Titan and Iapetus maps that I hadn't seen before

[Matt McIrvin]

Steve Albers has 1k Titan and Iapetus textures that incorporate Cassini data!

The Iapetus one doesn't include the New Year's flyby yet, but it's got information from earlier Cassini photos (and you can actually faintly see the west end of the equatorial ridge). The Titan one includes relatively high-res information from the T0 and TA encounters.

My apologies if you've seen these already... I hadn't.

[Matt McIrvin]

...They have the longitude origin at the edge, so you'll have to perform the familiar offset-by-50% in order to make them match Celestia's convention, or modify solarsys.ssc appropriately. Also, the Iapetus one is actually 2k. I imagine that with the texture data we've got now, much higher-resolution textures will become worth making...

There's also one of Tethys on the site that has incorporated some Cassini pictures.

[John Van Vliet]

have you seen mine ti was painstakingly peased together from cassini
and i am working on an update that has better detail in the south

[Tetzauh]

have you seen mine ti was painstakingly peased together from cassini
and i am working on an update that has better detail in the south

Yes I have seen it at it's wonderful. Very good job! I can't wait to see your shot at Iapetus.

And speaking of Iapetus, I don't know much abou this, so pardon my asking, the new ridge discovered in the dark area, will it have to be represented from the 3d mesh? or can it be represented with the bumpmap option of celestia?

[lostfisherman]

JFYI Steve Albers site is updated up to late January, including recent Cassini images since then of Iapetus and Rhea.

[t00fri]

JFYI Steve Albers site is updated up to late January, including recent Cassini images since then of Iapetus and Rhea.

Yes, but something went wrong with his hires projection of Titan. The latest NASA coodinates of the Huygens landing site don't match with his map. That's why I have started from scratch. In my Titan texture, the landing site fits...

Some other textures (Iapetus,...) are interesting, however.

Bye Fridger

[Guest]

Greetings Fridger (and all),

Good point about Titan, Fridger. I had offset the images too far north to fit the older
basemap I had been using that you might recognize . I reworked the locations
a bit now. I recently noticed the Cassini map you had posted on the other thread - this
helped me to adjust the locations, thanks. The Huygens landing site should be closer than before, though perhaps it could still be adjusted by a few pixels here or there. It might be interesting to overlay that VIMS Huygens footprint image to really get it refined. I also saw you had the Huygens lat/lon mentioned on the other thread - I'll have to review that as well.

As you may know my maps for Titan and the other Saturnian satellites are all
works in progress as the exciting Cassini data continues to come in.


Take care,

Steve Albers

P.S. Updated maps are at http://laps.fsl.noaa.gov/albers/sos/sos.html

[t00fri]

Greetings Fridger (and all),

Good point about Titan, Fridger. I had offset the images too far north to fit the older
basemap I had been using that you might recognize . I reworked the locations
a bit now. I recently noticed the Cassini map you had posted on the other thread - this
helped me to adjust the locations, thanks. The Huygens landing site should be closer than before, though perhaps it could still be adjusted by a few pixels here or there. It might be interesting to overlay that VIMS Huygens footprint image to really get it refined. I also saw you had the Huygens lat/lon mentioned on the other thread - I'll have to review that as well.

As you may know my maps for Titan and the other Saturnian satellites are all
works in progress as the exciting Cassini data continues to come in.


Take care,

Steve Albers

P.S. Updated maps are at http://laps.fsl.noaa.gov/albers/sos/sos.html

Greetings Steve,

unfortunately, I spotted your post only now (for various reasons, I often skip anonymous (Guest) posts...).

Good to know that we agree on the fine adjustments of the Titan maps. Of course my first lowres map had considerable uncertainties as to its absolute position, notably since I had to cut it out from some rather 'fat' coordinate frame.

That's why I went the opposite way with my recent update texture: starting from the hires landing site as the coordinate reference, I adjusted the less accurate map overlays for best match.

I am very much looking forward to implementing further hires imaging from the Feb 15 Titan flyby! It looks like interesting, complementary views ahead of us, as may be anticipated from my 'preview' of the flyby with Celestia in the Users board.

