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Neowise's metamorphosis, by Tomáš Slovinský and Petr Horálek, Slovakia
image
Created for the OAE
Caption: First place in the 2021 IAU OAE Astrophotography Contest, category Comets.
This image uses the chronophotography technique to capture the evolution of the comet C/2020 F3 (Neowise) over time, as it became visible in the northern skies in July 2020. Orbits of comets are extremely elliptical, which means that during part of their orbit they get close to the Sun. As a comet approaches the Sun, it gets heated, releases gas and dust creating an envelope or coma around the nucleus. The solar wind and photons (particles of electromagnetic radiation) interact with the coma producing the cometary tail, which can be seen clearly in this image. The tail of a comet always points away from the Sun, and extends as much as tens of millions of kilometres. This tail has two parts: the relatively straight bluish gas (ion or plasma) tail, which is made up of charged particles interacting with the magnetic fields of the solar wind; and the whitish dust tail compose of very small dust particles that are pushed by the radiation pressure from the Sun into a curve due to their slower speeds. Two regions in the Solar System are often associated with being “storehouses” of comets: the Kuiper Belt and the Oort Cloud. Comets with periods up to about two hundred years come from the Kuiper belt, a reservoir of cometary nuclei material with a disk-like shape located beyond Neptune. Longer period comets come from the Oort cloud, another huge reservoir of icy objects, with a spherical shape surrounding the Solar System. The outer limit of the Oort Cloud is not known as yet, but it could be as much as 10 thousand times the Sun-Earth distance, or even more. Due to gravitational disturbances, some of these cometary nuclei might be ejected towards the inner regions of the Solar System, sometimes approaching the Earth, offering some of the most spectacular views of a celestial body. The image also shows some prominent constellations and asterisms like the Big and Little Dippers, and also the North (Pole) Star – Polaris.
Credit: Tomáš Slovinský and Petr Horálek/IAU OAE
Glossary Terms:
Comet
Categories:
Naked Eye Astronomy
, Solar System
License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons
This file on Zenodo ( image 19.53 MB)
Big Dipper and Comet Neowise C2020 F3
video
Created for the OAE
Caption: Honorable mention in the 2023 IAU OAE Astrophotography Contest, category of Time-lapses of rotation of Big Dipper or Southern Cross.
This time-lapse documents the trajectory of the iconic Big Dipper across three frames taken in July 2020. Captured from three locations in Italy, Tre Cime di Lavaredo Auronzo di Cadore, Monte Rite, Cibiana di Cadore, and Casera Razzo, Vigo di Cadore, this visual odyssey showcases the captivating journey of the Big Dipper with the addition of trails of stars painting a celestial canvas. It not only traces the path of this renowned asterism but also features the rare appearance of comet Neowise C/2020 F3, an extraordinary event that graced our skies during July 2020.
Credit: Giorgia Hofer/IAU OAE (CC BY 4.0)
Glossary Terms:
Big Dipper , Celestial Pole , Celestial Sphere , Circumpolar Stars , Polaris , Sky , Rotation
Categories:
Naked Eye Astronomy
Tags:
astrophotography
License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons
This file on Zenodo ( video 51.23 MB)
Perseids 2020 over Dark Sky Park Poloniny, by Tomáš Slovinský, Slovakia
image
Created for the OAE
Caption: Second place in the 2021 IAU OAE Astrophotography Contest, category Meteor showers.
A meteor shower occurs when the debris originated from comets or, on rare occasions, from asteroids enter the Earth’s atmosphere at high speed, leaving behind beautiful tracks in the sky due to friction with the atmosphere. This all-sky image taken in Slovakia in 2020 shows the Perseid meteor shower in a vivid way so one can really see the Perseids appearing all over the sky. This meteor shower is named so because the radiant point (the point on the sky where the meteors misleadingly seem to originate from) of the Perseid meteor shower is located in the constellation Perseus. This is a very prolific meteor shower, and a very popular phenomenon that can be observed from mid-July until mid-August, when the peak of activity happens. This is associated with the comet 109P/Swift–Tuttle, as Earth's orbit around the Sun crosses the debris left behind by this comet. This kind of image is very useful for full dome projections in planetariums, beautifully showing the Milky Way, our home Galaxy.
Credit: Tomáš Slovinský/IAU OAE
Glossary Terms:
Shooting Star
Categories:
Naked Eye Astronomy
License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons
This file on Zenodo ( image 17.24 MB)
Gemini meteor shower, by Hao Yin, China
image
Created for the OAE
Caption: Third place in the 2021 IAU OAE Astrophotography Contest, category Meteor showers.
As the Earth travels around the Sun, it may cross the path of debris left behind by a comet or, more rarely, by an asteroid. These debris enter the atmosphere at high speed, producing beautiful tracks as they burn in the sky due to friction with the atmosphere. The image captures the Geminid meteor shower, named because the radiant point is located on the sky in the constellation Gemini. The particles composing the meteor shower travel at similar speed and in parallel trajectories, which causes a perspective effect like if the stream radiates from one single point in the sky, which is known as the radiant point. This image, taken in December 2020 in China, clearly shows this perspective. This is a very prolific shower, in such a way that over one hundred meteorites could be seen per hour in recent appearances. This meteor shower is one of the few associated not with a comet, but with an asteroid – 3200 Phaeton, which might be a comet that lost all its volatile material. This image shows the large number of meteors that can be observed in this shower, which always happens in December every year. The image also shows one of the most prominent constellations in the night sky, Orion, easily seen by the three stars in a diagonal making up Orion’s Belt, and the red-orange star Betelgeuse. Right above the dish is a bright point and that is the Sirius, the brightest star in the night sky and part of the constellation Canis Major. The fuzzy bluish smudge at around 2 ‘o’ clock is the Pleiades star cluster.
Credit: Hao Yin/IAU OAE
Glossary Terms:
Shooting Star
Categories:
Naked Eye Astronomy
License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons
This file on Zenodo ( image 9.78 MB)
Geminid Meteor Shower from China, by Dai Jianfeng, China
image
Created for the OAE
Caption: First place in the 2021 IAU OAE Astrophotography Contest, category Meteor showers.
A meteor shower occurs when the Earth in its orbit around the Sun, passes through a debris trail left previously by a comet on its approach around the Sun. As the Earth enters this debris (small sand grain sized), they enter the atmosphere at high speeds and on parallel trajectories, burning completely leaving beautiful tracks (streaks) in the sky. These streaks can appear and disappear in the blink of an eye, or last much longer. On rare occasions the debris originates from asteroids, as in the case of the Geminid meteor shower, shown in this image, picturing many streaks of debris captured in the sky of China in 2017. Due to relative motions and perspective, the shower appears to come from one single point, known as the radiant point, beautifully pictured in this image. This is similar to driving in a car on a rainy day without any wind, looking out the front window it seems that the rain is coming directly towards the window, when in fact the rain is falling vertically downwards.
Credit: Dai Jianfeng/IAU OAE
Glossary Terms:
Meteoroid , Shooting Star
Categories:
Naked Eye Astronomy
License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons
This file on Zenodo ( image 26.78 MB)
