Big Dipper Over the Mono Lake

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. The Big Dipper asterism gracefully moves above the otherworldly tufa formations of Mono Lake, California. The time-lapse captures the Big Dipper’s movement across the northern horizon until its inferior conjunction. At Mono Lake’s latitude (+38°), the stars of the Big Dipper remain circumpolar, except for Alkaid. The North Star sits 38° above the horizon, just outside the field of view in the top right. The lunar illumination bathes the landscape in a soft glow, gradually fading as the Moon sets, cloaking the scene in darkness.
Credit: Fabrizio Melandri/IAU OAE (CC BY 4.0)

Glossary Terms: Big Dipper , Celestial Pole , Celestial Sphere , Circumpolar Stars , Earth's Rotation , Polaris
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 65.30 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)

Stone Star Circles, Startrails above Stonehenge, by Till Credner, Germany

image
Created for the OAE

Caption: Second place in the IAU OAE Astrophotography Contest, category Star trails. Astronomy is one of the oldest (if not the oldest) of the sciences, and as such has connection to various cultures over millennia. This image in a way conveys this relationship by being contextualised in Stonehenge. There is much research into what astronomers call archeoastronomy sites, and how they connect to the sky (for example, seasons, phases of the moon and much more). Civilizations across time and from all over the world have their own views and interpretations of what they see in the sky, and this has been tied not only to culture but also to the people’s day-to-day and seasonal activities. The “concentric circles” which are often referred to as “star trails”, are the result of the apparent motion of the sky, which is in reality due to the rotation of the Earth on its axis. The small dot appearing towards the top center of the image is Polaris – The North or Pole Star. Polaris is only visible to observers in the Northern latitudes. The height of the Pole Star can be used to infer the observer’s actual latitude. Stonehenge is located at around 51° North. This image is taken from one of the most notable ancient sites in the world, brings us back in time, and makes us wonder about the stories told by the people that lived in that place many millennia ago.
Credit: Till Credner/IAU OAE

Glossary Terms: Circumpolar Stars , Star Trail
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 1.26 MB)

Half day exposure to the north star, by Fabrizio Melandri, Italy

image
Created for the OAE

Caption: First place in the IAU OAE Astrophotography Contest, category Star trails. This star trail image shows the apparent movement of the stars in the night sky, which results from the Earth’s rotation around its polar axis. The trees in the foreground serve as an anchor as we turn with the Earth. The bright white semi-circle in the center of the image is the North (Pole) star – Polaris, which is located very close to the North Celestial Pole. One way to imagine that the Earth is at center of hollow crystal sphere, and the stars are embedded on this sphere, as the Earth spins on its axis, an observer on Earth sees the stars rising and setting, following an arc, because the horizon prevents the observer from the full arc for stars that are further away from the Celestial Pole. The North Celestial Pole (and its opposite the South Celestial Pole) is essentially formed by extending the line of the Earth’s axis. Capturing this image requires the photographer to take a long exposure with the camera on a tripod and pointing towards the Pole Star (North Hemisphere). In the Southern Hemisphere there is no star as close as Polaris is to the Celestial Pole, so the position of the South Celestial Pole is found using the South Cross and Pointer Stars (Alpha and Beta Centauri). Although overall the image has a slight blue tint, it does capture the varying colours of stars, it is easy to distinguish between the higher temperature blue stars and the lower temperature of the whitish stars, and even lower temperature reddish stars. The reason for this variation in colour is because higher temperature stars emit more in shorter wavelengths (bluer), compared to lower temperature stars which emit in longer wavelengths (redder).
Credit: Fabrizio Melandri/IAU OAE

Glossary Terms: Circumpolar Stars , Star Trail
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 6.11 MB)

The Big Dipper in the Polar Night

video
Created for the OAE

Caption: Third place winner in the 2023 IAU OAE Astrophotography Contest, category of Time-lapses of rotation of Big Dipper or Southern Cross. Step into the cosmic theatre of Iceland’s northern skies in this time-lapse where the illustrious Big Dipper commands attention, tracing an almost complete circle around Polaris — an exquisite sight that is not visible from mid-latitudes. This time-lapse, captured through fisheye lenses, reveals the timeless choreography of the Big Dipper, vividly illustrating its celestial waltz. Amidst this spectacle, the Arctic night reveals its grandeur, painting a panoramic canvas that showcases not just the celestial journey of this iconic asterism but also the ethereal dance of the Northern Lights. In this breathtaking tapestry, the Big Dipper takes centre stage against the mesmerising backdrop of the Icelandic nightscape, adorned by the vibrant hues of the Aurora Borealis.
Credit: Stephanie Ziyi Ye/IAU OAE (CC BY 4.0)

Glossary Terms: Aurora , Big Dipper , Polar Night , Aurora Borealis
Categories: Naked Eye Astronomy , Planet Earth
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 164.96 MB)