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Ice and Stone


Comet of the Week: ISON C/2012 S1

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Special Topic: Close Asteroidal Encounters

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Comet of the Week: 29P/Schwassmann-Wachmann 1 1927j

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Special Topic: Comets and Meteor Showers

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NOVEMBER 22, 2020: The Apollo-type asteroid (7753) 1988 XB will pass 0.066 AU from Earth. The best visibility will be next week when it travels west-northwestward through Leo, Cancer, and Gemini and will be 15th magnitude. Close approaches by near-Earth asteroids are the subject of this week’s “Special Topics” presentation.   NOVEMBER 25, 2005: JAXA’s Hayabusa …

Perihelion: 2013 November 28.78, q = 0.012 AU  I mentioned in the “Special Topics” presentation on “Great Comets” that such objects come by about once a decade, on average. Comet NEOWISE C/2020 F3, which appeared back in July, could perhaps be considered a borderline “Great” comet, but prior to that, the last “Great Comet” for those of …

In the Week 2 “Special Topics” presentation I discussed the history and recognition of near-Earth asteroids and described some of the early observed encounters by these objects. What could perhaps be considered the most remarkable of these asteroids was a 10th-magnitude fast-moving object discovered on October 28, 1937, by Karl Reinmuth at Heidelberg Observatory in …

NOVEMBER 15, 1927: Arnold Schwassmann and Arno Wachmann at Hamburg Observatory in Bergedorf, Germany, discover a very unusual comet, 29P/Schwassmann-Wachmann 1, that travels entirely between the orbits of Jupiter and Saturn and that undergoes repeated outbursts at irregular intervals. It is this week’s “Comet of the Week.”  NOVEMBER 15, 2016: Polish astronomers Filip Berski and …

Perihelion: 1925 May 7.84, q = 5.475 AU  One of the most unusual and remarkable comets that we know about was discovered just a little less than a century ago, when on November 15, 1927, the duo of Arnold Schwassmann and Arno Wachmann at Hamburg Observatory in Bergedorf, Germany, found it on photographs as it was …

I first began to show an interest in astronomy when I was 6 years old, although my interests shifted between astronomy and various other scientific fields over the next few years. My father was an early riser, and one morning when I was 8 he was engaged in his normal morning routine when he noticed that …