Problem : galaxies addons

[Cham]

Hello folks.

I'm new to Celestia. This is a marvelous program, and I'm very excited to his extension possibilities. I'm working on a Mac with OS X Panther. Recently, I added two small addons from this place :

http://www.lns.cornell.edu/~seb/celesti ... intro.html

and they worked correctly. But then, I wanted to add more galaxies (the local cluster is boring). I downloaded the galaxies_and_clusters file from this place :

http://63.224.48.65/~rassilon/

I installed it and it don't work ! There's nothing new in the DeepSpace. I installed it as a galaxies.dat file, like what is told in the file (by the way, there wasn't any galaxies.dat file in the Celestia/Data folder, is this normal ?). I also tried editing the deepsky.dsc file in the Data folder, but nothing new happened. What's wrong ?

How can I add galaxies ?

[Harry]

I installed it and it don't work ! There's nothing new in the DeepSpace.

Just to be sure: Did you enable galaxy rendering? Try pressing "u" if unsure.

Harald

[Cham]

I installed it and it don't work ! There's nothing new in the DeepSpace.

Just to be sure: Did you enable galaxy rendering? Try pressing "u" if unsure.

Harald

Of course it's On ! Actually, all options are On on my system (Mac dual 867 MHz, 1 GB ram, GeForce MX card, OS X Panther). I can see the galaxies of the local cluster (Milky Way, M31, M32 and the satellites, etc). But not more. The DeepSpace is all black. I want more galaxies. How ?

[granthutchison]

It's an old file: galaxies.dat is no longer used by Celestia - its function has been taken over by deepsky.dsc.
Comparing the syntax of the default deepsky.dsc with the galaxies add-on you've downloaded, I note that the keyword "Galaxy" is missing from each entry in your downloaded file:

Code: Select all

"Milky Way"

should read

Code: Select all

Galaxy "Milky Way"

and so on.

So I backed up my original deepsky.dsc, opened the downloaded add-on file in Word, and did a search-and-replace to replace every instance of
[paragraph mark]+[double quote]
with
[paragraph mark]+"Galaxy "+[double quote]
Then I saved the resulting file as deepsky.dsc.
Presto! All the galaxies appeared.
Presumably there's some analoguous process you can go through on your Mac to get the same effect.

Grant

[selden]

As an alternative to editing the file yourself, you might want to consider downloading the updated versions, which even include InfoURLs! (They weren't supported in the original galaxy.dat)

See http://www.lns.cornell.edu/~seb/celestia/catalogs.html

Just a few pages away from where you started...

[Cham]

As an alternative to editing the file yourself, you might want to consider downloading the updated versions, which even include InfoURLs! (They weren't supported in the original galaxy.dat)

See http://www.lns.cornell.edu/~seb/celestia/catalogs.html

Just a few pages away from where you started...

Thanks a lot for the help. I installed a galaxies file and it works

But is there only globulars and elleptical galaxies in there ? Where are the spirals ?

[selden]

Cham,

Celestia currently is very limited in what it can draw for remote systems of stars. It can draw only a few different shapes of fuzzy grey blobs. Maybe someday it will be able to draw more shapes.

When the Galaxy Type starts with an "S", that indicates that a spiral should be drawn. "galaxies_extended.dsc" specifies many different types of both elliptical and spiral galaxies, but Celestia draws exactly the same fuzzy S shape for all of the different types of spirals. Their arms are much dimmer than their centers, so you may need to adjust your display's brightness to see the arms.

I hope this clarifies things a little.

[Cham]

Thanks for the reply.

I experimented a lot with celestia and its galaxies. But except the one in the local cluster, I didn't found any s shaped galaxy. No spiral.

Do you have a spiral name to suggest, which should be in the database ? I want to see some remote spirals in the database. Please indicate some.

By the way, is it possible to have some imaginary planet and star systems in the Andromeda galaxy ? This should be cool ! I guess, to find it, it should be named before a real star, which we don't know in Andromeda, as it is too remote from us to see its stars ?

[selden]

Cham,

The catalog files used by Celestia, SSC (Solar System Catalog), STC (STar Catalog) and DSC (Deep Space Catalog) all are plain ASCII text. If you're running Windows, you can use Wordpad to look at them, for example.

An example of a spiral galaxy that's included in "galaxies_extended.dsc" is
NGC 1560
Remember to type a "space" between "NGC" and "1560"

Here's how it looks on my system.

