Units in gravlens/lensmodel
The important dimension in gravlens/lensmodel is length. I usually
think in terms of angular variables, but for the most part the
length units are arbitrary. Before using the code, you should
choose your favorite units (arcseconds, or Einstein radius units,
or whatever). If you express all lengths in those units,
everthing should be fine.
The one exception is when you model time delays to constrain the
Hubble constant. Then you need:
- positions in arcseconds
- time delays in days