by Anthony Barreiro » Sat Dec 14, 2013 7:02 pm
Anthony Barreiro wrote:georgeliv wrote:The apod image of Jupiter in Taurus is almost certainly from 2011.
2012 was my 35th year of following Jupiter; going though nearly exactly 3 orbits back in the feet of Gemini.
My planetarium software, sky safari, agrees with the apod caption. On December 14, 2012, Jupiter was 2 degrees north of Epsilon Tauri, the bull's dimmer eye, as seen in the picture. On December 14, 2011, Jupiter was 7 degrees northeast of Alpha Piscium, the knot tying the two fish together. I think you might have gotten off by a year here or there. 36 years is a long time!
This has been stuck in my mind since yesterday. Planetarium software is very helpful, but what did people do before we had electronic digital computers? Well, we know that Jupiter takes about 12 years to transit through the zodiac, traveling an average of about 30 degrees of ecliptic longitude (or one tropical zodiac sign) per year. By looking up at the sky we see that Jupiter is currently conjunct Wasat, Delta Geminorum, which a star atlas shows is about ecliptic longitude 110 degrees. Therefore one year ago Jupiter would have been about ecliptic longitude 80 degrees, between the horns of Taurus, Beta and Zeta Tauri. This is further east than the location the software shows for Jupiter on December 14, 2012, but much closer than 50 degrees ecliptic longitude, east of the eastern head of Pisces and the stars of Aries, where it would have been two years ago, on December 14, 2011. The planetarium software shows that on December 14, 2011 Jupiter was actually closer to Alresha, Alpha Piscium, about 30 degrees ecliptic longitude.
Now I need to figure out why Jupiter has been traveling about 40 degrees of ecliptic longitude per year for the past two years, rather than 30 degrees per year. Hmm, Kepler's laws of planetary motion? Perhaps Jupiter is close to perihelion and therefore traveling faster than average? Okay, I cheated here and did
a quick web search which showed that Jupiter was in fact at perihelion on March 18, 2011.
But the general point is that a naked-eye observation, one basic piece of memorized information, and a simple star atlas gives a good enough double check of Jupiter's location during the past couple of years. This could be useful if all our electronics are fried by an electromagnetic pulse from a nearby supernova.
[quote="Anthony Barreiro"][quote="georgeliv"]The apod image of Jupiter in Taurus is almost certainly from 2011.
2012 was my 35th year of following Jupiter; going though nearly exactly 3 orbits back in the feet of Gemini.[/quote]
My planetarium software, sky safari, agrees with the apod caption. On December 14, 2012, Jupiter was 2 degrees north of Epsilon Tauri, the bull's dimmer eye, as seen in the picture. On December 14, 2011, Jupiter was 7 degrees northeast of Alpha Piscium, the knot tying the two fish together. I think you might have gotten off by a year here or there. 36 years is a long time![/quote]
This has been stuck in my mind since yesterday. Planetarium software is very helpful, but what did people do before we had electronic digital computers? Well, we know that Jupiter takes about 12 years to transit through the zodiac, traveling an average of about 30 degrees of ecliptic longitude (or one tropical zodiac sign) per year. By looking up at the sky we see that Jupiter is currently conjunct Wasat, Delta Geminorum, which a star atlas shows is about ecliptic longitude 110 degrees. Therefore one year ago Jupiter would have been about ecliptic longitude 80 degrees, between the horns of Taurus, Beta and Zeta Tauri. This is further east than the location the software shows for Jupiter on December 14, 2012, but much closer than 50 degrees ecliptic longitude, east of the eastern head of Pisces and the stars of Aries, where it would have been two years ago, on December 14, 2011. The planetarium software shows that on December 14, 2011 Jupiter was actually closer to Alresha, Alpha Piscium, about 30 degrees ecliptic longitude.
Now I need to figure out why Jupiter has been traveling about 40 degrees of ecliptic longitude per year for the past two years, rather than 30 degrees per year. Hmm, Kepler's laws of planetary motion? Perhaps Jupiter is close to perihelion and therefore traveling faster than average? Okay, I cheated here and did [url=http://answers.yahoo.com/question/index?qid=20110221111450AAvF2au]a quick web search[/url] which showed that Jupiter was in fact at perihelion on March 18, 2011.
But the general point is that a naked-eye observation, one basic piece of memorized information, and a simple star atlas gives a good enough double check of Jupiter's location during the past couple of years. This could be useful if all our electronics are fried by an electromagnetic pulse from a nearby supernova. :ssmile: