Celestia Forums

Hello all,
I have seen in script for creating a mars axis
cmod_axis.zip
found here
http://www.lns.cornell.edu/~seb/celesti ... les.html#5
the script line:

Radius 5e3

was used.
can someone explain to me what the 5e3 means. I think its obviously a measurement for distance I think.
What might this number mean for example if this radius is compared to the radius of mars?
I want to create axis for other planets but this number in script confuses me.
thanks
steve

ncc1701d wrote:Hello all,
I have seen in script for creating a mars axis
cmod_axis.zip
found here
http://www.lns.cornell.edu/~seb/celesti ... les.html#5
the script line:

Radius 5e3

was used.
can someone explain to me what the 5e3 means. I think its obviously a measurement for distance I think.
What might this number mean for example if this radius is compared to the radius of mars?
I want to create axis for other planets but this number in script confuses me.
thanks
steve

Steve,

this is the scientific/computer notation for (big) numbers:

e1 = 10
e2 = 100
e3 = 1000
...
what is e4 my friend??

Hence 5e3 = 5000

what is 5.3245e3 ??

F.

I hope I get this right

Is it 5324.5?

Thanks for you help. I had a hunch it was scientific notation but its been long time since I had math class.

One thing to bear in mind is that the Addon was created for an older version of Celestia before the new orbit and rotational frames were available. As a result, its catalog file had to include orbit and orientation values matching those of the parent body.

When using Celestia v1.5.0 or later, it can be more easily adapted for use with other objects by specifying that its coordinate systems be relative to the parent body.



p.s. You don't have to use scientific notation for the Radius value, of course.
Radius 5000
would have done just as well. For some reason, I didn't feel like typing 3 zeroes that day.

p.p.s.
And don't forget that Celestia built from svn includes its own display of coordinate systems' axes, which might be more appropriate for your purposes.

ncc1701d wrote:Is it 5324.5?

Good job! You are correct.

It's very easy, the number after the e is the number of positions you have to shift the dot (.) to the right. If the number is negative you should shift the dot to the left.
So:

3e3 = 3.0e3 = 3000.0
3e-3 = 3.0-3 = 0.003