The program then can be made to point the telescope in such a way as to take account of the fact that the telescope has to be slightly mispointed to have it go to the correct position. In theory and fact this concept works. The major problem that one finds is that a mechanically unstable telescope or one that is very sensitive to loading will have a different mapping correction for each mechanical condition. The program can take care of this situation by remembering a different mapping for each major change in loading of the telescope. One can for example have a map for visual work, another for loading with a camera and guider telescope and still another for a guider and heavy piggy back camera and so forth.
Problems arise when the mechanics of the telescope are weak or marginal in some way.
That is, if the telescope does not repeat its goto position with repeatability. This is a very fundamental limitation with the particular LX 200 telescope on which I tried to apply T-Point. This telescope did not point reliably because it had significant flexibility and loosness in the bearings that did not appear to be repeatable or that changed from use to use. It was not determined if this was due to temperature changes, shifting of parts, inadequate bearings or whatever. It was clear that basic pointing accuracy was no better than 5 to 10 arc minutes at best and often as bad as 20 arc minutes from the desired location.