Celestia Forums

Hi Developers,

I have a problem with the add-in for Mercury and Gemini spacecraft.

How to locate those objets in Celestia (1.2.0)?

First, I unzip the files into C:\program files..\Celestia Directory, and now???

Thanks !!

Rodrigo.

Great program, but the documentation stinks.

skippymcgraw wrote:Great program, but the documentation stinks.

But the quality/price ratio is very good. You can always write some? :-)

Greetings. Did you ever find out how to use the add-on of mercury & gemini?? I have the same problem. How to locate them??

Thanks. Larry... ldweber51@msn.com

The objects must be added to a .ssc file, located in /extras in your application folder. (My mac OS X procedure may be slightly different than yours.) There *should* have been a .ssc file included with the download. All the files in the .zip maybe shouldn't have been placed in the same directory.

I almost didn't post cause of skippymcass, but no reason to punish the rest of you for his rude comments.

AKcrab wrote:The objects must be added to a .ssc file, located in /extras in your application folder. (My mac OS X procedure may be slightly different than yours.) There *should* have been a .ssc file included with the download. All the files in the .zip maybe shouldn't have been placed in the same directory.

I almost didn't post cause of skippymcass, but no reason to punish the rest of you for his rude comments.

I would say the skippymcass was a little more rude than his comment...but no...I really dont care...

Email Chris and he'll send you one...when hes got the time...

I would say the skippymcass was a little more rude than his comment...but no...I really dont care...

Well, he's right: the documentation for Celestia pretty much sucks right now.

Anyhow, the files in shroxclassic.zip should unpack into the correct directories--3ds files into models, ssc files into extras.

--Chris

chris wrote:

I would say the skippymcass was a little more rude than his comment...but no...I really dont care...

Well, he's right: the documentation for Celestia pretty much sucks right now.

Anyhow, the files in shroxclassic.zip should unpack into the correct directories--3ds files into models, ssc files into extras.

--Chris

Well if I had the time I could do something for that...but you would be better off getting someone with better knowledge of astronomy...as I have very little

My first choice would be Bruckner...who I think mentioned he would do as such anyway...or it might have been hank...If you need help bud...ask

My Mars cloud map is looking better now:

http://world.std.com/~mmcirvin/mars-clouds.png

I'm wondering how I should properly distribute this (perhaps via Bruckner's site). To use it, as far as I know, requires hacking solarsys.ssc rather than making an add-on .ssc folder. You have to add a few lines to the Mars atmosphere:

Atmosphere {
[...]
CloudHeight 10
CloudSpeed 0
CloudMap "mars-clouds.png"
}

Thus I'm reluctant to just create a zip archive that installs into the Celestia directory, as it would have to write over the user's solarsys.ssc, which seems fraught with unintended side effects, especially as Celestia evolves.

Any tips on what I should do?[/url]

Matt McIrvin wrote:My Mars cloud map is looking better now:

http://world.std.com/~mmcirvin/mars-clouds.png

By the way, here's a snapshot of how it looks:

http://world.std.com/~mmcirvin/mars-with-clouds.jpg

It's pretty much fictional, but loosely inspired by the appearance of 1999 Hubble pictures, and some Viking and MGS shots.

My advice is: just send it to me as it is. Don't worry about zip files... You're right, I'd be reluctant to overwrite any user's solarsys.ssc, but not just because of future modifications, but of present hacking.

Many people (me included) have various solarsys.ssc lying around to test different things. Your add-on needs manual editing as it is, unless... (now comes the tiny feature request directed to Chris)

Chris: would it be very difficult if .ssc files contained in the extras directory could override commands given in solarsys.ssc? Imagine you want to experiment with modifications to current objects in the Solar System (as is the case now: an optional, fictitious, cloud texture for Mars). I could redefine Mars in a file called marsclouds.ssc (or any other name you like, the redefinition should be solved by object name) with the new cloud texture, without affecting the solarsys.ssc shipped by default (or otherwise tweaked by me!) To make things easy, the redefinition could be complete, i.e., no "cascading" or "union" (or inheriting, for that matter) for data not overwritten by the redefinition should be performed. That is: if the Moon is defined with certain texture and orbital parameters in solarsys.ssc, and I redefine "Moon" "Sol/Earth" as a body with a very eccentric orbit (without specifying texture), it should appear totally blank. The "Moon" section in solarsys.ssc would thus be ignored.

Well... I guess this is enough for today. It's late here...

Best regards to all.

Bruckner

bruckner wrote:Chris: would it be very difficult if .ssc files contained in the extras directory could override commands given in solarsys.ssc?...

To make things easy, the redefinition could be complete, i.e., no "cascading" or "union" (or inheriting, for that matter) for data not overwritten by the redefinition should be performed.

