Voyager and Galileo Images of Ganymede, The Ganymede images and mosaics thread |
Voyager and Galileo Images of Ganymede, The Ganymede images and mosaics thread |
Oct 1 2010, 03:53 PM
Post
#46
|
|
Senior Member Group: Members Posts: 1452 Joined: 26-July 08 Member No.: 4270 |
That's very nice!
-------------------- -- Hungry4info (Sirius_Alpha)
|
|
|
Oct 1 2010, 04:41 PM
Post
#47
|
|
Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Superb work!
-------------------- |
|
|
Oct 1 2010, 06:11 PM
Post
#48
|
|
Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Beautiful!
-------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
|
|
|
Oct 1 2010, 06:44 PM
Post
#49
|
|
IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
One more example of what can be done with the Voyager images using modern computers and software. This is one of the best Voyager mosaics I have seen of Ganymede and of course much better than any of the official stuff produced back in 1979.
|
|
|
Oct 1 2010, 07:16 PM
Post
#50
|
|
Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
Thanks!
Yes, new reprocessed images from Voyagers are mostly better than old official versions, but I have great respect to people who made this old images. With much slower computers and not very user friendly software, it must have been really damn difficult. -------------------- |
|
|
Oct 1 2010, 08:11 PM
Post
#51
|
|
Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Many were processed using a VAX. I can't even imagine it.
-------------------- |
|
|
Oct 1 2010, 08:23 PM
Post
#52
|
|
Member Group: Members Posts: 655 Joined: 22-January 06 Member No.: 655 |
Very impressive Machi.
The terrain in the far south near the terminator is incredibly similar to Enceladus' south polar terrain (on a much larger scale of course) |
|
|
Oct 2 2010, 09:01 AM
Post
#53
|
|
Lord Of The Uranian Rings Group: Members Posts: 798 Joined: 18-July 05 From: Plymouth, UK Member No.: 437 |
Brilliant work, Daniel!
I'm beginning to think that a website based upon the NASA Planetary Photojournal site, but dedicated solely to 'amateur' image products, might be a good way of collating the ever-growing portfolio of great work produced by people on here. We could even call it the 'UMSF Photojournal'. Oh, Ted: I used to own a VAX. It was the best darn vacuum-cleaner I've ever had... -------------------- |
|
|
Oct 2 2010, 06:18 PM
Post
#54
|
|
Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
Ian, I have actually similar idea and in fact it's partially on the way. Because I haven't my own server, I must use public server with 300 - 500 MB data storage.
So I suppose, that in first phase I will create simple gallery with my images (png's) and then (second phase) I will be using only thumbnails with location reference to full image or page with image. There is minor problem with my programming skills, so I will plan only simple html gallery with thumbnails and basic informations about every image. -------------------- |
|
|
Oct 18 2010, 03:36 AM
Post
#55
|
||
Junior Member Group: Members Posts: 74 Joined: 9-October 10 From: Victoria, BC Member No.: 5483 |
This is a colour global view of Ganymede, taken using Orange, Blue and Violet images (in the RGB channels respectively) from Voyager 2. I made it using ISIS around 1998 or 1999, it's an orthographic reprojection of a mosaic of the antijovian hemisphere. I don't think I stretched the histograms in the component images at all.
I wish I could remember what specific images I used (I'm reasonably sure that I was using the images that start around C2063105). Annoyingly I can't find my notes on it - I'm lucky I actually managed to find the image itself! . I think there were around 39 images in total (about 13 for each filter)? I do remember that I had to manually match the images - I didn't have IDL or any of that other fancy stuff, working in a UK university that didn't have the funds to buy it. I looked at each adjacent/overlapping image pair in a given filter, looked for a minimum of three match points between the images, and noted down the pixel locations for all of them in a little black book and in a text file that ISIS would read, and then did that several times for each overlapping image pair - it took weeks to find all the match points, and sometimes ISIS would still just not match the darn thing properly and so I had to go back and find different ones. As it is it nearly broke the computer I used to make it (which of course was great for the time and completely laughable by modern standards), and I think the end mosaic (in original .cub format) was over a gigabyte in size! I'd have to leave the ISIS script to take it from level 0 to level 4 running overnight and hope it all worked. I also used updated SPICE data for Voyager that I got from Tim Colvin at RAND Corporation (that IIRC wasn't in ISIS at the time). The resolution of the mosaic is 2 km/pxl. Probably not awesomely useful for science, but I'm pretty proud of it considering the effort it took to make it - hope you like it . |
|
|
||
Oct 18 2010, 01:35 PM
Post
#56
|
|
Member Group: Members Posts: 207 Joined: 6-March 07 From: houston, texas Member No.: 1828 |
>>I wish I could remember what specific images I used (I'm reasonably sure that I was using the images that start around C2063105). Annoyingly I can't find my notes on it - I'm lucky I actually managed to find the image itself! . I think there were around 39 images in total (about 13 for each filter)?
yep those are the numbers. it was a 3-color 6-frame mosaic (18 total). i dont know why it didnt cover the poles. the basic color patterns of ganymede are in this mosaic: the reddish color of dark terrain, the different colors of the dark rays, even the bluish polar caps in a few spots. i used it in the Atlas to fill certain areas but used lower resolution Galileo color because that included IR data globally. -------------------- Dr. Paul Schenk, Lunar and Planetary Institute, Houston TX
http://stereomoons.blogspot.com; http://www.youtube.com/galsat400; http://www.lpi.usra.edu/science/schenk/ |
|
|
Oct 18 2010, 04:28 PM
Post
#57
|
|
Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
One of my Ganymede mosaics uses that set with wide angle data for the poles.
-------------------- |
|
|
Oct 18 2010, 06:17 PM
Post
#58
|
|
Junior Member Group: Members Posts: 74 Joined: 9-October 10 From: Victoria, BC Member No.: 5483 |
Only 18 images? Seemed like a lot more! (maybe I'm thinking of how many overlapping pairs there were, or something).
So barring the slight difference that using OBV filters instead of RGB ones would make, is this actually close to the colours that Ganymede would have if we were there looking at it with our own eyes? There doesn't seem to be much of a colour/brightness difference between "bright" and "dark" terrains (the ejecta around Osiris is much more noticeably brighter though). |
|
|
Oct 18 2010, 06:41 PM
Post
#59
|
||
Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
So barring the slight difference that using OBV filters instead of RGB ones would make, is this actually close to the colours that Ganymede would have if we were there looking at it with our own eyes? It's pretty close, I'd say. FWIW, I ran your image (great mosaic, btw!) through some code to interpolate the entire visible spectrum (linearly between OBV wavelengths) and convert to sRGB: The brightness is due to gamma-correction, the actual color is similar to yours, only less reddish/brownish. -------------------- |
|
|
||
Oct 18 2010, 07:23 PM
Post
#60
|
|
Junior Member Group: Members Posts: 74 Joined: 9-October 10 From: Victoria, BC Member No.: 5483 |
Very nice! Thanks for doing that, I've often wondered if there was any software that could interpolate between the filters.
|
|
|
Lo-Fi Version | Time is now: 23rd September 2024 - 04:25 PM |
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. |