From EarthSky: “Milky Way spins across the sky”

1

EarthSky

April 16, 2018
Deborah Byrd


This composite – centered on celestial south – is made of images taken hourly from outside the dome of the Anglo-Australian Telescope at Siding Spring Observatory.

1
Composite image by Christian Sasse.

Christian Sasse emailed EarthSky on April 11, 2018, from Australia’s Siding Spring Observatory and wrote:

“A spectacular night at the Anglo-Australian Telescope (3.9-meter [13-foot] mirror). This composite – made of images taken every hour from 7 p.m. until midnight – shows the apparent movement of the Milky Way across the sky. See Jupiter on the left, leaving a discrete trail as it moves towards the dome until midnight. Top is location of the celestial South Pole.”


AAO Anglo Australian Telescope near Siding Spring, New South Wales, Australia, Altitude 1,100 m (3,600 ft)

Siding Spring Mountain with Anglo-Australian Telescope dome visible near centre of image at an altitude of 1,165 m (3,822 ft)

As you can see, Christian has a novel approach to acquiring photographic images of star trails. His images have been featured in National Geographic and Nature. His Ph.D. in optics has helped shape his photography. You can visit him on his Facebook page, or on YouTube, or on Twitter (@sassephoto).

3
Article by Christian Sasse, originally published at his blog, The Cosmic Clock.

The Earth rotates or spins on its axis about every 24 hours, causing an apparent movement of the stars overhead by about one-quarter of a degree per minute. If we leave a camera in a fixed position and point upwards, open the shutter in bulb mode and let the Earth rotate under the stars, we will create an image with star trails. Similarly we could take shorter exposures and superimpose (stack) the images with image processing software.

Most images of star trails taken in the Northern Hemisphere show a pattern similar to the one below taken in Arches National Park, Utah, in spring of 2016.

4
Star trails at Arches National Park via Christian Sasse

Bottom line: Milky Way composite image by Christian Sasse.

Read more about Christian Sasse’s photographic process: A novel approach to star trails

See the full article here .

Please help promote STEM in your local schools.

STEM Icon

Stem Education Coalition

Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.