Nebbia in Val Padana ... was so a week: dense fog in the plains, the Alps, with clear skies. It 'an ideal situation, many times you want that this time it was made Saturday in a New Moon. Destination Visdende
Val. We wondered what on earth would have had a night without light pollution Serbian. The answer in the picture (click to enlarge).
left the position last month, to the south Right on Saturdays (you can see Sirius, M41, Orion). The light of last month comes from the Po Valley at 60-100 km (there is nothing in the South before). The fog blocked the light and dark as much as the South was the North. I explored all sides with the camera but not c'era nessun segno di IL. L'airglow era visibile in tutte le direzioni, anche se il profilo dei monti impediva di vedere fino all'orizzonte (che diventa nero quando c'è solo airglow).
Per vedere l'airglow la cosa migliore, come mi ha spiegato Mars4ever, è stare seduti guardando lo zenit e cercare di ampliare l'angolo di vista fino a vedere l'orizzonte tutto attorno. Si vede il cielo un po' come in una fotografia con fisheye, e l'airglow tutto attorno è evidente.
La Via Lattea attraversava tutto il cielo. La parte estiva era fortemente strutturata, più uniforme quella invernale. Con un po' di attenzione si potevano vedere diverse gradazioni della Via Lattea estendersi molto lontano dal piano galattico, anche nella parte winter. The sky was far from uniform in intensity. Apart from the Milky Way and the airglow, the Gegenshein was also evident as a pale zone in the Pleiades and to the west. Above and below the gegenshein the sky was darker. You could also see the Zodiacal Band, which started from Gegenshein and towards the Milky Way (which was confused with this) is more apparent, continued westward where the limits of perception. The zodiacal light was more intense in the east gradually rising and that part of the sky seemed to be "polluted" than the rest. The darkest area of \u200b\u200bthe sky was the north east, the Big Dipper. Sirius, when it emerged from the mountains to the south-east was so intense as to disturb the adaptation in the dark. The SQM
started from 21:54 (first reading), is a bit 'down as they passed some cloudiness, and then stabilized at 21:50 from 11.10 (average of many readings with three different instruments in an SQM-L) to arrive around 21:55 to 2:30 at night. These readings refer to the zenith (SQM is normal for L version). Pointing the darkest part of the wagon SQM-L showed a mean value of 21.65 (between 21.62 and 21.69).
The veils that have gone in the first part of the night was slightly illuminated from below, from light coming from Santo Stefano di Cadore and Comelico (which were not under the fog). But little do so much so that their brightness was still I put more of the sky.
At some point in the night I also did a walk along the road towards the woods. The trees stood out Nerissa on the sky, and the sky seemed much brighter than the black silhouettes of trees.
The question remains of why the sky was only "21:55, since it lacked any light pollution. The explanation, in the days after investigating the matter, is that the airglow is a phenomenon that exhibits some fluctuations in intensity of short-scale (due to gravity waves in the atmosphere), other seasonal scale and ultimately other scale of 11 years due to the solar cycle. Those pitches appear to be connected to alternating hot and cold, with autumn and the first inverno i periodi in cui il cielo naturale è più luminoso e la primavera fino all'estate inoltrata in cui il cielo è più buio.
E' quindi probabile che abbiamo osservato un cielo naturale, ma in un periodo di massimo airglow.
La Val Visdende è a quota relativamente bassa: 1300 metri. Per questo è mediamente più calda degli altri siti in quota. C'erano infatti solo 5 gradi sotto zero. Il contro è che c'è più aria sopra e quindi un po' più di estinzione. M33 era l'unica nota stonata: visibile in distolta con un po' di difficoltà (presumo forse a causa della estinzione).
Il seeing è stato buono nella prima parte della notte: le stelle erano puntiformi a 260x (anche thanks to the fan who has always worked). In the second part of the night is a bit 'worse.
Compared to this time last month we arranged a bit 'in the valley below, in practice after clearing the last: 46 ° 37'24 .60 "N 12 ° 37'37 .20" E. There were trunks of trees, evidently the work of the woodcutters. And there was the smell of resin to keep us company. A few cars every now and then come in and changed direction (after the valley is closed).
We observed a large quantity of the items. Do not list them all but the most significant.
PK 93-2.1 planetary is a small diamond shape. You could take the form, a bit 'as in picture but much more tenuous, at high magnification.
PK 86-81 is another planet that you could catch a bit 'structure always at high magnifications.
invisible elephant's trunk BSI 142. Instead, Barnard was a fine show 168 species using 32 mm at 57x. You could follow the entire strip to the dark side where it expands. On the other hand, the Cocoon was clearly visible (preferably with a 86x 21 mm) and showed different internal irregularities.
observed Abell 77 with OIII and UHC filters at 260X, but seemed to have a very weak internal less bright (typical aspects of his eyes as the Owl).
PN M 2 5 1. Also observed at this inrandimenti similar.
In the meantime I did the photos impossessao Marco had the telescope. Among the objects selected by pointing and Mark mention:
NGC7177, NGC 1201 (we take advantage of the horizon south of observing objects bass), NGC 1255 (this one could guess the spiral shape), NGC1360 (a large planetary nebula that was very evident, including internal irregularities in the medium magnification OIII.
1532 NGC1531, a nice pair of galaxies. Of the greater is sensed irregularities. The couple 2293 2292 . NGC 2280 . NGC925 .
An interesting comparison was Thor's helmet, 30 cm and 40 cm. This object 10 cm extra make a significant difference, showing intricate structures and the shape of the helmet with much more clarity.
Another worth mentioning was the nebula planetary M46. They saw two stars, and internal, for high magnification, a ring with the center hole.
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