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View Full Version : Planetary occultation from Mars?



Manchurian Taikonaut
2008-Dec-08, 02:50 PM
One object in sky sky appears to hide another, appearing to pass in front of or behind the other. Yes maybe we have viewed lunar occultations since ancient times but occultations of planets from our view on Earth are a rare event. One was in 1818, Venus passed in front of Jupiter but nobody saw it (was our whole planet cloudy that day?). Galileo could have seen something in 1613, but he only observed Neptune a few days late as a background star near the planet Jupiter. My gut feeling is Mars is the better viewing site for event since Earth is bigger object and Mars is closer to Jupiter. I have no idea how to calculate occultations from another body. Is there any free program I can download to check for occultations from another planet and does this program gives the user a view as if you were on the surface? Or is there any software you would recommend buying?

thanks in advance

Romanus
2008-Dec-09, 03:30 AM
Celestia sounds like a sure bet, though you'll have to talk to some of the other knowledgeable chums around who actually know how to use it. ;)

Manchurian Taikonaut
2008-Dec-11, 03:21 PM
Thanks I'll try Celestia

PS
I found a great site

http://www.go.ednet.ns.ca/~larry/planets/occltlst.htm

Centaur
2008-Dec-11, 11:35 PM
One object in sky sky appears to hide another, appearing to pass in front of or behind the other. Yes maybe we have viewed lunar occultations since ancient times but occultations of planets from our view on Earth are a rare event. One was in 1818, Venus passed in front of Jupiter but nobody saw it (was our whole planet cloudy that day?). Galileo could have seen something in 1613, but he only observed Neptune a few days late as a background star near the planet Jupiter. My gut feeling is Mars is the better viewing site for event since Earth is bigger object and Mars is closer to Jupiter. I have no idea how to calculate occultations from another body. Is there any free program I can download to check for occultations from another planet and does this program gives the user a view as if you were on the surface? Or is there any software you would recommend buying?


Jean Meeus in his Mathematical Astronomy Morsels III (3rd of a series of 4) includes tables of mutual planetary occultations/transits as viewed from other planets.

According to Meeus, the last mutual planetary occultation or transit seen from Mars occurred on 1943 NOV 28 when Earth appeared to partially occult Mercury. The next event will occur on 2022 NOV 29 when Mercury will appear to totally transit Jupiter.

When an object with a larger apparent angular diameter passes in front of a smaller one, it’s called an occultation. The reverse is referred to as a transit.

The most likely reason the no one reported observing the 1818 transit of Venus across Jupiter is that predictive methods at the time were not accurate enough for anyone to become prepared. Additionally, the pair was only 16 from the Sun. The only recorded observation of a mutual planetary occultation or transit since the invention of the telescope occurred in 1737 when Venus occulted Mercury. John Bevis at the Royal Greenwich Observatory saw the pair prior to the occultation and after Venus fully covered Mercury. Clouds intervened when the occultation was actually taking place. Seen below is a graphic I created to show what Bevis would have seen shortly before the pair set. Mercury was actually behind Venus, but I’ve placed it in front as though seen with X-ray vision.


http://www.curtrenz.com/VenusMercury.JPG