Juno development, launch, and cruise, Including Earth flyby imaging Oct 9 2013 |
Juno development, launch, and cruise, Including Earth flyby imaging Oct 9 2013 |
Jan 18 2009, 11:47 PM
Post
#166
|
|
Senior Member Group: Moderator Posts: 3233 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
Well, if the camera sticks around till May 4, 2017, based on the trajectory in JPL Horizons, there is a nice encounter with Ganymede at 06:00 UTC on that day at a distance of 270,000 km when that satellite transits across Jupiter from Juno's perspective.
-------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
|
|
Jan 19 2009, 07:41 PM
Post
#167
|
|
Junior Member Group: Members Posts: 57 Joined: 21-September 06 Member No.: 1172 |
for those close-approach tables, you really need spice kernel files, but I believe that JPL Horizons also has this capability Currently I am using custom "brute force"method. It has moderate accuracy but still suitable for event search. I can summarize my results as following "Top Lists", 5-10 closest approaches for every Galilean. CODE Name______Date___________CA_Dist (km) Io 2017-Sep-24 17:18 141289 Io 2017-Jul-31 20:44 180270 Io 2017-Jun-07 00:10 217693 Io 2017-Apr-13 03:49 245136 Io 2017-Feb-17 07:16 279940 Io 2017-Apr-23 22:49 312179 Io 2016-Dec-24 10:44 312879 Io 2017-Jun-17 19:13 313812 Io 2017-Oct-05 11:57 321276 Io 2017-Aug-11 15:38 324122 Io 2017-Feb-28 02:33 330138 Io 2017-Aug-22 23:29 339674 Io 2017-Jan-04 06:14 341542 Europa 2017-Jul-31 14:58 110869 Europa 2017-Jul-20 18:37 224189 Europa 2017-Apr-01 21:46 230908 Europa 2017-Mar-22 01:44 266977 Europa 2016-Dec-02 04:38 348658 Europa 2016-Nov-21 08:40 355904 Europa 2017-Aug-11 09:54 382235 Europa 2016-Oct-31 02:45 453186 Europa 2017-Jul-09 21:34 453752 Europa 2017-Apr-12 16:05 455906 Ganymede 2017-Sep-24 06:52 149391 Ganymede 2017-Apr-12 16:14 168270 Ganymede 2017-May-04 09:14 216067 Ganymede 2016-Nov-20 19:02 372453 Ganymede 2016-Oct-30 02:09 400230 Ganymede 2017-Sep-02 11:54 410075 Callisto 2016-Dec-22 20:11 155386 Callisto 2016-Nov-19 14:44 232124 Callisto 2017-Jan-25 00:25 285824 Some interesting events are highlighted. Most promising encounter is one with Callisto (2016-Dec-22), close enough and just within first eight Juno's orbits. Assuming 3 degree FOV and 1024x1024 CCD, we may expect a spectacular view of that moon. Something like this: |
|
|
Jan 19 2009, 11:59 PM
Post
#168
|
|
Senior Member Group: Moderator Posts: 3233 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
Here is a nice overview from Celestia of Juno's orbital tour plus a nice shot from the first perijove shortly after (?) JOI:
-------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
|
|
Jan 20 2009, 12:15 AM
Post
#169
|
|
Senior Member Group: Members Posts: 2511 Joined: 13-September 05 Member No.: 497 |
Assuming 3 degree FOV and 1024x1024 CCD, we may expect a spectacular view of that moon. Sorry, but since Junocam has a 70-degree FOV none of these approaches is going to be spectacular. (All this was discussed upthread.) If there happened to be one closer than, say, 50,000 km, it might be worth doing, but even that's 40 km/pixel, only a 2-3x better than HST can get. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Jan 20 2009, 07:38 AM
Post
#170
|
|
Junior Member Group: Members Posts: 57 Joined: 21-September 06 Member No.: 1172 |
QUOTE ...but since Junocam has a 70-degree FOV... Could you provide me with detailed specification for Junocam? In this thread I found only bits of information. Anyways, we still have JIRAM imager. According to this presentation it has Pixel IFOV = 250 microrad, which is equivalent to spatial resolution of about 1 km/pixel for perijove passage (5000 km) - much more than Junocam has. So we still have a chance to obtain interesting images of the large moons. |
|
|
Jan 20 2009, 03:34 PM
Post
#171
|
|
Senior Member Group: Members Posts: 2511 Joined: 13-September 05 Member No.: 497 |
Could you provide me with detailed specification for Junocam? See http://www.unmannedspaceflight.com/index.p...st&p=131840 -- 4 km at 5000 km implies an IFOV of 800 urad/pxl. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Jan 20 2009, 06:25 PM
Post
#172
|
|
Junior Member Group: Members Posts: 57 Joined: 21-September 06 Member No.: 1172 |
