Celestia Forums

Hi All,

Well Im very new to celestia, but extremley impressed. Now I know its meant as more of a solar
system explorer than a satellite tracker, but I could really do with some help to do the following

1) Create a view of a Single earth satellite showing The Earth, The Satellite (eg ISS), and the
Satellite's Orbit. I can show the satellite and earth in one shot, with a little effort, but when showing
orbits it (appears) to show multiple bodies' orbits. Anyone have any idea on hjow to show exactly
one object's orbit

2) Showing the view of the earth from the Satellite. I guess I need to dig into the scripting
commands a little deeper in order to get this to work. Related Question: Is there anyway to
show the satellite footprint ?

3) Is there a way, once a scene has been setup interactively, to get celestia to create a script
of that scene ?


(And apologies if these are all silly questions, Im still very new to celestia, I did read thru the
docs before posting here, but didnt really find anything that helped me - Thats not to say I
didnt manage to miss it, or read enough)

Howdy irp, and welcome to Celestia!

irp wrote:1) Create a view of a Single earth satellite showing The Earth, The Satellite (eg ISS), and the Satellite's Orbit.

Unfortunately, objects like ISS, Hubble, etc. do not have a display orbit option. I could have sworn they did at one point, but not in the current 1.3.1 CVS version. Can someone tell me if it was just a dream <grin>?

In addition, the selection of individual object orbits is not available either. However, this has been requested for a future version.

irp wrote:2) Showing the view of the earth from the Satellite.

Select the ISS, 'g'oto it, then manipulate the view (right mouse drag, Home and End keys), and the Field of View (FOV - '.' and ',').

irp wrote:Is there a way, once a scene has been setup interactively, to get celestia to create a script of that scene?

Use the Bookmark menu to save the scene and recall it later. You can also press Ctrl+Ins or Ctrl+c to save a Cel://URL to the clipboard. A Cel://URL is a bunch of text data to re-create a scene, which can then be pasted into a HTML page or saved as text and then added to a script via the seturl command.

If you would like to learn more about scripting, there is a guide here: http://www.donandcarla.com/Celestia/.

Hope this helps some <smile>.

-Don G.

DonG wrote:Unfortunately, objects like ISS, Hubble, etc. do not have a display orbit option. I could have sworn they did at one point, but not in the current 1.3.1 CVS version. Can someone tell me if it was just a dream <grin>?

There is a "Spacecraft" orbit rendering checkbox in Celestia v1.3.1pre11 for Windows.

selden wrote:There is a "Spacecraft" orbit rendering checkbox in Celestia v1.3.1pre11 for Windows.

Yes, and I tried this with Chris' latest release candidate but it did not show the ISS or Hubble orbits. Do you see them with this checked?

-Don G.

DonG wrote:Yes, and I tried this with Chris' latest release candidate but it did not show the ISS or Hubble orbits. Do you see them with this checked?

Yes.
They're grey.
(Of course, the "orbit" box also has to be checked.)

Added slightly later:
Don't forget that they're drawn "behind" the Earth and don't necessarily come very close to the satellites, so they won't be in the field of view in many circumstances.
Added even later:
Also there certainly are bugs (as opposed to design problems) in how orbits are drawn. Pre11 doesn't seem to draw the ISS orbit unless the observer's location is more than about 3,300 km away from the ISS. If you're closer than that, only part or even none of the orbit may be drawn in Celestia's window.

Howdy Selden,

Actually, the orbit of a selected object is red <smile>.

I now see that it is required to show Planet Orbits in order for the Spacecraft orbits to display. When Planet Orbit is not selected and Spacecraft is, the Spacecraft orbits are not displayed.

If you and/or anyone else can confirm this, I'll add a post to the Bugs forum.

-Don G.

Don,

After playing with Celestia v1.3.1pre11 for a while my conclusion is that orbits are drawn for spacecraft which orbit a planet if and only if that planet's orbit is being drawn. I'm not sure if this is intentional (a design problem) or unintentional (a bug). It certainly is confusing.

The following assume that both "show orbits" and "show spacecraft orbits" are enabled.

The orbit of a particular planet is drawn in at least two different circumstances.

1) If "show planet orbits" is enabled, all planet orbits are drawn in blue and the orbits of all the spacecraft orbiting all the planets are drawn in grey. If you select a spacecraft, its orbit is drawn in red.

2) If "show planet orbits" is disabled but a planet is selected, its orbit is drawn in red. The orbits of the spacecraft orbiting that particular planet are drawn in grey. The orbits of the spacecraft orbiting unselected planets are not drawn.

So, if "show planet orbits" is disabled and you select a spacecraft orbiting around a selected planet, the planet becomes deselected, the grey satellite orbits are turned off, and the red "selected" satellite orbit does not appear. I suspect this is what is happening to you.

The orbits of the spacecraft orbiting the sun continue to be drawn in grey whether or not any planet orbits are enabled.

Yes, that is a tad confusing. Making it even more confusing is the fact that spacecraft orbits are only drawn behind and to the sides of a planet. Oh well.

-Don G.

Selden,

Isn't this also true of orbits for natural satellites (moons)? They're visible only if the primary's orbit is visible?

- Hank

Hank,

Yes. It applies to moons, too.