One observing night at the Roque de los Muchachos at La Palma
I was on La Palma from January 15 to January 21 for a technical mission at the Mercator telescope. The weather was not very good, but I managed to get out the Orion Skyquest XT12i IntelliScope we have in the Mercator building on the first evening I was there. I forgot already that the sky is so unbelievably good from the Roque de los Muchachos. There was quite some wind, but I could hide behind the car, so the wind did not disturb me that much. The telescope has a right angle finder and a telrad, but the batteries of the telrad were empty, so I could not use the telrad. Pointing the telescope with only a right angle finder is very difficult, so it was not easy to find the objects I was looking for. It was quite cold, with a temperature of 2.3° when I started observing around 19h40 and a temperature of 3.7° when I stopped around 22h15. The humidity fell from 57.5% to 33.2% and the wind speed was around 6 m/s. I did not observe for a very long time, because I had to wake up ve