Birth location of an object changes with different time ranges about galpy HOT 1 CLOSED

Hi!

The first entry in the time array is the time of the initial condition (that is, the initial condition isn't assumed to be at t=0, which I think you may have thought). So because you change the initial time, your clage will be a different time in the past. If you keep the initial times the same, e.g., in your second run use

ts = np.linspace(-200.0, 100.0, 10001)#*u.Gyr

then you'll see that you get a consistent result.

A few more comments:

• You do have to add *u.Gyr if you want your times to be interpreted as being in Gyr. Without this, the times are assumed to be in internal units. Given how you define clage, I think this is supposed to be in Gyr.
• I think you want to integrate backwards in time, but you are integrating forwards in time. For your purposes, the best thing to do would be to use

  ts = np.linspace(0,-clage, 10001)
  

  So you go from the present (defined to be t=0 here) to the time you want to integrate backwards for.

I hope this helps!

from galpy.