GeminiFocus January 2016 | Page 17

Figure 4. GMOS-N g band zero point as a function of time. The various mirror coatings and CCD installations are marked with vertical dotted lines. Far right is the recent uptick due to the recoating of M2. primary at Gemini South. The beneficial effect of a fresh coating on M2 is clearly seen in the GMOS-N zero points shown in Figure 4. In Chile, the coating of the Gemini South primary mirror was a team effort, with staff attending from both Gemini sites, CerroTololo-Inter-American Observatory, and the Southern Astrophysical Research (SOAR) telescope. The results were excellent. Also in the south, we continued to modify the cooling arrangements for the top-end control computer; the warmer ambient temperatures on Cerro Pachón have caused problems v