Halos in the sky of Seitseminen National Park, Finland 25.8.2012

Observed phenomena: Halo phenomena
Light source: Sun
Origin: High clouds (cirrostratus)
Observed halo forms:

  • 22° halo
  • Upper tangent arc
  • Parhelia
  • Circumzenithal arc
  • Supralateral arc
  • Upper suncave Parry arc

Date: 25.8.2012
Time: 18:16-19:23
Observing place: Kuru, Ylöjärvi, Finland
Observing method: Photography
Technical information about photographing equipment: Camera: Canon EOS 1100D, lens: Canon EF-S 18-55mm IS, Samyang 8mm fish eye

In the evening of 25th of August 2013 I noticed that there are some halos in the sky. I took my camera and started to observe and take some photos. In the beginning, there were only some ordinary everyday -halos in the sky (22° halo with parhelia), but then something more interesting appeared in the sky! An upper tanget arc and upper suncave Parry arc appeared with 22° halo and parhelia! Later also circumzenithal arc and supralateral arc (or 46° halo) joined with the other halo forms.

This was a pretty nice halo display, luckily I stayed and observed and documented it thoroughly! This was also the very first time for me in my life so far to observe the Parry arc (and the upper suncave subform of it)!

Below you can see photos from the halo display. All photos are unsharp masked.

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The outburst of SS Cyg is over for now 23./24.8.2012

Date: 23./24.8.2012
Time: 00:45-02:10
Observing site: Visitor Centre, Seitseminen National Park, Finland
Instrument: L102/1000mm (4” refractor)

NELM: 5,7
SQM: 21,17
Darkness of the background sky: 2
Seeing: 2
Transparency: 3
Weather: Mostly clear sky, light wind, no Moon, humid air, 8°C

Objects observed: SS Cyg (visual), R Tri (visual), T Cas (visual)

During this session, observing conditions weren’t so ideal than during the last session. This time transparency and hence NELM were not so good. SQM was about 21,17 and NELM 5,7. Nevertheless the conditions were good enough for observing variable stars, although not so optimal for DS sketching. That’s why I observed only variable stars this time.

It seems that the outburst of SS Cyg is over now, and the star is going back to it’s normal brightness. The duration of this outburst was about 14 days, which means that this was a long outburst for the star. You can see the AAVSO light curve of the star here. Besides SS Cyg, I observed also R Tri and T Cas. R Tri is getting fainter, and T Cas is still around it’s maximum.
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Variable star observations:

Date Time Star Mag. Comp.
23./24.8.2012 01.04 SS Cyg 9.8 9.8/10.8
23./24.8.2012 01.30 R Tri 8.2 7.7/8.0
23./24.8.2012 02.00 T Cas 9.2 8.8/9.2

Observing in really good conditions 22./23.8.2012

Date: 22./23.8.2012
Time: 00:15-02:20
Observing site: Visitor Centre, Seitseminen National Park, Finland
Instrument: L102/1000mm (4” refractor)

NELM: 6,6
SQM: 21,27
Darkness of the background sky: 1
Seeing: 2
Transparency: 2
Weather: Clear sky, calm, no Moon, humid air, 10°C

Objects observed: SS Cyg (visual), U Umi (visual), Messier 56 (visual, sketching)

This session was again really dark, actually it was the new darkest session so far this season! During this session I recorded the best SQM -reading so far, 21,27! Also NELM was really good, 6,6. This time it wasn’t luckily so cold as it was last time, during this session temperature was about 10°C. The sky was mostly clear during the session, although there was some clouds in the sky, but they weren’t causing any major disturbance.

During this session, I was observing SS Cyg again, which is now showing signs of declining brightness. Í estimated that it’s brightness was about 9.2. Another variable star that I observed was U Umi, and i estimated that it’s brightness was about 10,4. Also this star is getting fainter now.

Besides variable stars, I observed deep sky too! It would have been a shame to not observe any deep sky objects because the conditions were so great! This time I observed and sketched Messier 56, a globular cluster in constellation of Lyra.

