Getting Started =============== Dependencies ------------ The following Python package dependencies should be installed on your system. * ``numpy`` (required) * ``healpy`` (optional, for handling healpix maps) * ``astropy`` (optional, for updating internal IERS-A tables) Installation ------------ To use the latest version of QPoint, install via ``pip``:: $ pip install qpoint Otherwise, for developement work, clone the repository (``_) and install manually:: $ pip install . Or, if installing on a shared machine:: $ pip install --user . Examples -------- Several example scripts are provided in the `examples/ `_ directory. The script `example_point.py `_ shows some typical usage of the :py:class:`~qpoint.qpoint_class.QPoint` class, e.g. to construct timestreams in celestial coordinates from a set of local coordinates, and to compute offset detector pointing from a boresight location. The script `example_map.py `_ shows some typical usage of the :py:class:`~qpoint.qmap_class.QMap` class, e.g. to simulate detector timestreams with offset pointing from an input HEALpix sky realization, and to bin individual detector timestreams into a HEALpix map. Algorithms ---------- `This document <./qpoint.pdf>`_ describes the quaternion-based algorithm used for computing equatorial right ascension and declination from the local coordinates of the (potentially moving) observing platform, including the various approximations that can be made to speed up the calculation. The document also covers computing detector pointing offset from the telescope boresight, using the same quaternion formalism. `Another document <./mapmaking_hwp.pdf>`_ describes the mapmaking algorithm (implemented in the :py:class:`~qpoint.qmap_class.QMap` class) for projecting time-ordered data onto a `HEALPix `_ spherical coordinate grid to make sky maps of Stokes parameters, typically used by telescopes designed for observing the cosmic microwave background (e.g. `SPIDER `_).