Transit of Jupiter from Titan in 2080? Options

[algorimancer]

I would bet that we'll have had a few rovers on Titan by 2080, and perhaps on Triton as well. Maybe something will still be functional and able to send back a pic. Hopefully no clouds on Titan.

[dvandorn]

Saturn transiting the Sun looks like some sort of symbol for the Freemasons.

Oh, dear, he's found us out... I suppose we'll have to kill him now...



-the other Doug

[yaohua2000]

But Wikipedia says it will be a near miss.

http://en.wikipedia.org/wiki/Transit_of_Ju...m_outer_planets

[ugordan]

I would bet that we'll have had a few rovers on Titan by 2080, and perhaps on Triton as well. Maybe something will still be functional and able to send back a pic. Hopefully no clouds on Titan.

Whether or not we wind up having a rover there and then it won't make much difference. The Sun is 3.5 arc minutes across from Saturn and 1.1 arc min across from Neptune. No rover camera is going to have that kind of resolution to resolve the Sun as anything larger than a speck of light, let alone resolve Jupiter or Saturn transiting it. A powerful orbiter camera might do the trick, but then again we wouldn't want to point it at the Sun, would we?

[tasp]

So sometime around this interesting event Jupiter and Saturn would appear rather close to each other as seen from earth.

Would they be uniquely close for this time frame (2000 to 2100) ?

[algorimancer]

Whether or not we wind up having a rover there and then it won't make much difference. The Sun is 3.5 arc minutes across from Saturn and 1.1 arc min across from Neptune. No rover camera is going to have that kind of resolution to resolve the Sun as anything larger than a speck of light, let alone resolve Jupiter or Saturn transiting it. A powerful orbiter camera might do the trick, but then again we wouldn't want to point it at the Sun, would we?

Consider that MER routinely takes pictures of the sun with its pancam for rover localization, using a solar filter. It also images Deimos and Phobos. MSL will do the same, but with a better camera (1200X1200 pixels) including a 10X zoom capability (6 degrees FOV). A quick back-of-envelope calculation ... 6 degrees= 360 arc minutes divided by 1200 pixels = 0.3 arc minutes per pixel, so 3.5 arc minutes spans 11 pixels, 1.1 arc minutes spans 3 pixels ... suggests that MSL's camera would clearly resolve the sun from Saturn, and should have no serious difficulty resolving the disc of Jupiter. The sun is a little more challenging from Neptune, but still clearly resolvable (Saturn less so). I would be surprised if imaging technology didn't radically improve over the next several decades, so I feel confident that if a rover is present, the image can be acquired.

[ugordan]

Good points on MSL, I underestimated its camera. Still, the Neptune scenario stands as very difficult. One must also take into consideration telecom difficulties when dealing with Saturn or, worse, Neptune. Mars is practically at our back door, but these worlds are several (tens) of AU distant. It's gonna be hard to rationalize such super-cameras for Triton (heck, even Titan) when you take into consideration the bandwidth they require. I'm sure there'll be some advances in telecomunications over the next decades (optics?) and even image compression but it's questionable whether 100s of kilobits at Neptune will be feasible. Of course, I'm pulling figures out of thin air so I could be wrong again.

[tuvas]

Quite a different date for me though 29 May 2061 13:00 UTC mid transit.

Now THAT is a sight for sore eyes! Planetary transists for the most part seem fairly boring, but to see Saturn, THAT would be amazing;-)

[djellison]

And scienticially interesting as well.

Doug

[As old as Voyage...]

An even more spectacular view of a Saturn transit will occur on (or around) 08 April 2669 when Saturn transits the Sun as seen from Uranus and its moons.

Of course a transit of Saturn (or any other planet) can be seen at any time simply by being high above the planet's night side, but that's the transit equivalent of shooting fish in a barrel. To see such an event from another celestial body is the real prize.

Pity the great ones don't occur too frequently. The next reasonably good transit is that of Earth as seen from Jupiter on 09 July 2008. From Earth Jupiter will be seen as a totally full disc, good stuff if you wanna measure its oblateness.

[tuvas]

An even more spectacular view of a Saturn transit will occur on (or around) 08 April 2669 when Saturn transits the Sun as seen from Uranus and its moons.

Of course a transit of Saturn (or any other planet) can be seen at any time simply by being high above the planet's night side, but that's the transit equivalent of shooting fish in a barrel. To see such an event from another celestial body is the real prize.

Pity the great ones don't occur too frequently. The next reasonably good transit is that of Earth as seen from Jupiter on 09 July 2008. From Earth Jupiter will be seen as a totally full disc, good stuff if you wanna measure its oblateness.

Sure, I'll be sure to have myself cyrogenically frozen to witness that transit. Hmmm... Maybe not on second thought...

The real fun ones haven't been mentioned yet, those of planet-planet transitions, imagine seeing Venus appear to pass in front of Jupiter. THAT would be cool, at least to me.

[claurel]

Quite a different date for me though 29 May 2061 13:00 UTC mid transit.

I think Titan transits almost right across the center of the sun just afterwards as well (but I can't see it as I'm still on the old version, waiting for the power in Seattle. Just have to track Titan and imagine it at the centre of the screen )

This new version of Celestia has a bug fix that makes moons visible during transits:

http://www.shatters.net/~claurel/celestia/...2-1.5.0pre2.exe

It's a prerelease, so you probably don't want to blow away your current installation. If you want high precision, this version can also use JPL DE406 ephemerides for the planets and Moon (see http://en.wikibooks.org/wiki/Celestia/JPL_Ephemerides). But, even the VSOP87 orbital theory that Celestia uses by default (and likely Starry Night too) has enough terms to calculate planet positions to arcsecond accuracy. That should be more than adequate for viewing transits.

I'm getting a sense of how difficult it would be to observe the transit of a moon--even Ganymede is a barely visible black fleck. The Ganymede transit is an interesting one though. Seen from Titan, it actually appears to be a double transit, completely exiting the Sun's disc and then crossing again in the other direction.

--Chris

[jamescanvin]

Cheers Chris, although I'm on a Mac so have very little use for strange .exe files Glad it's fixed in the upcoming version though, these multiple transits of planets and moons is an awesome sight. Your right, very difficult to observe in real life, (not least getting to Titan, and living to 103) but that's why we have Celestia.

James

[scalbers]

The real fun ones haven't been mentioned yet, those of planet-planet transitions, imagine seeing Venus appear to pass in front of Jupiter. THAT would be cool, at least to me.

You might be interested in the URL shown below, that discusses and extends my 1979 Sky and Telescope article on mutual planetary occultations...

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

[jsheff]

Sure, I'll be sure to have myself cyrogenically frozen to witness that transit. Hmmm... Maybe not on second thought...

The real fun ones haven't been mentioned yet, those of planet-planet transitions, imagine seeing Venus appear to pass in front of Jupiter. THAT would be cool, at least to me.

I came across one of those; what's more, most of us will be alive when it happens. Unfortunately Cassini will probably be long gone; maybe a Titan Explorer will see it.

On January 12, 2032, Earth will partially occult Venus as seen from Saturn. Here's an image I made in Celestia, depicting the event as seen from Enceladus. There are places near Saturn space where the occultation is total, but I don't think that will be visible from any of the moons. More to follow ...

John Sheff
Cambridge, MA

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