The largest errors in the pointing of the JCMT are held to occur as a result of the irregularities and joints in the telescope track. These are currently compensated for by a lookup table in the Telescope control software. The existing lookup table is obtained by the use of inclinometers[1].
The software to implement the modeling put forward in this document exists as the Track Surface Model program. Options available in the TSM program are referred to in the text below, for a full description of the TSM program see section 4 or refer to the programs internal help pages.