Sounds like the right way to approach it; otherwise we'd perhaps be paying too much attention to the fact that .ssc is .css spelled backwards! And we know how hard
that was to implement...

Don't mention it... at least Mozilla 0.9.9+ is asymptotically near full compliance

Bruckner

I absolutely Love this program! I do a whack of lectures for various schools, boys groups, girls groups and special interest groups. It is my hope that very soon we will have some much needed equipment to make the world of astronomy much more exciting than before. ie: Laptops and Proxima.

Offering children a 100 by 100 inch screen in which to view the heavens. This program should and will, bring some huge excitement to the classrooms!

My question to the author's or those in the know, is will you be able to create an add-on to include the 110 Messier Objects (the brightest objects celestial objects found by comet hunter Messier in the 1600's) ie: The Orion's Nebula, Crab Nebula, Globular Clusters and the like.

If I had an inkling as to how to go about this, I would do it! But if this is too much to ask for I fully understand. The work that has gone into this program to date is absolutely OUTSTANDING!

I absolutely love it.
Paul Greenhalgh
Fraser Valley Astronomers Soc.
http://www.fvas.net

bruckner wrote:Chris: would it be very difficult if .ssc files contained in the extras directory could override commands given in solarsys.ssc? Imagine you want to experiment with modifications to current objects in the Solar System (as is the case now: an optional, fictitious, cloud texture for Mars). I could redefine Mars in a file called marsclouds.ssc (or any other name you like, the redefinition should be solved by object name) with the new cloud texture, without affecting the solarsys.ssc shipped by default (or otherwise tweaked by me!) To make things easy, the redefinition could be complete, i.e., no "cascading" or "union" (or inheriting, for that matter) for data not overwritten by the redefinition should be performed. That is: if the Moon is defined with certain texture and orbital parameters in solarsys.ssc, and I redefine "Moon" "Sol/Earth" as a body with a very eccentric orbit (without specifying texture), it should appear totally blank. The "Moon" section in solarsys.ssc would thus be ignored.

I like this idea. The danger is that among the files in the extras directory, there could be multiple definitions of the same object and no way to determine which should be used. With a lot of files in extras, this could get very messy. Any suggestions on how to resolve this? Or is it better to ignore it?

--Chris

I believe you can already add all the Messier objects which are
galaxies by editing the galaxy definition file, provided that you
can obtain the necessary parameters (distance, size, orientation,
classification) for those objects. I'm not sure, but you might be
able to fake globular clusters as very small spherically shaped
elliptical galaxies. If not, I think globular clusters probably would
not be hard to add because their shapes are predictable.

The big problem is gaseous nebulae, because we don't really
know their three-dimensional shapes, and their illlumination
from nearby stars is complicated.

The difficulty is that Celestia is fundamentally three-dimensional, so
just painting a jpeg of an observatory photo on the celestial sphere
really won't cut it.

I'm not saying it's impossible to do something reasonable for these
objects, but I suspect that most of the work will be in creating models
for individual objects, rather than in the code.

- Hank

I should mention also that I've defined an XML format to replace .ssc files, and I have a working parser. The only reason that Celestia 1.2.4 doesn't use XML is that I haven't figured out how Celestia to work with all the different versions of libxml on various Linux installations.

--Chris

Well, I have an idea on how to create the nebulae. We could take the pictures, and use some educated guesswork based upon the pictures. Then, we would also have to guess the depth of the nebula, based upon the farthest star in it.

'Course, I couldn't help, because I don't have any modeling programs, and I am not very good at guesswork.

Anonymous wrote:The difficulty is that Celestia is fundamentally three-dimensional, so
just painting a jpeg of an observatory photo on the celestial sphere
really won't cut it.

The photo-billboard approach might still be an entertaining add-in. Keep in mind that in a sense this problem already exists for stars, since the distances in the Hipparcos database really aren't that accurate beyond a few hundred light-years (even neglecting the effect of star motion and light-speed lag, which means that the stars aren't really where we see them).

You can't expect the night sky from, say, Deneb to be accurately represented-- but it's not that far off if you just go to Arcturus or Aldebaran. Many of the picturesque nebulae are pretty far away, so they'll still look all right from a few dozen light years from Sol if they are just transparent billboards.

I agree that it would be nice to have more accurate models that you could fly around-- but a billboard approach could be a good starting point, with some of the "greatest hits" like the Orion and Crab nebulae represented more accurately as people make models for them. (Think of how the mountains evolved in successive versions of SubLogic/Microsoft Flight Simulator.)

Matt McIrvin wrote:The photo-billboard approach might still be an entertaining add-in...

Thinking about it some more, I suppose that even with the billboard approach, you'd want to remove the stars from the pictures. A painting might be better than an actual astronomical photo.