Nightlife of the sky or in search of Perseids

Nightlife of the sky or in search of Perseids Every year the Perseids indulge the inhabitants of the Earth with a beautiful spectacle (for the patient ones), and every year we have a desire to capture this moment in one way or another. Since this year the weather did not spoil us, we had to leave and start observations in advance. What came of it - read below
 
 
Just note, there will be few Perseids below, but we managed to shoot something that we thought was interesting: the real stormy life of the night sky, and it was not boring at all.
 
 
Attention! further in the article there will be quite large gif-animations of 3-5MB!
 
VC400 (Neva400) , this camera has the following characteristics from the measurements:
 
 
- Resolution: 2000х2000
 
- the size of the photosensitive element: 10x10 μm
 
- quantum efficiency: 95%
 
- reading noise: 2 electrons
 
- Dark current (at 25'C): 25 electron per second
 
 
All these parameters suggest a good opportunity for catching meteors. The only problem is optics. Finding a good fish-ah, which would cover the entire sensor, is not so simple, we used the following optics: Samyang 8mm f /3.5 AS IF MC Fish-eye
 
 
- focal: 8mm
 
- aperture: 1: ???r3r3226.  
- viewing angle approximately: 140x150 degrees
 
 
The lens did not completely cover the camera sensor, but maybe this is for the best, the quality of the lens is very mediocre, bright objects, it "washed" even in the center.
 
 
The camera with the lens was fixed to the mount with a clockwork (photo unfortunately not, because it was dark).
 
 
The shooting was held near Veliky Novgorod (hello white nights) from 10 to 11 August, on the shores of Lake Ilmen, the sky is not ideal, on the horizon it is highlighted by the city and the village.
 
 
The exposure was selected for 2 seconds, the shooting lasted 3 hours 15 minutes, the total number of frames was about 600? the permeability of a single frame was 8sv.v. The resulting video is 60 times faster.
 
 
But the result surprised us a little, the night sky turned out to be full of "life", earlier we did not manage to achieve such effect when shooting timeworks, but, as they say, it's better to see once than hear a hundred times.
 
 
video double-clipped in youtube:
 
 

 
the processing of frames is minimal: the dark frame is subtracted and the levels are tightened (for sophisticated readers) a direct link to a single compressed video and scaled to a resolution of 1080p (500MByte):
 
 
The link to the large file here is (for readers with a thicket) a direct link to the compressed video with a minimum loss in the original resolution of 1440p (1.9Gb):
 
A link to a very large file here is
 
 
Since we saw more unexpectedly than expected, we had to try to identify at least the most interesting elements (below, errors in identification are possible, because there is little experience in this, and there is no data on some group objects in the entire known reference book).
 
 
So: pairs of satellites (as it turned out - these are the satellites of the third generation of NOSS):
 
 
NOSS-3-8 A & B
 
 
 
NOSS-3-3 A & B
 
 
 
NOSS-3-7 A & B
 
 
 
Quite interestingly, two bright objects were caught, which fly almost synchronously - these are the third stages of the Cyclone-3 rocket. They are considered to be very dangerous objects (such stages 127), "chasing" satellites ( Habr.com/post/386427 ):
 
 
 
 
An interesting object with variable brightness turned out to be already out of order DMSP-5D1ZH
 
 
 
 
Three of the satellites:
 
 
It was possible to determine only one of the triples - the Chinese YAOGAN 9A 9B 9C:
 
 
 
 
about the devices NOSS [/b]
For triangular UFOs, glare can be received from the NOSS (Naval Ocean Surveillance system) system of satellites. They are moved by groups (often three sub satellites) at a distance of 30 to 240 km from each other, and eyewitnesses usually describe them as "moving constellations, between which other stars are visible." Flashes occur also when the sunlight is reflected. The systems of the first and second generation (three subsatellite) existed in orbit until 2012. The satellites of the third generation (two sub satellites) were first launched on September ? 2001. However, this does not mean that now in the sky can not see a system of three sub-satellites. In early 201? China launched the first NOSS-like triplet, which was almost identical to the orbital slope and height of the US NOSS.
 
about the apparatus Yaogan [/b]
Space vehicles such as Yaogan-9 are launched in groups of three satellites on a single launch vehicle. After launching the spacecraft, a characteristic orbital order is built: two satellites from each triple move in a single orbital plane one after another at a distance of about 120 kilometers, and the third spacecraft of the group moves in an analogous orbit, but shifted along the longitude of the ascending node by an amount of the order of 1 °. This construction, at the intersection of the equator, three spacecraft are lined up with an almost equilateral triangle with mutual distances of 120 150 kilometers. When moving over latitudes 63 ° of the northern and southern hemispheres of the Earth, the "triangle" degenerates into a "line", while the third ("side") spacecraft is approximately halfway between the two others, at a distance of about 60 70 kilometers from each of them.
 
about the meteor detection system MMT [/b]
The location of the MMT system is the Northern Caucasus, the village of Nizhniy Arkhyz. Geographical coordinates of the point 43 ° 38'59.5 "N /A. 41 ° 25'53.3 "E, the altitude above sea level is 2030 meters. The field of view of one optical channel is 80 square meters. degrees (10 ° x 8 °), the total field of view of the MMT system is 700 sq. m. degrees. The time resolution of the system is 0.1 s (10 frames per second), while the minimum glare of the detected object is the 12th stellar magnitude. The permeability limit for fast moving objects is about 9.5 10.0 zv. led:
 
 
 
 
According to the functional, the camera showed itself to be something akin to the MMT system, with which, unfortunately, we are not familiar and did not know about the article before it was made.
 
 
Unfortunately, we are not real astronomers, but only radio technicians. Maybe these frames are something ordinary, but they seemed to us, at least, interesting than we decided to share.
 
 
A little explanation [/b]
Alexey's opinion, why we got a little differently than usual: "Usually timeslips are shot at tens of seconds, satellites are smeared into tracks and" drowned "in background noise. The exposure is selected so that the Milky Way can be seen, and the fisheye lens is a dark lens. In our case, the exposures are short and the signal (satellite) /noise (sky) ratio is higher. The camera has a high integrated quantum efficiency and there are no color filters. "
 
In conclusion, I would like to note that, since we planned to shoot not what happened, the shooting modes are not optimal. We think that you can get a slightly better result, but, unfortunately, we have a rare sky (1-2 per month). If there are any recommendations on how best to organize the shooting or, perhaps, something special to remove - we will be happy to comment.
 
 
We also hope that the whole array can be processed for searching the Perseids proper, but so far, how to get rid of satellites is not very clear. If we get something interesting, we'll post it. Maybe someone will be able to prompt programs to detect meteors in the frame - we will be very grateful.
 
 
Many thanks to Vera and Lesha, who, despite all weather and organizational conditions, took a taxi with cumbersome equipment to a windy sandy beach, they were able to shoot interesting shots and conduct processing.
 
 
Many thanks to the organization NPK Photonics for the provided sensitive camera and permission to publish the materials.
 
 
ps: When using these materials, a link to the article is required.
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