next up previous contents
Next: The new TCS Up: Telescope Previous: Wavefront sensing   Contents


No more reports were received about poor pointing but our extensive tests have shown that the pointing varies significantly. The main result we found is that the pointing varies within a night, specifically it appears to depend on the time since the telescope power is switched-on (which is typically somewhere near the end of the afternoon). The pointing shows deviations in both azimuth and altitude which vary $\sim$sinusoidally as a function of azimuth, where the phase and amplitude of these sinusoids change with time. This means that any pointing can be either good or bad depending on when and where you are pointing, and not necessarily on when the last pointing model was made. In fact, we have not changed pointing model in the last 6 months.

We are currently still investigating what might cause the pointing to vary as a function of time since power-on of the telescope.

Thomas Augusteijn 2004-05-18