astropy/astropy — pull request #161 by nhmc (2012-02-10 23:20:42+00:00)
Title: adding info function to print available constants, plus extra constant values

Here are a couple of minor changes to the constants sub-package. I've added a few more useful values (Rydberg, eV, Jansky and Mpc) along with a function info() that returns a string with a quick summary of all the available constants in the si and cgs modules. I've also added these summaries to the si and cgs docstrings, so users can easily do, say:

```python
from astro.constants import cgs
cgs?
```

from ipython to see what values are available. There may be better ways to generate such a summary than with the info() function, any suggestions are welcome!

Cheers,
Neil