Your other updated moonmaps look great! I might put my hands on implementing all recent hires imaging of Iapetus into one map over the weekend...

One issue though: Your Tethys map looks far too greenish-yellow to me, in view of the very slight yellow coloration visible on the latest hires imaging. I have done some recoloration in my private 2k version, a 'thumbnail' reduction of which looks like so:


The colors are computer-mapped directly from the hires-natural color photo of Tethys.

Also, I reduced some of the extreme shadow contrast from the glacing illumination of the hires image of Iapetus at the northern rim. This allows for a smoother fitting of the hires texture into the map.

I guess you know that in Celestia, the texture conventions request a 180 degree longitude offset relative to yours.

Finally, please dont' forget to add the second 'p' to the end of my family name on your site

Bye Fridger

[Guest]

Hi Fridger,

I appreciate seeing your discussion and feedback. I'll plan to fix the typo when I work on the website next week. Sorry my "guest" postings are like needles in the haystack, sometime I'll have to figure out how to become a member.

I've been using 180 deg longitude as the center mainly to match some of the maps I've seen from the USGS, Cassini, Galileo, and elsewhere. It's a tough call though and I realize it can be inconvenient for some to switch (as I also need to do) when displaying my maps via Celestia.

Interesting observations about Tethys. I'll have to figure out if there is some reason my remapping steps are causing the saturation of the "natural color" Cassini image to be increased. If I can justify making the Cassini image a more neutral color, then I can justify making the Voyager based background map correspondingly more neutral. Your adjusted map does look pretty good however. I also have been trending towards reducing the shadows along the terminator. As part of that process I saw the need to reduce a blue bias in the darkest portions of the Cassini image. I'll have to check if that adjustment somehow made the brighter portions more yellow. We'll all hopefully be converging on the true reality as time goes along.


Later,

Steve Albers

[Guest]

Hi Steve,

Hi Fridger,

I appreciate seeing your discussion and feedback. I'll plan to fix the typo when I work on the website next week. Sorry my "guest" postings are like needles in the haystack, sometime I'll have to figure out how to become a member.

Becoming a member is very easy: Just click 'Register' in the box on the top right. After acknowledging the following page, you will arrive at your personal 'Profile' form. Enter a user name of your choice, a password, and optionally whatever else you like people to know about you. Like Web site URL, email,... You may adjust the time display to your local time, enter an Avatar if you like (I did not even know what this is until a week ago ). Also you may select a graphical theme for the forum. I use 'silver' I guess. Your Profile can be re-edited any time later.

...
Interesting observations about Tethys. I'll have to figure out if there is some reason my remapping steps are causing the saturation of the "natural color" Cassini image to be increased.

Did you perhaps misunderstand me here? Certainly I did not change the hires 'natural color' Cassini image within the global map above. The idea was to rather use it as a 'color-template' for standard color-mapping macros in image manipulation programs like GIMP. That's how my above 'thumbnail' texture was colorized, after switching it into grayscale mode. I never fiddle with colors by hand.

I am also looking forward to your feedback during this fun process of texture mapping, while the Cassini mission continues to provide frequent, exciting imaging information...

Bye Fridger

[t00fri]

too bad I was logged out while I looked up the 'register' form

Bye Fridger

[scalbers]

Hi Fridger,

If I understand correctly, you changed the color only on the Voyager based portion, and left the Cassini portion mostly as I had it, or possibly less saturated that I did?

I can point out that I did change the Cassini image color, by correcting a blue bias in the shadowed terminator regions (even showing up on the night side). Perhaps that increased the saturation of the brighter yellow portions too much as a side effect. I'll have to see if this can be done differently, in order to show some sort of realistic hue variation over all of the Cassini Tethys image. If I can figure that out better, then I can make it match with a more neutral colorization in the Voyager-based areas.

Also if I recall, the original Voyager-based map I used had even more color in it, so we are both trending towards a more neutral color.

Later,

Steve

[t00fri]

Hi Fridger,

If I understand correctly, you changed the color only on the Voyager based portion, and left the Cassini portion mostly as I had it, or possibly less saturated that I did?

