Date: 15./16.2.2016
Time: 20:30-22:30
Observing site: Leistilänjärvi, Nakkila, Finland
Instrument: N250/1200mm (10” Newton)
NELM: 5.3
SQM: 19.30 – 19.00
Darkness of the background sky: 5
Seeing: 3
Transparency: –
Weather: Clear sky, calm, snow on the ground, first quarter Moon in the sky, -10 C
Objects observed: NGC 1535, NGC 2539
In the night between 15th and 16th of February 2016 me and three other active members of Porin Karhunvartijat (Jarkko, Tomi and Santeri) drove to Leistilänjärvi, Nakkila to do some observing.
Leistilänjärvi is located in municipality of Nakkila in central Satakunta region, just 20 km SW from Pori. The place is a very large field, that has originally been a lake, but it has been dried out and transformed into agricultural land. The horizon is really open to all directions, there aren’t virtually any obstacles in any direction, se there is a true zero -horizon in that place. The downside of the place is that it is located in the immediate vicinity of the urban conglomerate of Pori-Ulvila-Nakkila-Harjavalta, which means that the place is very light polluted. In the middle of the fields, there aren’t any street lights of course, but the sky is not dark at all. The Bortle class of the place is perhaps 5 (subruban sky).
During the night when we were out observing there, the conditions were far from being optimal, and that was partly caused by the everpresent lightpollutedness of the sky, and also by 1/4 Moon that was shining at high altitude in the southern sky. Also there was snow on the ground, which was degrading the conditions even more. During the night, I also was having problems with the collimation of the mirrors of my telescope, and that’s why I couldn’t use high magnifications at all.
During the night Jarkko and Tomi were observing planet Jupiter, that had already risen above the horizon, and Santeri as a newcomer was learning by watching the pursues of the others.
During the night, I had some deep sky -objects on my list, even though the conditions weren’t optimal. During the night I observed two objects: NGC 1535 and NGC 2539.
NGC 1535
NGC 1535 is a planetary nebula in the constellation of Eridanus, which is best visible in midwinter. It is located at pretty low altitude in Finland, but nevertheless I tried to observe it. Here are my notes from NGC 1535:
@75x: Large and bright planetary, the shape of the nebula appears to be a round and symmetrical disc. The center of the nebula seems to be a little bit brighter than the outer parts.
NGC 2539
After I had finished observing this winter-planetary, I went on to observe an open cluster NGC 2539 in constellation of Puppis. The object is located in the northernmost part of Puppis, and it is located 8 degrees south from Alpha monocerotis. Of this object, I wrote following notes:
@80x: Faint-starred, a little bit scattered cluster without any significant concentration. Because of low altitude and poor conditions, only the brightest stars of the cluster were visible. The cluster is located next to 4,7 mag star 19 Puppis.
Celest1al Sphere 
Nice report. We suffer from light pollution here as well but the Bortle class is 6. The closest dark sky site is more then an hours drive so if seeing and transparency optimal, we don’t go. I have observed both of these objects however and they do stand up to light pollution fairly well.
Hello, thanks for commenting! I have similar situation here, I have one hour drive to the closest dark sky -place. Light pollution is just something that you have to live with and adapt to it. For example choosing right targets for the prevailing conditions – when observing in light polluted site (which is usually near home), observe bright objects and when you have opportunity to drive to the dark place, focus on fainter objects then.