While in the tcsh shell environment (astronomy's default shell for all users) you are able to activate python via:

conda activate py3

This will activate the py3 conda environment on astronomy. You can confirm this is the case with the command:

which python

Which will show you the current version of python being used and the location of the conda environment.

For example:

[user@astronomy ~]$ conda activate py3
[user@astronomy ~]$ which python
/home/local/Anaconda3-2020.02/envs/py3/bin/python
[user@astronomy ~]$ python
Python 3.7.7 (default, May  7 2020, 21:25:33) 
[GCC 7.3.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>