by APOD Robot » Sat Jul 16, 2016 4:10 am
The North Celestial Tower
Explanation: If you climbed to the top of this 13th century stone tower, it looks like you could reach out and touch the
North Celestial Pole, the point at the center of all the star trail arcs.
The well-composed image with scattered meteor streaks was recorded over a period of five and half hours as a series of 45 second long exposures spanning the dark of the night on July 7/8. The exposures were made with a digital camera fixed to a tripod near Marathon, Greece,
planet Earth. Of course, the graceful star trails reflect the Earth's
daily rotation around its axis. By extension, the axis of rotation leads to the center of the concentric arcs
in the night sky. Convenient for northern hemisphere night sky photographers and celestial navigators alike, the
bright star Polaris is very close to the North Celestial Pole and so makes the short bright trail in the tower's central gap.
[/b]
[url=http://apod.nasa.gov/apod/ap160716.html][img]http://apod.nasa.gov/apod/calendar/S_160716.jpg[/img] [size=150]The North Celestial Tower[/size][/url]
[b] Explanation: [/b] If you climbed to the top of this 13th century stone tower, it looks like you could reach out and touch the [url=http://apod.nasa.gov/apod/ap120712.html]North Celestial Pole[/url], the point at the center of all the star trail arcs. [url=http://www.perseus.gr/Astro-Star-Trails-Tower-Marathon-Oinoe-2016.htm]The well-composed image[/url] with scattered meteor streaks was recorded over a period of five and half hours as a series of 45 second long exposures spanning the dark of the night on July 7/8. The exposures were made with a digital camera fixed to a tripod near Marathon, Greece, [url=http://epic.gsfc.nasa.gov/]planet Earth[/url]. Of course, the graceful star trails reflect the Earth's [url=http://apod.nasa.gov/apod/ap120802.html]daily rotation[/url] around its axis. By extension, the axis of rotation leads to the center of the concentric arcs [url=http://apod.nasa.gov/apod/ap130920.html]in the night sky[/url]. Convenient for northern hemisphere night sky photographers and celestial navigators alike, the [url=http://apod.nasa.gov/apod/ap110514.html]bright star Polaris[/url] is very close to the North Celestial Pole and so makes the short bright trail in the tower's central gap.
[b][table][tr][td=left][url=http://asterisk.apod.com/discuss_apod.php?date=160715]<< Previous APOD[/url][/td] [td=center][url=http://asterisk.apod.com/view_retro.php?date=0716]This Day in APOD[/url][/td] [td=right][url=http://asterisk.apod.com/discuss_apod.php?date=160717]Next APOD >>[/url][/td][/tr][/table][/b]