Deep sky sketching and zodiacal light 8./9.3.2013

Date: 8./9.3.2013
Time: 21:15-00:25
Observing site: Stormälö, Parainen, Finland
Instrument: L102/1000mm (4” Refractor), N250/1200mm (10” Newton)

NELM: 6,0
SQM: 20,84
Darkness of the background sky: 3
Seeing: 2
Transparency: 2
Weather: Clear sky, -12 °C, light wind, snow on the ground, no Moon, no aurora, zodiacal light in NW sky

Objects observed: Messier 53 (visual, sketching), NGC 2506(visual, sketching)

This was my first observing session in Parainen since September 2011! When I arrived at the site, I noticed that the winter Milky way in the Monoceros-Orion region was visible as well as it ever can be here in the conditions of Finland. Unfortunately winter is not so good time to make deep sky -observing in Finland because of cold temperature and snow, which is reflecting light in the sky. This can be observed with SQM, which gave values of ~20,8 around zenith. This is low value when compared with the good values in autumn, that can be as good as 21,2 in this site! NELM was barely 6,0 in Orion and about 5,7 in Ursa minor.

Besides Milky way and the ugly light pollution domes, I was able to see also another faint glow of light in the NW sky close to horizon. This light was rising from the horizon as a wedge -like glow of light that was following the line of ecliptic. This light was better visible with averted vision and sweeping. This light is better seen in the southern latitudes, but it can be seen also here in high latitudes around vernal- and autumnal equinox. This light is the zodiacal light! This was my second time to observe this phenomena from Finland. I observed this light for first time from the same site in March 2010. The zodiacal light can be seen almost every night in southern latitudes, but it is not common sight here in the high latitudes like Finland. The angle of the ecliptic is steepest around the time of the equinoxes, and that makes it possible to observe this phenomena!

Below you can see an excerpt with a sketch of the phenomena from my note book:

Zodiacal light observed 8.3.2013 in Stormälö, Parainen, Finland
Zodiacal light observed 8.3.2013 in Stormälö, Parainen, Finland

This time I was making deep sky -observations with two of my telescopes: N250/1200mm (10” Newton)  and L102/1000mm (4” Refractor). This time I observed NGC 2506, an open cluster in southern Monoceros and Messier 53, a globular cluster in Coma Berenices.

I observed NGC 2506 (Caldwell 54) with my 250/1200mm Newton. With this instrument, this open cluster appeared as a small, relatively condensed and concentrated cluster. The brightness range of the stars of the cluster is rather large, some brighter stars are clearly visible, but the fainter stars appeared only as a starglow in the background of the cluster.

NGC 2506 observed with 10'' Newton
NGC 2506 observed with 10” Newton

I observed Messier 53 with my both instruments. With 102/1000mm refractor @67x, this globular cluster appeared as a round, fuzzy nebula, whose brightness increases slightly inwards. No single stars were visible.

Messier 53 observed with 4'' Refractor
Messier 53 observed with 4” Refractor

With 250/1200mm newton @80x, the cluster appeared to be granulated, and few individul stars were resolved.

Messier 53 observe with 10'' Newton
Messier 53 observed with 10” Newton

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