Telescope Drive Master |
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What are Typical Results from the TDM? Most users of the TDM are making unguided images of up to 20 minutes or more in a single exposure with perfectly round stars. At left is a section of the Horsehead and Flame Nebula in Orion as taken by István Gyarmathy, using an unguided Fornax 51 mount with the TDM. Exposure was seventeen stacked, five-minute exposures. And here are more examples of long-exposure, unguided astrophotos taken with the TDM installed:
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Jack Newton and the TDM "The unit required 30 minutes to install (only because I did not take the 16-inch LX200 apart). The Telescope Drive Master was turned on and started working immediately while my supernova run was activated, at 72 images an hour. The initial result: 90% of my images had no guiding error with the TDM running. My 16-inch LX200 Classic has no PEC on the internal chips, (so my yield of perfectly round stars without some sort of guiding assist is very few). This makes it a worst-case scenario for the Drive Master to correct!" |
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What Is the Telescope Drive Master? Designed to attach to popularly available equatorial mounts, the Telescope Drive Master™ (TDM) uses a mount-specific adapter, an ultra-high resolution encoder, and an electronics package that transforms your drive system into a super-performance, research-grade drive. This device does not require tedious PEC training, just turning on the TDM almost eliminates all of the periodic and non-periodic tracking error of your equatorial mount. |
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How Does the TDM Work? The electronic controller unit compares the signals incoming from the high precision rotary encoder mounted onto the RA shaft with the time signal of its quartz oscillator. Any deviations of the angular velocity of the RA shaft from the prescribed drive rate, are compensated by feedback regulation in real time by accelerating or slowing down the drive. If further correction is needed because of errors other than periodic drive error, the TDM allows auto-guider input as well. |
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How Much Better Can My Drive Perform? A typical drive on an moderately-priced equatorial mount can easily have 20-30 arc seconds (or more) periodic error. The Telescope Drive Master can easily improve it down to 2-to-2.5 arc-seconds peak-to-valley or less, which is what you would expect from equatorial mounts that cost many thousands of dollars. However, it is possible to get even better performance with the TDM. Attila Madai explains: "TDM’s control range is +/-0.5 arc-seconds (or 1” ptv) in more than 95% of the exposure time in optimal case. The user needs to test and adjust guide control speed of the Hand Controller (e.g. Autostar): which fits to Controller-TDM combo on the best way. (Optimum point can be found between 0.15x and 0.5x sidereal speed; depending on the mechanical behaviour of certain mount and monitoring frequency of HC’s guide input port.)" |
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How Can I Test the Performance of My Drive? You can download TDM Monitor software free of charge! This program can read TDM correction values in real-time via the PC serial port (or via RS232-USB adapter) from USART Port of TDM box. The installation package contains the LabView runtime environment as well for using this application. In this way, the user can check tracking error of any mount in real time in his/her warm room (without autoguider support). There are two versions of “TDM Monitor”: v1.0 with +/-16” (1/8” resolution) or v2.31. Both have +/-16” (1/8” resolution) and +/-32” (1/4” resolution) range of tracking deviation display. Before installation, it is recommended to read "ReadMeFirst.txt" file. |
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