I have had unbelievable luck, because it has been two clear nights in Sotkamo in a row! The second night was 1./2.10.2011. In early evening, observing conditions were really good, and I was getting SQM readings like 21.30-21.50! This time it was calm, and because of that, all moisture condensed very eagerly to all optical surfaces. That became as a problem around midnight, and in same an aurora arc had appeared in the northern sky. That arc started to spread towards zenith, and it really ruined the observing conditions, SQM reading dropped from 21.30 to 20.90. The degradation of observing conditions because of extreme humidity and aurora made me to stop observing about 15 minutes past midnight.
Anyway, during early night, I observed and sketched Messier 13 and 57.Messier 13 was stunning as always, it was easy to resolve Messier 13 almost to the core of the cluster. Messier 57 was visible as beautiful oval -shaped nebula, and the ring shape was obvious with averted vision.
Here’s the summary of the observing session:
Observing session: #15/11-12
Place: Torinkylä, Sotkamo, Finland
Instruments used: L102/1000mm
Objects observed: Messier 13, 57
Conditions: NELM: 6.8, SQM: 21.45, 0 °C – -2 °C, clear sky, calm, moist air, in early evening good, dark sky, aurora borealis in the end of session, I had to stop observing because they made the background sky too light.