Astronomy Picture of the Day [1]Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2020 April 17 [2]See Explanation. Clicking on the picture will download the highest resolution version available. The Windmill and the Star Trails Image Credit & [3]Copyright: [4]Antonio Gonzalez Explanation: Stars can't turn these old wooden arms, but it does look like they might in this scene [5]from a rotating planet. The well-composed night skyscape was recorded from Garafia, a municipality on the island of La Palma, Canary Islands, [6]planet Earth. The center of the once working windmill, retired since 1953, is lined-up with the [7]north celestial pole, the planet's rotation axis projected on to the northern sky. From a camera fixed to a tripod, the star trails are a reflection of the planet's rotation traced in a digital composite of 39 sequential exposures each 25 seconds long. Brought out by highlighting the final exposure in the sequence, the stars themselves appear at the ends of their short concentric arcs. A faint band of winter's Milky Way and even a diffuse glow from our neighboring Andromeda Galaxy also shine [8]in the night. Tomorrow's picture: light-weekend __________________________________________________________________ [9]< | [10]Archive | [11]Submissions | [12]Index | [13]Search | [14]Calendar | [15]RSS | [16]Education | [17]About APOD | [18]Discuss | [19]> __________________________________________________________________ Authors & editors: [20]Robert Nemiroff ([21]MTU) & [22]Jerry Bonnell ([23]UMCP) NASA Official: Phillip Newman [24]Specific rights apply. [25]NASA Web Privacy Policy and Important Notices A service of: [26]ASD at [27]NASA / [28]GSFC & [29]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2004/WindmillStarTrails.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. mailto:%20astrojagh%20[at]%20gmail%20[dot]%20com 5. https://www.nasa.gov/content/earth-day-2020 6. https://earthobservatory.nasa.gov/images/81421/trailing-the-canaries 7. https://apod.nasa.gov/apod/ap131023.html 8. https://apod.nasa.gov/apod/ap150110.html 9. https://apod.nasa.gov/apod/ap200416.html 10. https://apod.nasa.gov/apod/archivepix.html 11. https://apod.nasa.gov/apod/lib/apsubmit2015.html 12. https://apod.nasa.gov/apod/lib/aptree.html 13. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 14. https://apod.nasa.gov/apod/calendar/allyears.html 15. https://apod.nasa.gov/apod.rss 16. https://apod.nasa.gov/apod/lib/edlinks.html 17. https://apod.nasa.gov/apod/lib/about_apod.html 18. http://asterisk.apod.com/discuss_apod.php?date=200417 19. https://apod.nasa.gov/apod/ap200418.html 20. http://www.phy.mtu.edu/faculty/Nemiroff.html 21. http://www.phy.mtu.edu/ 22. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 23. http://www.astro.umd.edu/ 24. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 25. https://www.nasa.gov/about/highlights/HP_Privacy.html 26. https://astrophysics.gsfc.nasa.gov/ 27. https://www.nasa.gov/ 28. https://www.nasa.gov/centers/goddard/ 29. http://www.mtu.edu/