Celestia Forums

Posted: **12.12.2017, 16:06**

Can someone provide an example of a working script for this?

I was thinking it could be done by

setting initial number to 1 and cycling through all the stars in celestia:getstar()
using celestia:getobserver():gedistanceto() star
use an if statement to decide whether to mark, i.e. whenever the distance is smaller than 40 million millionths of a light year
increment the star number by one and repeat until it reaches 120404

or

set celestia:setstardistancelimit(40)
cycle through stars in celestia:getstar()
if star:visible() is true then mark it
increment star number by one until 120404

Posted: **14.12.2017, 03:02**

Here's a CELX script that selects all the stars in a radius of 100 LY, relative to your current stellar selection. You can easily edit it to your taste and needs :

Code: Select all

-- Title: All stars inside a sphere of radius 100 LY, centered on your current selection.
-- Mark all stars in a sphere centered on the current selection. 

function mark_star_dist(obj, radius) 
   for star in celestia:stars() do 
      if star:getposition():distanceto(obj:getposition()) <= radius then 
         star:mark("yellow", "disk", 1, 1) 
      end 
   end 
end 

celestia:unmarkall() 
objname = "" 
obj = celestia:getselection() 

-- Radius of the sphere (in km): 
radius = 9.46e14 

while true do 
   obj = celestia:getselection() 
   if obj and objname ~= obj:name() then 
      objname = obj:name() 
      celestia:unmarkall() 
      mark_star_dist(obj, radius) 
   end 
   wait(0) 
end

Save this code in a text file, with the extension .celx, and enjoy!

Posted: **14.12.2017, 07:46**

When I saw your code I started wondering why I assumed that star in celestia:stars() can't be used here; and went around the world via the approaches I've mentioned instead.

I modified your code to be able to reduce marking down to the stars in between two distances from the selection; 99 and 101 light years from Altair for example. To achieve the result in the thread title, radius1 needs to be set to 0 and radius2 to 40

Code: Select all

-- Title: Mark all stars inside the difference between two spheres of radius 30 and 40 LY, centered on your current selection.

function mark_star_dist(obj, radius1, radius2) 
   for star in celestia:stars() do 
      if star:getposition():distanceto(obj:getposition()) > radius1 and radius2 >= star:getposition():distanceto(obj:getposition()) then 

         --star:unmark()
         star:mark("ffffff", "square", 9, 0.7, star:name(), true) 
      end 
   end 
end 

--celestia:unmarkall() 
objname = "" 
obj = celestia:getselection() 

-- Radius of the sphere (in ly / km_to_ly): 
radius1 = 30 / 0.00000000000010570 
radius2 = 40 / 0.00000000000010570

while true do 
   obj = celestia:getselection() 
   if obj and objname ~= obj:name() then 
      objname = obj:name() 
      mark_star_dist(obj, radius1, radius2) 
   end 
   wait(0) 
end

I've left celestia:unmarkall() commented out as to not counteract stacking
By commenting out star:mark(...) and removing the -- from star:unmark() one can swiftly undo previously made markings.

Celestia Forums

Mark all stars within a 40ly radius?

Mark all stars within a 40ly radius?