You just need to create cable connections among telescope electric units according to the relevant part of the User's Guide.

Additionally, please find several useful tips and tricks in the User's Guide of TDM and other documents found on companion CD ROM or visiting website.

original solarflare design by rhuk
modified by MDA-TelesCoop