Celestia Forums

Hi everyone:

I have been developing educational activities for Celestia that draw new textures to replace existing ones at some point in the Celestia future. For example, in the year 9998, I have a new giant sun drawn (a big Red Giant) that takes up the volume of most of the inner solar system. The Red Giant Sun is simply a planet that uses emissive true and is centered on the existing Sol, with a radius of over 1 au. In order to draw it only after the year 9998, I have inserted a Beginning command in its ssc file. It works fine and does not appear until 9998. However, to my dismay, Celestia still treats it as if it was present, although invisible, in our present time. For example, when I try to select the Sun or Mercury or Venus with a left mouse click in the year 2003, all I select is the Red Giant Sun (since it will have enveloped the inner planets). Celestia is not drawing it until the proper time in 9998, but assumes it is in space at that spot, even before the ""Beginning" date and is allowing me to select it (even if I don't want to).

Other objects I have placed in the future also suffer the same problem. For example, in the year 9999, I "end" the current planet Jupiter with an Ending command in the solar.ssc file and start a new, changed Jupiter (to reflect the presence of a Red Giant sun nearly), 1 second later, using a Beginning command. Again, it works fine and does not appear drawn until the prescribed time, but when I click on Jupiter in the year 2003, I get either Jupiter or the New Jupiter selected, even though the new Jupiter is not supposed to be there yet.

Is there something I can do about this, short of dragging all the Activity add-on files out of the extras files when I'm not using it?

Frank

I get this too a lot, with beginning and ending dates for old spacecraft missions.

AFAIK, you can't do anything yet (in the current version) but it might be a small feature request for 1.3.1final, or 1.3.2pre1? If you can make class "invisible" objects non-selectable, it shouldn't be that hard to do it for objects with an ending date too...?

This was not by design . . .

The fix was easy, and it will be in 1.3.1 final.

--Chris

Thats good new Chris.
Looking forward to the new release.

But:.....
What about the option to forward or reverse time to view the object that is not available at that time.

Nice! What happens if you press enter & type in the name? Will it still appear, or is it a different colour etc..?

Will this also apply to "invisible" objects?

Also how will the "Go To" command be affected?

Can anyone here confirm that this was indeed fixed in 1.3.1 final?

Thanks!

-Don G.

Don, it looks fixed to me.

Frank

Don, et al.,

It isn't at all obvious to me what problem you're asking about.

FWIW, with today's date, Celestia v1.3.1-1 lets you Select and GoTo Mir. It also draws Mir's orbital path and a marker.

Mir's label and model aren't drawn, though.

Selden

What the others are talking about is something like this... I'll use cassini as an example. I've made 2 models, one of which shows it with huygens attached, and one after its deployment. One of these models dissapears at the appropriate time, and is instantly replaced with the next model.

I give them different names, so I can tell when one is replaced, without having to go and look at it. Since they're both in the same place, in older versions of celestia you could click on the location, and there was a 50/50 chance you would select the version that was no longer visible.

Or say if you had an earth orbit really crowded with objects, and you wanted them all to dissapear at a certain time. Previously, after they all dissapeared, you could still click somewhere in earth orbit, and select one of the now "invisble" objects.

Jack,

Thanks for the clarification.

You can no longer "Select with mouse click" an object past its Ending date.
However, you still can select it by name and see its marker and orbit. My example above shows this effect with Mir.

Thank you gents.

selden wrote:However, you still can select it by name and see its marker and orbit. My example above shows this effect with Mir.

Hmmm, would you all consider this to be a bug, that could create problems? Or is this of some good use?

-Don G.

don,

This issue has an up side and a down side.

The up side: Yesterday I wanted to take a screenshot of Salyut 7, for a new thing that I want to do on my website. Instead of having to go to earth and run time back to 1991 to see if I had it installed, I was able to just hit enter, and type in "Salyut". Nothing came up, so I knew that I had to exit out of celestia, and copy the files for that spacecraft over from the pre11 folder (this was all happening in 1.3.1final). Then I restarted, and took the screenshot that I wanted.

The down side:
When you've got a spacecraft which cycles through various models, like Galileo/Cassini/Vega etc, you get the same name coming up twice when you hit Enter and search for it. If there was some way of specifying in an ssc file "these two/three/forty items should be listed as ONE" , it would solve a LOT of problems.

I consider it to be a low priority bug.

As someone else already mentioned, it seems to me that it would be appropriate for Celestia to have some way to display the Beginning and Ending dates of objects, along with a quick way to get to those time intervals. Searching SSC files and using the "set time" menu to see them is awkward.

This bug partially compensates for that lack.

Okay, it sounds like this is more of a "fine tuning" issue.

Thank you gents.

-Don G.

selden wrote:As someone else already mentioned, it seems to me that it would be appropriate for Celestia to have some way to display the Beginning and Ending dates of objects, along with a quick way to get to those time intervals

Optional Julian date display would be nice too...