pyoof is a Python pacakge which performs out-of-focus (OOF) holography on astronomical beam maps for single-dish radio telescopes.
pyoof is a Python package that contains all needed tools to perform out-of-focus (OOF) holography on astronomical beam maps for single-dish radio telescopes. It is based on the original OOF holography papers,
- Out-of-focus holography at the Green Bank Telescope
- Measurement of antenna surfaces from in- and out-of-focus beam maps using astronomical sources
The pyoof package calculates the aperture phase distribution map from a set of beam maps (telescope observations), at a relatively good signal-to-noise as described by B. Nikolic. By using a nonlinear least squares minimization, a convenient set of polynomials coefficients can be found to represent the aperture distribution. Once this is calculated the aberrations on the primary dish are known.
We are currently testing the pyoof package at the Effelsberg radio telescope :satellite:.
pyoof is still in the early-development stage. While much of the functionality is already working as intended, the API is not yet stable. Nevertheless, we kindly invite you to use and test the library and we are grateful for feedback. Note, that work on the documentation is still ongoing.
The easiest and more convenient way to install the pyoof package is via pip
pip install pyoof
The installation is also possible from the source. Clone the GitHub repository and execute!
python setup.py install
From the source you can install developer versions, be aware of that. I believe in the future :smile:, so please install Python 3. Unfortunately, a windows version of the package is currently not available.
So far the pyoof package uses the common Python packages, it is recommended to install the anaconda distribution first, although using pip is also fine.
pyoof has the following strict requirements:
- Python 3.5 or later
- setuptools: Used for the package installation.
- NumPy 1.11 or later
- SciPy: 0.15 or later
- astropy: 1.3 or later (2.0 recommended)
- pytest 2.6 or later
- matplotlib 1.5 or later: To provide plotting functionality.
- PyYAML 3.11 or later.
For future versions dependencies will be reduced.
To use the pyoof package is straight forward. First define your observational data in the established fits file format and then execute!
import pyoof from pyoof import aperture, telgeometry # Extracting observation data and important information oofh_data = 'path/to/file.fits' # fits file with special format data_info, data_obs = pyoof.extract_data_pyoof(oofh_data) # Effelsberg telescope definition effelsberg = [ telgeometry.block_effelsberg, # Blockage distribution telgeometry.opd_effelsberg, # OPD function 50., # Primary dish radius 'effelsberg' # Telescope name ] pyoof.fit_beam( data_info=data_info, # information data_obs=[beam_data, u_data, v_data], # observed beam method='trf', # opt. algorithm 'trf', 'lm' or 'dogbox' order_max=5, # it will fit from 1 to order_max illum_func=aperture.illum_pedestal, # or illum_gauss telescope=effelsberg, # telescope properties resolution=2 ** 8, # standard is 2 ** 8 box_factor=5, # box_size = 5 * pr, pixel resolution )
For the impatient :hushed: , see the Jupyter notebook example, oof_holography.ipynb.
pyoof is licensed under a 3-clause BSD style license - see the LICENSE.rst file.
If you have any questions about the code or theory sections, do not hesitate and raise an issue. You can also send me an email directly:
- tcassanelli _at_ gmail.com