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Posted by: Tman Dec 14 2005, 10:29 AM

On November 29, 2005, Cassini shot a nice sequence from an "encounter" of Janus and Epimetheus. In this sequence also appear few stars - two brighter and three quite faint. But first I was only stumbled across one of the brighter in this GIF animation: http://www.greuti.ch/cassini/fb_epimetheus_n00043503-36.gif (large file (1,4 MB))

Tilmann was able to identify this spot as UCAC2-30620769 (or http://simbad.u-strasbg.fr/sim-id.pl?Ident=HD%20217167&Epoch1=2000%2E0&Epoch2=1950%2E0&Epoch3=2000%2E0&output%2Emes=o%2Ecatall%2C&NbIdent=1&output%2Emax=all&Equi1=2000%2E0&Equi2=1950%2E0&FrameList=FK5&Equi3=2000%2E0&Radius=10&EpochList=2000%2E0&CooFrame=FK5&Bibyear1=1983&EquiList=2000%2E0&CooEpoch=2000&Bibyear2=2006&protocol=html&output%2Emesdisp=N&CooEqui=2000&Radius%2Eunit=arcmin&Frame1=FK5&Frame2=FK4&%2Dsource=simbad&Frame3=G)
So it was easy to find a picture of the starfield where the two moons of Saturn were in front of at this time - and to make a nice (fictive) animation with the cutted moons: (500 KB) http://www.greuti.ch/cassini/epimetheus_janus_starfield.gif

To show how exact the orientation could be, additionally two images that show the position of the visible stars in the Cassini pictures at the beginning and at the end of the GIF animation (each time the entire picture/frame of Cassini overlay (30% transparent) the picture of the starfield):
http://www.greuti.ch/cassini/epimetheus_janus_starfield_marked2.jpg
http://www.greuti.ch/cassini/epimetheus_janus_starfield_marked.jpg

Nico (SigurRosFan) still made a nice picture of it with some labeled features of the starfield:

http://xs59.xs.to/pics/05502/Cassini_and_Arp_314.jpg

Posted by: elakdawalla Dec 14 2005, 03:05 PM

WOW, that is really cool work!

Posted by: elakdawalla Dec 14 2005, 06:57 PM

I'm getting broken links when I try to view these now. I was on my way to a meeting with someone and was going to show these pictures if anybody is reading who can do something about this, or who can repost them, before 1:00 Pacific time, I may still be able to show this work off!

--Emily

Posted by: Tman Dec 14 2005, 08:23 PM

Sadly, my webhost is completely down at the moment

I will try to attach the 500 KB GIF!

And btw. thanks for the compliment

Posted by: elakdawalla Dec 14 2005, 08:27 PM

THank you -- Just in time! I'll be able to show this now. How about the JPGs showing how you lined up the individual frames?

--Emily

Posted by: Tman Dec 14 2005, 08:30 PM

gladly

Posted by: Tman Dec 14 2005, 09:56 PM

(I have to add) One thing is probably missing in the "moons in front of the starfield" GIF. In the original Cassini pictures/frames one can see Saturn's ring, rather faint, but it is there I think.

It's not possible to show it in the GIF because it's too faint for cutting, but you may it imagine therein

Posted by: elakdawalla Dec 15 2005, 02:49 AM

I showed this to a couple of Official People in JPL's Multi-mission Image Processing Laboratory today and it knocked their socks off One message that came out of that meeting: they are excited to see people like you guys messing with this data. Keep up the gorgeous work!

Maybe that ring will be more visible once the images are released to the PDS, and then someone can clip it out as a transparent object and superimpose it...

--Emily

Posted by: SigurRosFan Dec 15 2005, 11:37 AM

Thanks for your nice feedback.

Posted by: SigurRosFan Dec 15 2005, 05:06 PM

A new (bigger) version. Enjoy it!

Small galaxies, big moons:
http://xs59.xs.to/pics/05504/Cassini_Arp_314_big.jpg

Posted by: Tman Dec 22 2005, 11:01 AM

Inspired by Nico's improvements I tried a new version of the GIF including "more" moons and "more galactic" background: (640 kB) http://www.greuti.ch/cassini/epimetheus_janus_starfield2.gif
The moons got 1,2 times of the size in the original pics.

Additional a map that shows Saturn and the constellation borders in relation to this animation (yellow rectangle): http://www.greuti.ch/cassini/epimetheus_janus_starfield_marked3.jpg
Saturn is pretty exact at the position when the shoot sequence was started (01:08:00 UTC).

Posted by: Tman Dec 27 2005, 12:57 PM

Is there a possibility to show Janus and Epimetheus from above in a graphic, in relation to Saturn, its ring and Cassini, as they were orbiting Saturn at the time of this shoot sequence (Nov 29. 05)? Maybe at the time of the first pic/frame.

That would make the lot considerably clearer

Posted by: antoniseb Dec 27 2005, 01:34 PM

This is a very nice image. I've posted a link to it in my low-readership journal. If you'd like me to break the link to minimize traffic to your site let me know, and I'll do it ASAP.

BTW, I did a quick look for any color, higher resolution images of Arp 314 and came up empty. Does any one know of a good image of this pair?

Happy Johannes Kepler's 434rd Birthday.