Rev 165 Apr 23-May 11 2012, Enceladus E19 and close Dione flyby |
Rev 165 Apr 23-May 11 2012, Enceladus E19 and close Dione flyby |
Apr 22 2012, 08:25 PM
Post
#1
|
|
Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
The latest looking ahead article is available.
This revolution includes another 74km Enceladus flyby with infrared studies on approach and recession, and RSS as prime instrument at C/A for gravity readings over the south pole. We don't get this close to Enceladus again now until October 2015. Also a close Dione flyby at around 8000km with some great hi-res imaging and mosaics to look forward to, and some distant Titan cloud hunting. |
|
|
May 2 2012, 05:29 PM
Post
#2
|
|
Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
Initial far-encounter images have landed - Enceladus from distance, and some nice plume shots.
Can anyone explain this image? The top half is fairly 'clean' but the bottom half is speckled with cosmic-ray hits and sundry noise - I've not seen this before, how does it occur in the same image?? Looking forward to what should be some splendid close Dione pics.... |
|
|
May 2 2012, 06:54 PM
Post
#3
|
|
Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
Can anyone explain this image? The top half is fairly 'clean' but the bottom half is speckled with cosmic-ray hits and sundry noise - I've not seen this before, how does it occur in the same image?? I forget the exact technical reason, but in essence the CCD readout speed overwhelmed the speed the downstream components can handle (say if the spacecraft recorder configured telemetry rate was set lower) so the lower part of the image was forced to sit on the CCD for a while longer. This increases dark current background (brightening seen visible) as well as chances of cosmic ray hits. BTW, this complicates dark current calculations for calibration quite a lot. Chances of this happening depend on whether both cameras are active simultaneously, binning and compression mode, spacecraft telemetry pickup rates (the speed at which ISS sends packets to the spacecraft recorders, which also depends on whether other instruments are actively collecting as well). -------------------- |
|
|
May 2 2012, 07:37 PM
Post
#4
|
|
Member Group: Members Posts: 754 Joined: 9-February 07 Member No.: 1700 |
ugordan, you understand that from an armchair? In Croatia? Why haven't they hired you yet?
|
|
|
May 2 2012, 07:41 PM
Post
#5
|
|
Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
It's explained in the extensive Porco, et. al. paper from 2004 about Cassini's ISS. Since I had to reverse-engineer most of the official calibration code for my purposes, I kind of needed to know things like this about the cameras...
-------------------- |
|
|
May 2 2012, 07:50 PM
Post
#6
|
|
Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
Wow! comprehensive answer ugordan, makes a lot of sense - thanks!
Jase |
|
|
May 2 2012, 10:32 PM
Post
#7
|
|
Senior Member Group: Members Posts: 1582 Joined: 14-October 05 From: Vermont Member No.: 530 |
Sounds like an interesting tradeoff between adding the additional complication of a dedicated buffer, or not. Since the buffer would be just another thing that could break.
|
|
|
May 3 2012, 07:48 AM
Post
#8
|
|
Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
There is a buffer, it's just not large enough to hold an entire unbinned frame. More on this in section 3.9.4. of the ISS paper I mentioned.
Now back to your regular science program schedule... -------------------- |
|
|
May 4 2012, 03:54 AM
Post
#9
|
|
Solar System Cartographer Group: Members Posts: 10145 Joined: 5-April 05 From: Canada Member No.: 227 |
http://saturn.jpl.nasa.gov/photos/raw/?start=1
Beautiful new pictures of Enceladus and Dione. I love the set with the big impact basin right at the top of the disk of Dione and Saturn behind it. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
|
|
May 5 2012, 12:08 AM
Post
#10
|
|
Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
I put together just a few of the goodies from this flyby: http://www.planetary.org/blogs/emily-lakda...2/05041544.html
But I can't believe I'm the first one to post any of these, with the first images having been on the ground for more than 24 hours now. Hellooooo! This is a forum about image processing! There are so many more awesome pictures from this flyby to play with! Is anybody else out there interested in playing and sharing? -------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
|
|
|
May 12 2012, 12:05 PM
Post
#11
|
|
Lord Of The Uranian Rings Group: Members Posts: 798 Joined: 18-July 05 From: Plymouth, UK Member No.: 437 |
-------------------- |
|
|
May 12 2012, 06:04 PM
Post
#12
|
|
Solar System Cartographer Group: Members Posts: 10145 Joined: 5-April 05 From: Canada Member No.: 227 |
Thanks! Very nice.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
|
|
May 24 2012, 10:53 PM
Post
#13
|
||
Lord Of The Uranian Rings Group: Members Posts: 798 Joined: 18-July 05 From: Plymouth, UK Member No.: 437 |
This is an enhanced IR-GREEN-UV view of a crater at 132 degrees W, 53 degrees N, which lies between the two principle arms of Arpi Fossae:
-------------------- |
|
|
||
May 24 2012, 11:25 PM
Post
#14
|
|
Member Group: Members Posts: 754 Joined: 9-February 07 Member No.: 1700 |
Ian, I feel like I'm looking at a seashell - wow! thanks
|
|
|
May 27 2012, 06:18 AM
Post
#15
|
|
Lord Of The Uranian Rings Group: Members Posts: 798 Joined: 18-July 05 From: Plymouth, UK Member No.: 437 |
You're welcome! I've added two more frames, turning it into a mosaic:
http://www.flickr.com/photos/10795027@N08/...57624830467026/ -------------------- |
|
|
Lo-Fi Version | Time is now: 18th April 2024 - 10:58 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |