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.
2012 September 21
Explanation: September's equinox arrives tomorrow as the Sun crosses the celestial equator heading south. The event marks the astronomical beginning of spring in the southern hemisphere and autumn in the north. And though the connection is still puzzling, the equinox seasons bring an increase in geomagnetic storms. So as northern nights grow longer, the equinox also heralds the arrival of a good season for aurora hunters. Recorded on September 20, these colourful northern lights were captured with camera and wide-angle lens near the Norwegian Sea coast outside Tromsø in Northern Norway. Shining at altitudes of 100 kilometres or so, the aurora rays are parallel, but perspective makes them appear to radiate from a vanishing point behind the silhouetted pine tree. Stars in this enchanting northern night include Polaris above and right of the tree top, and yellowish giant stars Shedar (Alpha Cassiopiae) to the left and Kochab (Beta Ursae Minoris) to the right. Bright Altair shines through the greenish auroral curtain at the lower left of the scene.
Authors & editors:
Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
A service of: ASD at NASA / GSFC
& Michigan Tech. U.