Hi Irina,

To retrieve an IDL system variable such as !DTOR or !CONST, you can use the Python getattr() method:

>>> from idlpy import *
>>> getattr(IDL, "!dtor")
0.017453292

>>> const = getattr(IDL, "!const")
>>> const.keys()
dict_keys(['ALPHA', 'AU', 'C', 'DTOR', 'E', 'EPS0', 'EULER', 'F', 'G', 'GN', 'H', 'HBAR', 'I', 'K', 'LY', 'M_EARTH', 'M_SUN', 'ME', 'MN', 'MP', 'MU0', 'N0', 'NA', 'P0', 'PARSEC', 'PHI', 'PI', 'R', 'R_EARTH', 'RTOD', 'RE', 'RYDBERG', 'SIGMA', 'T0', 'U', 'VM'])
>>> const['PARSEC']
30856775814671912.0

Good luck!