gistfile1.py

from pyrap.measures import measures
import os
import sys
from io import BytesIO
from tempfile import SpooledTemporaryFile
from contextlib import contextmanager

@contextmanager
def redirect_stream(stream, destination):
    old_stream = os.dup(stream.fileno())
    with SpooledTemporaryFile() as s:
        os.dup2(s.fileno(), stream.fileno())
        yield
        s.seek(0)
        destination.write(s.read())
    os.dup2(old_stream, stream.fileno())

output_string = BytesIO()

dm = measures()
dm.frame_now()
with redirect_stream(sys.stderr, output_string):
    dm.separation(dm.direction("JUPITER"), dm.direction("SUN"))

print "Std error of pyrap was: "
print output_string.getvalue()