20./21.8.2012 – darkest and coldest session so far

Date: 20./21.8.2012
Time: 23:45-03:00
Observing site: Länsi-Aure, Kuru, Finland
Instrument: L102/1000mm (4” refractor)

NELM: 6,2
SQM: 21,15
Darkness of the background sky: 2
Seeing: 3
Transparency: 2
Weather: Clear sky, calm, no Moon, humid air, -2°C

Objects observed: SS Cyg (visual), R Cyg (visual), Z And (visual), Messier 12 (visual, sketching), Messier 74 (visual, sketching)

This session definetly was the darkest but also coldest so far this season! During this session, the sky was totally clear and relatively dark, and the temperature dropped below freezing, being -2°C on average! It isn’t usually this cold in August, but this time it was! Coldness and intense condensation of moisture made observing very difficult, but nevertheless I was still able to observe SS Cyg, R Cyg and Z And. This time I was also sketching some deep sky -objects, this time I observed and sketched globular cluster Messier 12 in Ophiuchus and face-on spiral galaxy Messier 74 in Pisces.

In early evening I observed a satellite that cought my eye, there was a very bright and slow satellite moving downwards in the constellation of Aquarius. It was visible for about 10-15 s before fading away. I was curious about this, and after a little research I found out that it propably was a satellite called “Object G”, which is a somekind of a Cubesat. Cubesat satellites have been made in student projects in different universities in many countries around the world and they have been launched in February this year from French Guyana in South America.

Messier 12: while I was doing this sketch, the object was already at very low altitude in the horizon. @67x, this globular cluster appeared as a round, fuzzy nebula. The apparent surface brightness of this object is fairly low. Visually it is pretty faint, but the fact that it was low in the horizon could have had an effect on this. The cluster gets gradually a little brighter towards the center. It is possible to discern couple of individual stars of the cluster with averted vision.

Messier 12 observed with 4'' Refractor
Messier 12 observed with 4” Refractor

Messier 74: @31x, this face-on galaxy was visible as a very faint, small, round and fuzzy nebula without any observable details. The galaxy has an even brightness distribution and the surface brightness of the galaxy is very low. The object is best visible with averted vision and it even disappeared when gazing it with direct vision and it doesn’t tolerate any higher magnification. The optimal magnification for this object is as low as possible for an instrument like this.

Messier 74 observed with 4'' refractor
Messier 74 observed with 4” refractor

Variable star observations:

Date Time Star Mag. Comp.
20./21.8.2012 00.05 SS Cyg 8.7 8.6
20./21.8.2012 02.20 R Cyg 9.1 9.9/8.9
20./21.8.2012 02.45 Z And 10.3 9.1/10.4

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