adolfodarriba@terra.es Updated the day: 10 of September of the 2.008

Las Casqueras Astronomical Observatory 41º 39' 48" N 3º 29' 26" W 937 Mts From my beginnings in 1.991 to 1,999 it hardly observed from Valdelaguna (Madrid) 35 Km of Madrid, to about 740 meters of altitude. With the step of the years, the light contamination on the part of Madrid and Aranjuez to about 25 Kms. of distance, it had become untenable and I also observed inside an urbanization adding him but lights of beacons and neighbors' lights, and I could only look toward the Northeast to the Southeast, without being able to lower but there of -10º of South decline, but even so I ended up doing at first sight until the magnitude 7´2 in the best nights and my magnitude limit with the telescope, of 15´0 to at 15´5. Now I observe from Peñaranda de Duero (Burgos) about 17 km of Aranda de Duero a height of about 930 meters. At first it thought that it was a site really very good, so that before it observed from a very bad site. With observing I have realized that is a very humid site with continuous fog that a very considerable increase of luminance contamination of all the towns of but the lights of Aranda de Duero causes around. And in summer I have the normal problem of calima. I at least have a very ample horizon in all the directions. Even so, my normal magnitude is of 7,0 and how exceptional cases, I have arrived up to 8,3. The magnitude limit with the telescope in a normal night is from 15,0 to 15,5. If the night is very good, of 16,5 to at 17,0. The that more it impresses me in a very good night it is the brightness of the night sky. It is as if there was Moon when there is not it. I have the sensation of an increase of the light contamination that arrives until the Zenith, when the reality is that it is a very dark and clean night. I use a telescope C8-SP of 203 mm to F/10 de Celestron, with German mount and controls of slow movement. The eyeglasses are of 30 mm (68x) and 12´5 mm (162x). Ground not to use the Barlow lens because the same telescope already provides one long focal one to me. The day temperature normal winter is of 5º C The night temperature normal winter is of -5º C The day temperature summer is of 35º C The night temperature normal winter is of 25ºC