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PostPosted: Wed, 14-10-15, 1:12 GMT 
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this folder was empty , but not any more

ftp://naif.jpl.nasa.gov/pub/naif/cosmographia/

a installer
ftp://naif.jpl.nasa.gov/pub/naif/cosmographia/packages/

SPICE kernels to add on
ftp://naif.jpl.nasa.gov/pub/naif/cosmographia/kernels/

right now just DAWN ( Vesta and Ceres )

and a user guide
ftp://naif.jpl.nasa.gov/pub/naif/cosmog ... sersguide/

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PostPosted: Wed, 14-10-15, 8:19 GMT 
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Since Chris Laurel's name is hard to find ;-) in the whole package I guess it has been "given to" or "sold to" NASA...The core Cosmographia is now distributed with another License (Apache II) and extensions were created by CALTECH under a US Government contract with NASA. The original code project has been archived (https://code.google.com/p/cosmographia/feeds) and is now ReadONLY. An export to the GitHub repository has taken place:

https://github.com/claurel/cosmographia

Activity there is close to zero, however, since >= 8 months.

The linux installation works without any problems on my Linux system (openSuSE 13.1). It's important to start the program from the wrapper shell script, Cosmographia.sh, rather than via the executable.

Fridger

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PostPosted: Sun, 18-10-15, 8:02 GMT 
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Hi guys! I would have loved to step in for something else, but apart a texture teaser every 6 months from Fridger, unfortunatly there is not much to be existed for over here from the point of view of a neophyte like me.

Now, as this morning I stumbled upon the october 14 encelade flyby sim from Nasa I could not avoid recalling this recent thread. You may have seen it already but in case not, you can find it here : https://www.youtube.com/watch?v=G-i_4hbi7hI

I guess new stunning images will come pretty soon!


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PostPosted: Tue, 20-10-15, 18:59 GMT 
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Hi Pluto-aficionados,

Using my "best Pluto texture" (viewtopic.php?f=2&t=784) I compared both the Cosmographia-NASA rendering of a mutual Pluto-Charon eclipsing event of April 29 1987at 01h:01m (https://www.researchgate.net/profile/Ma ... jtRfQGXg4A) and celestia.Sci. In both cases the Pluto-Charon orbits (ephemerides) are still associated with significant uncertainties.. In case of celestia.Sci I am currently setting up a .ssc file using proper Spice kernels. Moreover, the considerable light travel time needs to be accounted for by all means.

Here is a comparison of the results for Pluto

[To enlarge the images click on it and then hit the browser fullscreen key (F11), please]
Attachment:
29041987_pluto_charon_cosmo.jpg
29041987_pluto_charon_cosmo.jpg [ 181.4 KiB | Viewed 1225 times ]

Attachment:
29041987_pluto_charon_sci2.jpg
29041987_pluto_charon_sci2.jpg [ 249.56 KiB | Viewed 1225 times ]


E.g. even for Cosmographia-Spice-NASA the first contact of Pluto and Charon happens at 10h:57m of April 29 1987. Apparently quite a few hours late. No idea whether ChrisL did include the light travel time (~4 h ?).

Attachment:
29041987_pluto_charon_cosmo2.jpg
29041987_pluto_charon_cosmo2.jpg [ 157.94 KiB | Viewed 1221 times ]

For celestia.Sci, the discrepancy is even some hours larger (without the use of Spice kernels). Hence the orbits need further refinements in both cases...

So there is more to come soon...

The visible blue dot marks the Earth direction for proper alignment.

Enjoy,
Fridger

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PostPosted: Wed, 21-10-15, 19:57 GMT 
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Further tests: mutual Pluto-Charon eclipse events:
-------------------------------------------------------------------------------
In the paper that I have quoted in my previous post,

https://www.researchgate.net/profile/Ma ... jtRfQGXg4A

various such events were observed from Earth in 1986 / 1987 (cf Table III), i.e. almost 30 years ago! Such mutual eclipsing events in the Pluto system happen only during distinct "seasons" which lie quite far apart in time due to Pluto's large orbital period of ~ 248 years!

Let me display an example here as simulated within celestia.Sci and my current NON-Spice (best guess) solarsys.ssc: Eclipse: June 16, 1987, ending contact around 22h:40m UTC

It's a nice one where Charon's big shadow moves across Pluto. Altogether it lasts about 4h. Since this is a dynamical event, I made a little video from it (converted to MP4 format).
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Video of Pluto-Charon eclipse in June 16, 1987 (mp4)
Hit on fullscreen button in your video player (e.g. vlc)!
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++
You may read-off the actual parameter values in the usual places of the screen. Apparently, the eclipse shadow finishes pretty accurately around 22h:40m. Hence my orbits can't be all that inaccurate ;-)

A display of the correct eclipse times requires activation of the LightTravelDelay (LT) with Earth (!) being selected. If Pluto had been selected instead, the LT is ZERO, of course, since the observer is located very close to Pluto, not Earth. And the predicted UTC eclipse times refer to earthbound observations, not to Pluto-based ones ;-)

The yellow dot on Pluto again indicates proper alignment towards the Sun.

Enjoy,
Fridger

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