Atmospheric dispersion corrector

When the ADC was first installed it failed for two reasons; the first problem was a mechanical relay failing, which was part of the arm movement control, and the second reason was during tests the spring that is part of the arm broke. Niels Michaelsen (CUO) provided a replacement (new designed) spring and we re-designed the arm control electronics, removing mechanical relays and now using a proper motor controller chip. The operation of the ADC has been successfully tested over long cables, this is so we can locate all the electronics outside the adapter. The electronics for both the arm and prism rotation have been mounted in a box ready to fit at a suitable external location on the adapter. The system still needs to be integrated in the TCS and the unit itself needs to be tested on the telescope.