4 km at 5000 km implies an IFOV of 800 urad/pxl. Thanks. I made another table of the best imaging opportunities: object name, date of the encounter, distance and maximum moon's image size in JIRAM and Junocam pixels. Here it is. CODE Name Date CA_Dist(km) JIRAM Junocam Ganymede 2017-Sep-24 06:52 149391 140,9 44 Ganymede 2017-Apr-12 16:14 168270 125,1 39,1 Callisto 2016-Dec-22 20:11 155386 123,6 38,6 Europa 2017-Jul-31 14:58 110869 113,2 35,4 Io 2017-Sep-24 17:18 141289 102,8 32,1 Ganymede 2017-May-04 09:14 216067 97,4 30,4 Callisto 2016-Nov-19 14:44 232124 82,7 25,8 Io 2017-Jul-31 20:44 180270 80,5 25,2 Callisto 2017-Jan-25 00:25 285824 67,2 21 Io 2017-Jun-07 00:10 217693 66,7 20,8 Io 2017-Apr-13 03:49 245136 59,2 18,5 Ganymede 2016-Nov-20 19:02 372453 56,5 17,7 Europa 2017-Jul-20 18:37 224189 56,0 17,5 Europa 2017-Apr-01 21:46 230908 54,4 17 Ganymede 2016-Oct-30 02:09 400230 52,6 16,4 Io 2017-Feb-17 07:16 279940 51,9 16,2 Ganymede 2017-Sep-02 11:54 410075 51,3 16 Europa 2017-Mar-22 01:44 266977 47,0 14,7 I wonder if resolution of JIRAM's images will be better or worse than that of MVIC images during NH Jupiter flyby 2 years ago? |
|
|
Jan 20 2009, 07:05 PM
Post
#173
|
|
Senior Member Group: Moderator Posts: 3233 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
I thought JIRAM had a smaller IFOV than JunoCAM, 250 microradians versus ~800? Therefore, wouldn't the spatial resolution of JIRAM be better than JunoCAM's?
-------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
|
|
Jan 20 2009, 07:36 PM
Post
#174
|
|
Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Those are not km/pixel numbers, they are the moons' maximum size in pixels
-------------------- |
|
|
Jan 20 2009, 08:43 PM
Post
#175
|
|
Member Group: Members Posts: 340 Joined: 11-April 08 From: Sydney, Australia Member No.: 4093 |
for those close-approach tables, you really need spice kernel files, but I believe that JPL Horizons also has this capability, but I haven't given a try. Well the Horizons webpage states the following, so get your resuts emailed to you for close approaches: QUOTE NOTE: Although the web-interface to HORIZONS provides nearly all capabilities of the primary telnet interface (and email interface), it does not provide the following: Small-body PARAMETER-MATCHING population searches (use the small-body search engine as an alternative) Integration of USER-INPUT ORBITS SPK BINARY FILE production CLOSE-APPROACH TABLES -------------------- |
|
|
Jan 20 2009, 09:01 PM
Post
#176
|
|
Senior Member Group: Moderator Posts: 3233 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
Those are not km/pixel numbers, they are the moons' maximum size in pixels Thanks for the correction there, thanks. I see it now. -------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
|
|
Jan 20 2009, 10:37 PM
Post
#177
|
|
Member Group: Members Posts: 340 Joined: 11-April 08 From: Sydney, Australia Member No.: 4093 |
A generic question about trajectories: does anybody in here know how to work the NAIF Spice Kernel tools/files (or whatever it's called ...) I think they would provide more accurate information for my realtime simulations than Horizons, but I just cant understand on how to work them. All I'd need is something to convert the SPK files into the good old 4 dimensions (x,z,y [wrt to solar system barycenter] and time). Feel free to send me a private message as well.
Thanks for your help in advance! -------------------- |
|
|
Jan 21 2009, 03:17 AM
Post
#178
|
|
Senior Member Group: Members Posts: 2511 Joined: 13-September 05 Member No.: 497 |
does anybody in here know how to work the NAIF Spice Kernel tools/files (or whatever it's called ...) I think they would provide more accurate information for my realtime simulations than Horizons... http://naif.jpl.nasa.gov/naif/toolkit.html but you will have to write code to use it. There's no reason that Horizons isn't just as accurate as it's probably just using the SPICE kernels internally anyway. And the orbit is going to be different than any available kernel anyway, based on the launch date and injection errors, TCMs, etc. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Jan 21 2009, 04:15 AM
Post
#179
|
|
Member Group: Members Posts: 340 Joined: 11-April 08 From: Sydney, Australia Member No.: 4093 |
Thanks for your reply! I have the toolkit ...
but you will have to write code to use it. ... which is the problem. I wasnt actually looking at it for Juno, but for some other missions and events (especially C/A) where Horizons is not up-to-date or as accurate as I'd like it to be. So if anybody has some ready-made SPK to (x,y,z,t) converter (the kind of one-click-and-it's-done) then I'd love a copy of it :-)EDIT 26-Jan Thanks to a very kind soul who provided a very easy solution (easy = I can handle it!) I can now load SPICE kernels into the realtime simulations, greatly enhancing the accuracy of the trajectory of some missions. First update applied to Dawn. Go Celestia! -------------------- |
|
|
Feb 4 2009, 10:19 PM
Post
#180
|
|
Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Something else came to mind with regard to Io...would JunoCam be able to do anything equivalent to a CPROTO oversampling to slightly improve resolution?
-------------------- |
|
|
Lo-Fi Version | Time is now: 4th May 2024 - 10:55 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. |