We all know him. In the morning, personified by the sun god Helios, he sets out with his chariot from east to west, bringing beneficial light to the Earth. In the west, his horses are watered and watered, and Helios gets into the boat built for him by the god Hephaestus. In it he then returns by the ocean, and in the morning sets out again on his celestial pilgrimage. So say the ancient Greek legends.
But it can also be described in a much less romantic way. 1,392,020 km diameter, 1.9891×1030 kg weight, temperature almost 6000 oC on the surface and almost 16×106 oC inside. 4.6 billion years old. These are the main characteristics of our sun, the central body of the solar system.
His portrait, taken with a specialized chromospheric telescope, was submitted to the Czech Astrophotography of the Month competition by astrophotographer Jakub Lieder. And it is really something to look at. The Sun is approaching its maximum activity, which is repeated after about 11 years. This period is of course not exact, it varies between 9 and 14 years. Therefore, we can't tell yet in this cycle whether we are already at the maximum or just approaching it. We won't know until months from now, when the processed observational data is available and we can be sure that the drop in activity is not some random fluctuation in the Sun's activity. The solar activity cycle was discovered in 1843 by the German astronomer Heinrich Schwab. It is also named after him as the Schwabe or Schwabe-Wolf solar cycle. Archaeological discoveries show, according to the study of ancient tree rings, that it was already in operation at least 290 million years ago.
In the winning image, we can see a wide range of phenomena that are visible in a layer of the Sun called the chromosphere. This is above the photosphere, which is visible to the naked eye. To observe the chromosphere, we have to use filters that "cut out" a very narrow part of the Sun's light around the spectral line of hydrogen H-alpha with a wavelength of 656.7 nanometres. It's a very thin layer about 3 to 5 thousand kilometres thick. In addition to observations with specialised "chromospheric" telescopes, it can be observed, for example, during a total solar eclipse.
Let's start by looking at the formations above the sun's edge, which we call solar prominences. The tallest ones in this image reach up to 50,000 km high, so we could hide almost four Earths in them. The density of the prominences is several orders of magnitude higher than the surrounding solar atmosphere, which we call the corona. That's where they emerge from the chromosphere. But the temperature is much lower - astronomers have found that almost two-thirds of the matter in a protuberance is less than 15,000 oC.
However, protuberances can be observed not only above the sun's edge, but also on the sun's disk. Due to the fact that they are cooler than the chromosphere captured here, we see them as dark hash-like formations (bright in the image as it is reproduced in the negative). We are equally intrigued by the bright (here dark) regions of the active Sun and the magnetic loops that make visible the complicated magnetic field of active regions on the Sun. And let's not forget the delicate fan-shaped tufts, the so-called solar mottles.
"In conclusion, we really have to thank the author for the nice view of the somewhat 'dirty' face of our Sun and for submitting the image to the competition. Congratulations on winning the August round and we wish you many similar photos," concluded on behalf of the jury ČAM Marcel Bělík from the Observatory in Úpice.
Author Jakub Lieder
Name:Sun
Place:Prague - Letňany
Date: 11 Aug 2024 6 pm
Sensor: ZWO ASI 174MMC, Astronomik UHC-E + Astronomik R + Daystar Quark Chromosphere
Optics: T-S 102ED, 4.2x, F/30 @ 3000mm
Installation:Nexstar Evolution
Description:Mosaic (36 fields), Autostakkert, Pixinsight, Registax, ICE, Gimp
You can see the winning images in each month and more information at http://www.astro.cz/cam/.
(za)/ gnews - RoZ_07
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