Instruction manual

21
4. Temperature Compensation
Introduction
This button on the main control screen brings up the temperature compensation function of RoboFocus.
Because many scopes shift focus with temperature, it is desirable to be able automatically to adjust the
focus as the temperature changes during the observing session. Temperature is sensed using a sensor in the
RoboFocus control box, or by an optional separate sensor that attaches to the telescope.
For RoboFocus to compensate for temperature changes requires that the RFCP know the relationship of
focus movement to temperature changes. That is, how many RoboFocus counts per degree are required to
maintain focus through an operating temperature range. This factor is called the temperature coefficient or
“slope”. The slope is entered into the RFCP directly by the operator.
Preparing for use of temperature compensation requires that the user obtain or calculate the coefficient. A
usable temperature coefficient could be obtained from another user that has the same scope setup and has
already calculated it. Or the user may develop a coefficient by manually recording focus data at several
temperatures and calculating the focus change per temperature unit. It can also be obtained by using the
RoboFocus training routine, which automatically provides a coefficient after the user has stored scope
focus data at several temperatures.
Having obtained the coefficient via a training file or otherwise, it is entered into the RFCP via the Slope
Setup window. The actual measurement of temperature and movement can be done manually (via a mouse
click) or automatically on a timed basis.