Printable Version of Topic

Click here to view this topic in its original format

Unmanned Spaceflight.com _ Saturn _ Transit of Jupiter from Titan in 2080?

Posted by: As old as Voyager Dec 17 2006, 05:45 PM

The Cassini spacecraft wasn't able to image the 13 January 2005 transit of Earth visible from Saturn but one of its successors may well be able to capture a view of one of the most spectacular transits of all, that of Jupiter.

I ran some calculations in 2004 and found that on the 19 May 2080 as seen from Titan (and its vicinity) Jupiter will transit the Sun. The underbelly of the giant planet will graze over the Sun’s northern tip creating an impressive 40.47 arc second dent in our star and blocking around four percent of its light.

Jupiter’s north may escape the Sun but it will be ringed by fire as sunlight is bent through its Hydrogen atmosphere towards Titan, giving valuable clues to its exact chemical composition.

This event is incredibly rare, having last occurred in 86 AD and after the 2080 event there will no repeat until the year 7541.

I used JPL's Solar System simulator to get an image of the event, but as it now only simulates up to 2025, I cannot reproduce the simulation.

Can anyone confirm that this event will occur from Titan on 19 May 2080?

Posted by: scalbers Dec 17 2006, 09:55 PM

This might be showable using Celestia...

Posted by: jamescanvin Dec 17 2006, 11:58 PM

QUOTE (scalbers @ Dec 18 2006, 08:55 AM) *
This might be showable using Celestia...


Yup.



Except that in Celestia this happens a day later on the 20th (starting around 13:00 UTC and ending 04:00 UTC on the 21st)

James

Posted by: As old as Voyager Dec 18 2006, 05:11 PM

Thanks James! That's great!

This rare Jupiter transit was written off as a near miss, and it is from the rest of Saturn's moons, but iit'll be quite a sight from Titan. Hmm...I'll be 103, so odds are these simulated pics will have to suffice!

Posted by: claurel Dec 18 2006, 06:51 PM

QUOTE (jamescanvin @ Dec 17 2006, 03:58 PM) *
Yup.

Except that in Celestia this happens a day later on the 20th (starting around 13:00 UTC and ending 04:00 UTC on the 21st)


Nice find . . . I'll have to figure out why Celestia is off by a day though. I'll see if it shows up on the right day when I switch from VSOP87 to the JPL DE406 ephemeris for the planets.

--Chris

Posted by: As old as Voyager Dec 18 2006, 08:49 PM

The image I got off JPL's Solar System Simulator shows mid transit at around 17.00 GMT on 19 May 2080. Any more info would be great as I've been meaning to get around to investigating this event further since Dec 2004 when I discovered it would occur.

Posted by: JRehling Dec 18 2006, 10:13 PM

QUOTE (As old as Voyager @ Dec 17 2006, 09:45 AM) *
north may escape the Sun but it will be ringed by fire as sunlight is bent through its Hydrogen atmosphere towards Titan, giving valuable clues to its exact chemical composition.


I doubt that sending something to Titan will be a cost-effective way to get information on the composition of Jupiter's atmosphere. But it will be a nice picture!

Posted by: jsheff Dec 19 2006, 06:24 AM

QUOTE (As old as Voyager @ Dec 18 2006, 03:49 PM) *
The image I got off JPL's Solar System Simulator shows mid transit at around 17.00 GMT on 19 May 2080. Any more info would be great as I've been meaning to get around to investigating this event further since Dec 2004 when I discovered it would occur.

I'm using Starry Night Pro 6, and I get the same answers as James.

Furthermore, can anyone verify the following?

Just as Jupiter is ending its transit, Ganymede appears (2080/05/21 3:43 UT) and it too begins a transit. That transit concludes at 22:20 UT on the 22nd. Meanwhile, Europa begins a transit at 17:12 UT, passes less than 3" from Ganymede (18:33 UT on 2080/05/21) while both are still on the Sun's disk (!), and leaves at 01:24 UT on the 22nd. I hope I'm not pushing the accuracy of this software past its reasonable limits...

- John Sheff
Cambridge, MA

Posted by: jamescanvin Dec 19 2006, 07:26 AM

QUOTE (claurel @ Dec 19 2006, 05:51 AM) *
Nice find . . . I'll have to figure out why Celestia is off by a day though. I'll see if it shows up on the right day when I switch from VSOP87 to the JPL DE406 ephemeris for the planets.

--Chris


Welcome to UMSF Chris, and can I take a moment to thank you for Celestia - totally awesome. smile.gif


QUOTE (jsheff @ Dec 19 2006, 05:24 PM) *
Just as Jupiter is ending its transit, Ganymede appears (2080/05/21 3:43 UT) and it too begins a transit. That transit concludes at 22:20 UT on the 22nd. Meanwhile, Europa begins a transit at 17:12 UT, passes less than 3" from Ganymede (18:33 UT on 2080/05/21) while both are still on the Sun's disk (!), and leaves at 01:24 UT on the 22nd. I hope I'm not pushing the accuracy of this software past its reasonable limits...


