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Astro Bob: Aurora on Christmas night?

The aurora may stop by on Thursday night, Dec. 23, and again on Christmas. Check here for the latest forecast.

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During a minor G1 storm, pictured here, the aurora shimmers in the lower third of the sky. Sometimes you'll see just a single arc, but often the arc will break up into a series of faint, parallel rays. Contributed / Bob King
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Earlier this week, I described about how busy the sun was with sunspots. Five groups freckled the disk at the time. That number has since swelled to nine . Flares within some of those groups produced several modest coronal mass ejections (CMEs). These, coupled with a stream of material from a repeat coronal hole, mean we might see a minor auroral display Thursday, Dec. 23. Space weather experts predict a (G1) geomagnetic storm between about 9 p.m. and 1 a.m. CST.

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Look at all those sunspots! Nine different groups dot the sun's face Thursday, Dec. 23. Contributed / NASA, SDO

A separate CME that occurred Dec. 21 will arrive on Christmas and could also spark a small northern lights show. On the 23rd, the waning moon rises around 9 p.m. local time. Cross your fingers it won't overwhelm any aurora that may turn up. Christmas night will be better, with the moon out of the picture until after 11 p.m.

The last good, mid-latitude aurora occurred at the beginning of November with a spectacular all-sky display in the early morning. Any aurora we may see in the next few nights isn't expected to be as overwhelming, although you can never be sure. That's why it pays to be on the alert. Watch for a bright arc and perhaps a few delicate pillars across the bottom half of the northern sky in the coming nights.

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With this map and a little help from Orion's Belt see if you can spot all eight bright winter stars across six constellations the next clear night. The red outlines mark the official borders of each constellation. Contributed / Stellarium

While you wait, have a look around. The faint fall constellations in the southern and western sky are moving out to make way for the bright carpet of stars that accompany Orion. The three stars in a row that define his belt make an the ideal launching pad to track down winter's brightest luminaries. Above and below the trio you'll find Betelgeuse and Rigel. Extend a line through the belt upward to Aldebaran and down to the left to Sirius. From Sirius, swing over to Procyon and left to Castor and Pollux in Gemini. Twinkly Capella in the pentagon of Auriga shines above them all.

No other part of the northern hemisphere sky hosts so many first magnitude or brighter stars — eight in all. The red outlines on the map mark the official boundaries of the constellations, which were set back in 1930. Before that, no one agreed exactly where one constellation began and another ended. Unlike political borders, there've been no disputes or "sky grabs" since astronomers laid down the law. Peace and harmony rule in the heavens.

Merry Christmas and happy seasonal celebrations!

"Astro" Bob King is a freelance writer for the Duluth News Tribune. Read more of his work at duluthnewstribune.com/astrobob .

"Astro" Bob King is a freelance writer and retired photographer for the Duluth News Tribune.
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