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APOD: 2025 September 13 Á Star Trails over One Mile Radio Telescope
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Credit & Copyright: Joao Yordanov Serralheiro
Explanation:
The steerable 60 foot diameter dish antenna of the
One-Mile Telescope at
Mullard
Radio Astronomy Observatory,
Cambridge, UK, is
pointing
skyward
in this evocative night-skyscape.
To capture the dramatic scene, consecutive 30 second exposures
were recorded over a period of 90 minutes.
Combined, the exposures reveal a background of gracefully arcing
star trails that
reflect planet Earth's daily rotation on
its axis.
The North Celestial Pole,
the extension of
Earth's axis of rotation into space, points near Polaris,
the North Star.
That's the bright star that creates the short trail
near the center of the concentric arcs.
But the
historic One-Mile Telescope
array also relied on planet Earth's rotation to operate.
Exploring the universe at radio wavelengths,
it was the first radio telescope to use
Earth-rotation aperture synthesis.
That technique
uses the rotation of the Earth to change the relative orientation of
the telescope array and celestial radio sources
to create
radio maps of the sky
at a resolution better than that of the human eye.
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NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: star trail
Publications with words: star trail
See also: