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Flowing Night Sky
video
Created for the OAE
Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Time lapses of celestial patterns.
This time-lapse was shot from Slovakia in August 2020. By fixing the relative movement of the sky to Earth's rotation in some of the frames, we can experience a different perspective as a viewer.
The Milky Way, our home galaxy, is visible throughout the whole video. The bright objects near the Milky Way are Jupiter and Saturn, close together, Jupiter being the brighter one.
This video also shows the interaction of amateur astronomers observing the Perseids meteor shower with their telescopes pointed towards the sky. An unfortunate aspect of the art of astronomical observing, clouds can suddenly cover the whole sky. The fog occurs mostly because of the higher humidity after the rain.
Most of the light trails in the sky are made by satellites, but some of them, appearing just very briefly and not very noticeably, are meteors, as the video was shot around the peak of Perseids meteor shower.
Credit: Robert Barsa/IAU OAE
Glosar de termeni:
Jupiter , Milky Way , Saturn , Shooting Star
Categories:
Milky Way and Interstellar Medium
, Naked Eye Astronomy
, Stars
License: Creative Commons Atribuire 4.0 Internațional (CC BY 4.0) Creative Commons Atribuire 4.0 Internațional (CC BY 4.0) icons
This file on Zenodo ( video 254.11 MB)
Southern Sky
video
Created for the OAE
Caption: First place in the 2022 IAU OAE Astrophotography Contest, category Time lapses of celestial patterns.
This video is a compilation of several recordings taken on various occasions in June 2019, both on Easter Island and in the Atacama Desert in Chile. It starts with an impressive opening of clouds seeming to emerge behind the famous statues on Easter Island and moving directly forwards towards the observer. It evokes the impression of the mighty deities sending clouds to cover the night sky.
In the next couple of scenes, we see landscapes with an impressive Milky Way turning overhead, but this quiet scene is continuously interrupted by hasty satellites or — in one of the scenes — even by car lights on the ground. It illustrates both the majesty of the sky and the disturbance of nature by human influence.
Then there is another scene of clouds passing by, but now from left to right. The terrestrial clouds pass below the clouds of stars that form the Milky Way. The last scene shows an undisturbed still pattern of stars that looks like a flight over a zoomed-in photograph, and shows how we are not used to experiencing nature’s stillness and silence.
Credit: Jianfeng Dai/IAU OAE
Glosar de termeni:
Milky Way
Categories:
Milky Way and Interstellar Medium
, Naked Eye Astronomy
License: Creative Commons Atribuire 4.0 Internațional (CC BY 4.0) Creative Commons Atribuire 4.0 Internațional (CC BY 4.0) icons
This file on Zenodo ( video 526.21 MB)
Satellite swarm versus night sky beauty, by Torsten Hansen, Germany
image
Created for the OAE
Caption: Third place in the 2021 IAU OAE Astrophotography Contest, category Light pollution.
This image of Venus and the Pleiades also shows the tracks of the Starlink satellites. These satellites which are located at an altitude of approximately 550 kilometres, are part of an ever-growing constellation of satellites aimed to provide worldwide internet access. The reflective surfaces of the satellites, coupled with the fact that they are orbiting around the Earth, means that astronomical observations which require very long exposures capture “tracks” of the satellites in their images. Astronomical images used for scientific research are not usable because the measurements and data will contain these “tracks”. Because the number of satellites is expected to grow, it is likely that in the near future there will be no place on Earth where these satellites will not be visible crossing the sky. This is a new type of light pollution that seems to be an upcoming problem we will have to deal with, as these satellites might prevent optimal observation of the sky.
Credit: Torsten Hansen/IAU OAE
Glosar de termeni:
Light Pollution , Artificial Satellite
License: Creative Commons Atribuire 4.0 Internațional (CC BY 4.0) Creative Commons Atribuire 4.0 Internațional (CC BY 4.0) icons
This file on Zenodo ( image 5.66 MB)
Space debris orbiting the Earth
video
Caption: This animation shows objects orbiting the Earth. The data date from February 2024 and are taken from space-track.org which maintains a public catalogue of objects tracked by the United States Space Command (USSPACECOM).
At first in this video we see green dots, each representing one of the 31,000 human-made objects orbiting Earth. These include both operational and decommissioned satellites, used rocket stages from space launches, and fragments larger than 10cm created by collisions or explosions. Later in the video, some of the green dots are replace by orange dots, each of these representing one of the 9,300 operational satellites orbiting the Earth. Note that since February 2024 more satellites and rockets have been launched in to space and some objects will have fallen back to Earth, so these numbers will have changed.
We see two main groups of objects. The first are those objects orbiting close to the Earth, objects in low Earth orbit. These include communication satellites (many from the satellite constellations used to provide satellite internet services), Earth observation satellites, military satellites, two operational space stations and other objects such as rocket stages and other debris.
More distant from Earth we see a thin ring of satellites. These are in geostationary orbit. This is a special orbit where the orbital period matches the rotation period of the Earth. This means that a satellite in geostationary orbit stays above the same point on the equator and, when observed from the side of the Earth facing the satellite, will appear to stay at a position on the sky that does not change over time. Because of this, geostationary orbit is used by many communications satellites as a satellite dish on Earth used to receive or transmit a signal to that satellite can point in a fixed direction and does not need to dynamically track the satellite. Geostationary orbit is also used by weather observation satellites.
Credit: NASA's Scientific Visualization Studio
Credit Link
Glosar de termeni:
Artificial Satellite , Space Debris , Spacecraft
Categories:
Planet Earth
, Space Exploration
License: Public Domain Public Domain icons
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