Celestia Forums

Hello!
Could sbd. pleae post here data for .ssc file of black hole in the center of our Galaxy?
Is sbd. making Smart1 odd-on? Or is it allready done?

cheers, Alex

I havent tried SMART1 in particular, but I have tried to plot a few low-thrust trajectories in Celestia, and for some reason, the trajectory traces come out looking all wrong, almost as if not every point specified is being plotted. However, when viewing the path of the spacecraft, it seems to be relatively accurate.

I've tried modifying a DSC file so that it would simulate the black hole texture as a nebula, lying oriented properly in the center of the galaxy. The only problem is, it's invisible. I can't seem to get ANYthing to appear at the center of the Milky Way. I'll keep trying though. (It should have worked theoretically, I just modified what Bode's Galaxy did and put new 3ds/jpg and at our galaxy's coord, but it didn't work...)

Falck

Where did you get a trajectory for SMART-1 from?

Adam,

"It works fine for me".

I've found it easiest to start with something simple that works, and then modify it until it looks just the way I want.

Here's the DSC file I used:

and here's what it looks like from the Earth with the magnification turned up:

(as usual, this links to a larger image)
and here's a Cel://URL for this viewpoint:
cel://Follow/Sol:Earth/2003-10-24T16:39:16.17176?x=+Bzu/yMq1CrLDA&y=A0zxCSJb+f///////////w&z=ji1aYswYHPP3/////////w&ow=-0.027545&ox=-0.001332&oy=0.998453&oz=0.048276&select=gcenter&fov=1.407382&ts=1.000000<d=0&rf=13279&lm=16

Note that it is important to specify appropriate Axis and Angle values so that the model will be face-on to the observer. I use Grant's spreadsheet http://www.lns.cornell.edu/~seb/celestia/hutchison/spreadsheets.html to get initial values and then use Celestia's builtin adjustment tool to get the orientation exactly right.

I've made a list of the most common add-on problems and solutions at http://www.lns.cornell.edu/~seb/celestia/addon-intro-p6.html


Does this help?

I got all the numbers right I think (used out galaxy's since it's at it's center) but the difference is I tried to make a 3d object exist at the center. Mine said "Mesh "blackhole.3ds" and I was trying to get this cool model that I downloaded of a spinning black hole with disk to appear. How come only your example works, not 3d objects?

Adam,

I'm guessing you're trying to modify the black hole addon made by Jorge Sobrino. I'm afraid it's a case of "you can't get there from here."

Unfortunately, he designed it before DSC files were available. It can only be used as a "fake planet" orbiting a star. (It doesn't specify the name of the surface texture file within the 3DS model so it has to be specified as a Texture in an SSC file.) Planets can only be seen if you're within a light year of the star they're orbiting. And stars can only be seen if they're within 16K light years of the sun

Just now I tried using Anim8or to apply a file as a surface texture and I couldn't persuade it to do it. It looks like someone will have to design another black-hole model from scratch for use as a Nebula object.

Sorry.

JackHiggins wrote:Falck

Where did you get a trajectory for SMART-1 from?

Jack, as I said, it wasn't SMART-1, but another low-thrust trajectory. I'm a mission/systems analyst at NASA, specializing in low-thrust trajectories, so I have have various low-thrust trajectories that I've tried visualizing in Celestia. Hence the reason most of my posts tend to be about getting more mission visualization features in Celestia.

FYI while I'm posting here I represent only myself and not NASA

Falck wrote:Jack, as I said, it wasn't SMART-1, but another low-thrust trajectory...

Whoops... Didn't read that carefully enough...

So- (if you don't mind me asking!) Which spacecraft trajectories are you using? Any idea if they'd be available to the general public (ie celestia users) any time soon?!

JackHiggins wrote:Whoops... Didn't read that carefully enough...

So- (if you don't mind me asking!) Which spacecraft trajectories are you using? Any idea if they'd be available to the general public (ie celestia users) any time soon?!

None of the missions Im working on are publicly available yet, either because the designs havent been finalized, or because theyre being studied for technology development purposes only.

However, I think the trajectory for Deep Space 1 is publicly available in Spice format at the NAIF ftp site.