AttributeError: 'Antenna' object has no attribute 'observer'

[nhurleywalker]

I'm attempting to run astrokat-targets.py to find a gain calibrator:

tash@GLaDOS:~$ python3 /usr/local/bin/astrokat-targets.py --target src 00:01:00 -01:00:02.31
Traceback (most recent call last):
  File "/usr/local/bin/astrokat-targets.py", line 4, in <module>
    __import__('pkg_resources').run_script('astrokat==0.1.dev773+master.3ca200e', 'astrokat-targets.py')
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 658, in run_script
    self.require(requires)[0].run_script(script_name, ns)
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 1438, in run_script
    exec(code, namespace, namespace)
  File "/usr/local/lib/python3.6/dist-packages/astrokat-0.1.dev773+master.3ca200e-py3.6.egg/EGG-INFO/scripts/astrokat-targets.py", line 1077, in <module>
    outfile=args.outfile,
  File "/usr/local/lib/python3.6/dist-packages/astrokat-0.1.dev773+master.3ca200e-py3.6.egg/EGG-INFO/scripts/astrokat-targets.py", line 856, in main
    observatory = Observatory()
  File "/usr/local/lib/python3.6/dist-packages/astrokat-0.1.dev773+master.3ca200e-py3.6.egg/astrokat/observatory.py", line 62, in __init__
    self.observer = self.get_observer(horizon=horizon)
  File "/usr/local/lib/python3.6/dist-packages/astrokat-0.1.dev773+master.3ca200e-py3.6.egg/astrokat/observatory.py", line 149, in get_observer
    observer = self.kat.observer
AttributeError: 'Antenna' object has no attribute 'observer'

The error seems to be a fault in the instantiation of the Observatory() class? I'm not sure how to fix this.

[ajoubertza]

Hi @nhurleywalker

That looks like a problem with the version of katpoint you have installed. katpoint < 1.0 still has an observer attribute on the katpoint.Antenna objects. Do you maybe have katpoint 1.0a1 installed? You could try with katpoint 0.10. The older versions of katpoint still use ephem, instead of astropy.

We should probably update astrokat to be compatible with both.

[nhurleywalker]

To install the code, I cloned it from github and ran

python setup.py install

So if it has an outdated version of katpoint then it got that from the setup command. I see in the docs you actually recommend using pip to install directly from github, so I wonder if I had done that whether it would have worked properly. Tomorrow I'll see if I can test this or at least review the logs to see where it got katpoint from when it installed. Thanks for the prompt reply!

[ajoubertza]

@nhurleywalker Yes, I tried python setup install and pip install . and got different results. The setup method get the pre-release of katpoint, 1.0a1, while pip method gets katpoint 0.10. Anyway, the setup.py has now been updated to limit the katpoint version, so both methods should work.

Please confirm when you have a working installation so that we can close this issue.