I can point out that I did change the Cassini image color, by correcting a blue bias in the shadowed terminator regions (even showing up on the night side). Perhaps that increased the saturation of the brighter yellow portions too much as a side effect. I'll have to see if this can be done differently, in order to show some sort of realistic hue variation over all of the Cassini Tethys image. If I can figure that out better, then I can make it match with a more neutral colorization in the Voyager-based areas.

Also if I recall, the original Voyager-based map I used had even more color in it, so we are both trending towards a more neutral color.

Later,

Steve

Steve,

Welcome Mr. ScAlbers !

Basically I agree, but I did not make use of ANY of your coloration whatsoever. I used the /original/ Cassini natural color image (that was also part of your global map) as a color template, while switching your whole texture to grayscale at the beginning. Then I changed back to RGB mode to allow for coloration.

So the color of the whole global map was uniformly mapped from that template. Of course the color of the hires Cassini part of the global map is correctly restored.

I checked the Voyager color explicitly. It was considerably more yellow than the Cassini color. Usually the colors were not too good at that time...

Bye Fridger

[danielj]

I like the new Thetys map,but is it ready to download?Or is just an experimental one?

Greetings Fridger (and all),

Good point about Titan, Fridger. I had offset the images too far north to fit the older
basemap I had been using that you might recognize . I reworked the locations
a bit now. I recently noticed the Cassini map you had posted on the other thread - this
helped me to adjust the locations, thanks. The Huygens landing site should be closer than before, though perhaps it could still be adjusted by a few pixels here or there. It might be interesting to overlay that VIMS Huygens footprint image to really get it refined. I also saw you had the Huygens lat/lon mentioned on the other thread - I'll have to review that as well.

As you may know my maps for Titan and the other Saturnian satellites are all
works in progress as the exciting Cassini data continues to come in.


Take care,

Steve Albers

P.S. Updated maps are at http://laps.fsl.noaa.gov/albers/sos/sos.html

Greetings Steve,

unfortunately, I spotted your post only now (for various reasons, I often skip anonymous (Guest) posts...).

Good to know that we agree on the fine adjustments of the Titan maps. Of course my first lowres map had considerable uncertainties as to its absolute position, notably since I had to cut it out from some rather 'fat' coordinate frame.

That's why I went the opposite way with my recent update texture: starting from the hires landing site as the coordinate reference, I adjusted the less accurate map overlays for best match.

I am very much looking forward to implementing further hires imaging from the Feb 15 Titan flyby! It looks like interesting, complementary views ahead of us, as may be anticipated from my 'preview' of the flyby with Celestia in the Users board.

Your other updated moonmaps look great! I might put my hands on implementing all recent hires imaging of Iapetus into one map over the weekend...

One issue though: Your Tethys map looks far too greenish-yellow to me, in view of the very slight yellow coloration visible on the latest hires imaging. I have done some recoloration in my private 2k version, a 'thumbnail' reduction of which looks like so:


The colors are computer-mapped directly from the hires-natural color photo of Tethys.

Also, I reduced some of the extreme shadow contrast from the glacing illumination of the hires image of Iapetus at the northern rim. This allows for a smoother fitting of the hires texture into the map.

I guess you know that in Celestia, the texture conventions request a 180 degree longitude offset relative to yours.

Finally, please dont' forget to add the second 'p' to the end of my family name on your site

Bye Fridger

[t00fri]

Not yet. It's still in my private 'treasure box' . But Steve Albers is also working on this now...

Bye Fridger

[Adreitz]

Hey, guys. I've done some of my own modifications to Steve's texture maps. I tried to upload them to Celestia Motherlode, but apparently that didn't go through because they're still not up in a creators' folder. So instead, I uploaded them to my Spymac page. Try downloading them and let me know what you think. Sorry if the page is slow or goes over bandwidth occasionally.

http://adreitz.spymac.net/

Aaron

[scalbers]

Hi,

Just as a reminder, you can click on the 'www' icon to go to my planetary maps page. You can see there updates from this week for Tethys and other satellites. I plan to continue to update all the Saturnian satellites periodically in the future.
Enjoy...