Messier 56: @ 133x, round, fuzzy nebula, not resolved into stars. Pretty even brightness distribution, no obvious central brightening.

Messier 56 observed with 4'' Refractor
Messier 56 observed with 4” Refractor

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Variable star observations:

Date Time Star Mag. Comp.
22./23.8.2012 00.39 SS Cyg 9.2 9.2/9.8
22./23.8.2012 02.10 U Umi 10.4 9.6/10.6

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

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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

17./18.8.2012 – observing in best conditions so far this season

Date: 17./18.8.2012
Time: 01:50-03:00
Observing site: Visitor Centre, Seitseminen National Park, Finland
Instrument: L102/1000mm (4” refractor)

NELM: 5,8
SQM: 20,87
Darkness of the background sky: 2
Seeing: 2
Transparency: 2
Weather: Clear sky, calm, no Moon, humid air, 11°C

Objects observed: SS Cyg (visual), T Ari (visual)

During this night, sky got clear quite late, but when it got clear, the conditions were really good, best so far this season! The sky was darker than earlier this season, SQM reading was about 20,87!During this session I observed SS Cyg again, which is still in it’s bright state. Besides SS Cyg, I observed T Ari as a new star for me. This star is also underobserved, and needs more attention!

I estimated it’s brightness to be 9,0, but I noticed quite large discrepancy between my and observations made by other AAVSO observers. There are only handful of recent observations of this star in the AAVSO database, which of course makes it more difficult to assess the behaviour of this star exactly. I planned to observe this star again next night if the sky is clear to make sure, that I wasn’t making any too big error with the brightness estimation. One possible source of error could be the fact that the condensation of moisture was very intense last night and all the optical surfaces could have been covered with dew..

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Variable star observations:

Date Time Star Mag. Comp.
17./18.8.2012 02.10 SS Cyg 8.6 8.6
17./18.8.2012 02.45 T Ari 9.0 9.0/9.5

16./17.8.2012 – checking SS Cyg

Date: 16./17.8.2012
Time: 00:00-01:15
Observing site: Visitor Centre, Seitseminen National Park, Finland
Instrument: L102/1000mm (4” refractor)

NELM: 5,7
SQM: 20,66
Darkness of the background sky: 3
Seeing: 3
Transparency: 3
Weather: Partly cloudy sky, calm, no Moon, humid air, 12°C

Objects observed: SS Cyg (visual)

This time I observed only SS Cyg because I have now observed practically all stars in my observing programme quite recently. Also there was some cloud interference and I was quite tired because of staying up so much during recent nights. Only one observation from last night because of these reasons. SS Cyg is still in it’s maximum, but it is too early to say anything about the nature of this particular eruption.

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Variable star observations:

Date Time Star Mag. Comp.
16./17.8.2012 00.30 SS Cyg 8.3 7.7/8.6

15./16.8.2012 – quick observations in Seitseminen

Date: 15./16.8.2012
Time: 02:00-03:00
Observing site: Visitor Centre, Seitseminen National Park, Finland
Instrument: L102/1000mm (4” refractor)

NELM: 5,7
SQM: 20,66
Darkness of the background sky: 3
Seeing: 2
Transparency: 3
Weather: Mostly clear sky, calm, no Moon, humid air, 12°C

Objects observed: SS Cyg (visual), SV And (visual)

This time it was mostly cloudy during early night, but around 2am the sky got clear enough to make observing possible. Also this time I checked SS Cyg, which is still in it’s maximum. Besides SS Cyg, I also observed a new star to me, SV And. It is located in easy place, close to Z And. Both stars can be easily located with a Y -asterism in Andromeda.Some active observers in AAVSO have started an observing programme called “adopt an LPV!”. The idea of the campaign is to try to get better observation coverage for some currently underobserved Long Period Variables. SV And is one of the underobserved stars in the campaign, and I decided to adopt the star. It means that I’m trying to observe it once a week whenever possible to help the star to get better observation coverage.

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Variable star observations:

Date Time Star Mag. Comp.
15./16.8.2012 02.15 SS Cyg 8.6 8.6
15./16.8.2012 02.45 SV And 12.7 12.5/12.9