Ooh, nice find! Yup, Celestia gives the same (more or less I don't think the times quite match) here is a screenie.



And did you notice that Ganymede transits one way, just about crosses the suns limb to end the transit and then recrosses it and transits back the other way!!!

BTW Chris, when I do this all the moons of Jupiter disappear while Jupiter is within approx one Jupiter diameter of the sun so I miss a lot of the action. sad.gif (Although I am using an old version (1.3.2) atm so maybe that bug has already been fixed.)

James

Posted by: As old as Voyager Dec 19 2006, 05:52 PM

Thanks for the extra info on the transits by Jupiter's moons, I thought they may just clip the top of the Sun's disc and they do, great!

Posted by: As old as Voyager Dec 19 2006, 06:15 PM

Here's another transit to look out for and not as long to wait either!

On 16 June 2061 Saturn will transit the Sun as seen from Neptune. The 3.1 billion km distant saturn appears with its rings slightly open giving the impression of an 8 arc second wide eye inlaid onto the Sun.

Have a look with Celestia.

Posted by: claurel Dec 19 2006, 11:33 PM

QUOTE (jamescanvin @ Dec 18 2006, 11:26 PM) *
Welcome to UMSF Chris, and can I take a moment to thank you for Celestia - totally awesome. smile.gif
Ooh, nice find! Yup, Celestia gives the same (more or less I don't think the times quite match) here is a screenie.


Thanks. I've been lurking around here for quite a while now--aside from the Celestia forums, this is probably my favorite board to visit.

QUOTE
BTW Chris, when I do this all the moons of Jupiter disappear while Jupiter is within approx one Jupiter diameter of the sun so I miss a lot of the action. sad.gif (Although I am using an old version (1.3.2) atm so maybe that bug has already been fixed.)


Yes, that's a very old version. I'm working on 1.5.0 now, and that bug should be fixed. There are a *lot* of new features in 1.5.0 that will be of interest to UMSF members, including SPICE support. If there's an appropriate forum on UMSF, I'll post an update there soon . . . I'm still waiting for my electricity to be turned on again; it's been down since last Thursday due to the wind storm we had in Seattle.

--Chris

Posted by: jamescanvin Dec 20 2006, 12:24 AM

Thanks, now that's a transit!



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. rolleyes.gif Just have to track Titan and imagine it at the centre of the screen wink.gif )

James

Posted by: tasp Dec 20 2006, 03:00 AM

Just wait till the exo-planet hunters turn up a light curve for a transit like that!

blink.gif

Posted by: JRehling Dec 20 2006, 03:36 AM

[...]

Posted by: algorimancer Dec 20 2006, 03:45 AM

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.

Posted by: dvandorn Dec 20 2006, 06:10 AM

QUOTE (JRehling @ Dec 19 2006, 10:36 PM) *
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...

rolleyes.gif

-the other Doug

Posted by: yaohua2000 Dec 20 2006, 10:08 AM

But Wikipedia says it will be a near miss.

http://en.wikipedia.org/wiki/Transit_of_Jupiter_from_outer_planets

Posted by: ugordan Dec 20 2006, 10:22 AM

QUOTE (algorimancer @ Dec 20 2006, 04:45 AM) *
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?

Posted by: tasp Dec 20 2006, 03:08 PM

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) ?

Posted by: algorimancer Dec 20 2006, 03:59 PM

QUOTE (ugordan @ Dec 20 2006, 04:22 AM) *
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.

Posted by: ugordan Dec 20 2006, 05:55 PM

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.

Posted by: tuvas Dec 20 2006, 06:12 PM

QUOTE (jamescanvin @ Dec 19 2006, 05:24 PM) *
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;-)

Posted by: djellison Dec 20 2006, 06:22 PM

And scienticially interesting as well.

Doug

Posted by: As old as Voyager Dec 20 2006, 07:15 PM

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.

Posted by: tuvas Dec 20 2006, 07:23 PM

QUOTE (As old as Voyager @ Dec 20 2006, 12:15 PM) *
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.

Posted by: claurel Dec 21 2006, 09:58 AM

QUOTE (jamescanvin @ Dec 19 2006, 04:24 PM) *
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. rolleyes.gif Just have to track Titan and imagine it at the centre of the screen wink.gif )


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

http://www.shatters.net/~claurel/celestia/files/celestia-win32-1.5.0pre2.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

Posted by: jamescanvin Dec 21 2006, 09:50 PM

Cheers Chris, although I'm on a Mac so have very little use for strange .exe files wink.gif 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. smile.gif

James

Posted by: scalbers Dec 21 2006, 10:59 PM

QUOTE (tuvas @ Dec 20 2006, 07:23 PM) *
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

Posted by: jsheff Dec 28 2006, 07:46 PM

QUOTE (tuvas @ Dec 20 2006, 02:23 PM) *
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

 

Posted by: tuvas Dec 28 2006, 07:49 PM

QUOTE (jsheff @ Dec 28 2006, 12:46 PM) *
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


Personally I think a partial ocultation would be cooler than a full ocultation, but maybe that's just me...

Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)