Where the Sun Sets Every Month

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Created for the OAE

Caption: Third place winner in the 2023 IAU OAE Astrophotography Contest, category of Still images of sunrise and sunset location over the year. Taken with a smartphone from San Rafael, Bulacan, Philippines, this series of images capture the changing position of sunset over the year owing to Earth’s axial tilt and orbit around the Sun. From January to December 2022, each image reflects the changing backdrop and position of the Sun at dusk. Observe the changing foliage and the appearance of an electricity pole in October. This collection serves as a visual testament to the celestial dance between Earth and the Sun, and the natural transformations on the ground.
Credit: John Paul Pile/IAU OAE (CC BY 4.0)

Glossary Terms: Equinox , Solstice , Summer Solstice , Sun Path (Day Arc) , Winter Solstice
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 ( image 11.82 MB)

Occasive Amplitude

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Created for the OAE

Caption: Second place winner in the 2023 IAU OAE Astrophotography Contest, category of Still images of sunrise and sunset location over the year. Captured from Gatto Corvino village in Sicily, this composite showcases the Sun setting at various points over the sea from the winter to the summer solstice (2016–2017). The centre frame marks due west. As Earth orbits the Sun, the position of the setting (and rising) Sun changes from being northward of due west (east) in summer to southward of due west (east) in winter. During the equinoxes — when day and night are of equal length — the Sun rises directly in the east and sets directly in the west. The changing location of the Sun on the horizon is due to Earth’s axial tilt as it orbits the Sun. In temperate regions of Earth, the Sun’s height above the horizon at noon is at its highest and lowest points in the sky on the summer and winter solstices respectively.
Credit: Marcella Giulia Pace/IAU OAE (CC BY 4.0)

Glossary Terms: Equinox , Solstice , Summer Solstice , Sun Path (Day Arc) , Winter Solstice
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 ( image 11.49 MB)

H-alpha image of the Sun's chromosphere

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Caption: This false-color image was captured with a 10-cm telescope at the Big Bear Solar Observatory (BBSO) in the United States in July 2002. It depicts the full disk of the Sun using the H-alpha emission line of hydrogen. When observed in this spectral line, the Sun's chromosphere appears particularly prominent due to hydrogen atoms emitting light at the specific wavelength. This emission produces a distinctive red color, making features such as spicules (jets of plasma that look hair-like) and plage (bright patches in the chromosphere) highly visible. Several small solar prominences can be seen protruding from the edge of the solar disk. When prominences (also known as filaments) cross the face of the disk they appear as dark threads caused by the cooler material in the prominence absorbing light. The chromosphere is also visible in the violet part of the solar spectrum due to ionized calcium showing emissions in these wavelengths.
Credit: Big Bear Solar Observatory (BBSO)/New Jersey Institut of Technology (NJIT)
Credit Link

Glossary Terms: Chromosphere , Solar Prominence , Sun , Spectral Line
Categories: The Sun

License: Public Domain Public Domain icons

File ( image 2.82 MB)

Winter Haloes, by Thomas Gigl, Germany

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Created for the OAE

Caption: Second place in the 2021 IAU OAE Astrophotography Contest, category Sun/Moon haloes. Captured in Jochberg located in the famous Austrian ski-region of Tirol, this image shows multiple features related to ice halos, which are a more common appearance around the sun, due to its brightness, than the moon. External and internal reflection of sun rays from ice crystal faces and within different types of ice crystals lead to these halo related phenomena. The 22° halo encircles the sun, with two bright spots at the edge called Sundogs, Parhelia or Mock Suns observed to the left and right at the same height as the sun. The horizontal white band called the parhelic circle, named after the sun god Helios, passes through the sun and the Sundogs at the same angular elevation. An Upper tangent arc, a suncave parry arc and a lower tangent arc are also seen touching the top and bottom of the 22° halo. An upside down rainbow like arc or the circumzenithal arc is seen touching the bright supralateral arc, both of which are less frequently observed.
Credit: Thomas Gigl/IAU OAE

Glossary Terms: Sun , Halo
Categories: Naked Eye Astronomy , The Sun

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 10.36 MB)

High-resolution image of the surface of the Sun

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Caption: This high-resolution image of a small portion of the outermost visible "surface" of the Sun (the photosphere) covers an area 36,500 by 36,500 km. It was one of the first images taken by the Daniel K. Inouye Solar Telescope, as part of the telescope's Science Verification Phase. Each of the cells that are visible is about the size of the US state Texas, or of France, or of Afghanistan, or of Somalia. In the brighter centers of these cells, plasma from the underlying regions rises to the surface, cools off, and then sinks down again at the location of the darker lanes delineating the cells. In these dark lanes we can also see the tiny, bright markers of magnetic fields.
Credit: NSO/NSF/AURA
Credit Link

Glossary Terms: Photosphere , Granulation
Categories: The Sun

License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons

File ( image 17.04 MB)