(this links to a much larger picture)

As you can see, it's quite faint.

The galaxies that Celestia draws really aren't very exciting. That's why some people use the DSC Nebula declaration and create their own models.

Unfortunately, Celestia can not (yet?) draw stars and planets more than about 16,000 LY from the Earth. Please read the "preliminary user's FAQ", which is at the top of the User's Forum. Q/A #12 at http://63.224.48.65/forum/viewtopic.php?p=16526&highlight=#16526

[Cham]

Cham,
An example of a spiral galaxy that's included in "galaxies_extended.dsc" is
NGC 1560
Remember to type a "space" between "NGC" and "1560"

The galaxies that Celestia draws really aren't very exciting. That's why some people use the DSC Nebula declaration and create their own models.

Unfortunately, Celestia can not (yet?) draw stars and planets more than about 16,000 LY from the Earth. Please read the "preliminary user's FAQ", which is at the top of the User's Forum. Q/A #12 at http://63.224.48.65/forum/viewtopic.php?p=16526&highlight=#16526

This is sad. But I understand. It may be related to memory management.

Is there an addon which could change the galaxies shape, without pasting a flat picture on them ? The galaxies aren't so bad anyway.

Do you have other S shaped galaxies to suggest ? I like to learn where they are.

Thanks for your help.

[selden]

Cham,

There are a couple of examples of crude 3D models on my billboard page.

You should read the file "galaxies_extended.dsc". You can find the spirals in it as easily as I can. Open it in Wordpad if you're using Windows. One way to do that is to go to the "Start" menu and select the "Run" option. Type "wordpad" in its field "Open..." and click on OK. When Wordpad starts, you can use its "File" menu "Open" option to browse to the directory where you put the DSC file. If you're uisng XP, you can click on the file with the RightMouseButton and select Open or OpenWith. Then select WordPad from the list of programs.


I hope this helps.

[Guest]

Thanks. I'll try the model.

I'm using a Mac, and it's really easy to open the file.

It's so exciting ! With Celestia, I really feel like a small boy with a new toy !! It's like chrismas to me.

[Cham]

I tried the galaxy model. It works, but it's a bit too crude.

I like to be able to navigate inside the galaxy and visit some stars and planetary systems. It's too bad Celestia is limited in this respect, but I'll cherish this program for a very very long time anyway.

What I'm asking for now is the ability to see and visit more spiral type galaxies. I have the impression that the extended database is lacking many S-type galaxies, like NGC 4622, which wasn't in the database. Why ?

The Virgo cluster, is it in the database ?

[selden]

I have to admit that I really don't know what all the criteria were for including some galaxies and not others. All I did was convert Paul's catalog from the old .dat format into the new .dsc format and add the InfoURLs.

The original "galaxies.dat" primarily consists of somewhat less than a third of Tully's Nearby Galaxies Catalogue. That's the NBG catalog, not to be confused with the NGC catalog. NGC 4622 is not included in Tully's catalog. (I downloaded it just now and looked.)

According to the comments in the DSC file, it includes at least the Virgo, Ursa Major I/II, Coma Berenices, and Fornax clusters of galaxies. Tully's catalog lists quite a few others which might or might not be in the DSC file.

I hope this clarifies things a little.

[Cham]

Is there anything else, addons, we can add to Celestia in the DeepSpace ?

I tried the H-map. It didn't worked. I don't bother with it. I installed the crude 3D NGC 4622. Except "pasting" any 2D pictures, what else can we do in the deep space ? Are there any other 3D objects to download, to place with the galaxies ? Do you have any suggestions ? I understand there is really not much things in deep space, only galaxies and clusters, but maybe someone made something interesting.

Is there any 3D nebula, 3D gaz cloud model, etc ?

There appears to be so much things on the web, about Celestia, I'm becoming a bit confused. I installed many nice planetar systems, some 2D pictures of nebulas, Pioneer 10 and 11 models, and many other stuff.

Do you have any nice eye-candy suggestions ?

[RND]

The green blobby galaxies look kinda plain to me, cant some texture of actual galaxies be applied to them?

[selden]

In principle, of course. It's only programming.

In fact, I doubt that will happen, since the ability to create Nebula objects already exists and it lets you provide any model and surface texture image you want.

At this point, it might be appropriate for someone (or a group of people) to design a collection of 3D models to represent the different classes of galaxies.


p.s. if they look green on your system, then your display is seriously out of adjustment. They should be pure grey.