fractions of a second

rthorvald · Post #1by **rthorvald** » 29.05.2005, 23:48

I just found out that Celestia does not seem to understand fractions of a second in julian.

After using all day to line up jestr??s Huygens XYZ file with the landing coordinates, i finally have the free flight model intersecting the landed version quite nicely, but it happens between two ticks of the clock, so it seems to be impossible to switch them at the exact moment... Not a big deal perhaps, but the probe goes down so fast, one has to slow down time to see the impact. And so it is *very* noticeable; the free flight model goes hundreds of meters past before Celestia hides it and brings the landed version up!

Any ideas for a workaround? Or is my Celestia perhaps buggy?

Thanks,
rthorvald

Post #2by **selden** » 30.05.2005, 00:36

Well, maybe you could cheat and set the last xyz value to be the landing location.

rthorvald · Post #3by **rthorvald** » 30.05.2005, 05:02

selden wrote:Well, maybe you could cheat and set the last xyz value to be the landing location.

Thanks for the suggestion, but doing that doesn??t really help; i still need to switch the models at the correct time...

-rthorvald

TERRIER · Post #4by **TERRIER** » 01.06.2005, 18:58

rthorvald wrote:
selden wrote:Well, maybe you could cheat and set the last xyz value to be the landing location.

Thanks for the suggestion, but doing that doesn??t really help; i still need to switch the models at the correct time...

-rthorvald

I'm not entirely sure, but would inserting this "correct time" (along with appropriate xyz co-ords) into the xyz file, then enable it to be recognised by the .ssc file ?

jestr · Post #5by **jestr** » 02.06.2005, 00:07

It might,but there is a limit to the accuracy of the xyz coordinates in Celestia.There are certain parts of space that cannot be plotted in xyz coordinates in Celestia-the fractions are rounded up or down.I'm not sure if the gaps get larger the further from the origin you are,I have found it easier to pinpoint closer in towards the sun.Also Celestia's orbits drawn from the xyz points are not always a smooth curve so often the object will overshoot the coordinate before retracting back sharply.If you could find a point on the XYZ coordinate 'grid' where it intersects Titan-close to the landing site,you could move the landing site here,and it could work.Jestr

rthorvald · Post #6by **rthorvald** » 03.06.2005, 18:23

TERRIER wrote:I'm not entirely sure, but would inserting this "correct time" (along with appropriate xyz co-ords) into the xyz file, then enable it to be recognised by the .ssc file ?

Good idea, it??s worth a try...

jestr wrote:If you could find a point on the XYZ coordinate 'grid' where it intersects Titan-close to the landing site,you could move the landing site here,and it could work.Jestr

Yes, i considered this... But i don??t want to move the site. Then it??s better to let it stay the way it is.

Anyway, thanks for all your suggestions. I??ll continue to play with it, maybe something will turn up.

-rthorvald