Optic

class gunagala.optic.Optic(aperture, focal_length, throughput, central_obstruction=<Quantity 0. mm>)

Bases: object

Class representing the overall optical system.

The optical system includes all optics (e.g. telescope, including any field flattener, focal reducer or reimaging optics) with the exception of optical filters, which are handled by the optical_filter.Filter class. At present only circular pupils (aperture) and are supported, but central obstructions (also circular) can be modelled.

Parameters:

aperture : astropy.units.Quantity

Diameter of the optical system entrance pupil (effective aperture diameter).

focal_length : astropy.units.Quantity

Effective focal length of the optical system as a whole.

throughput : astropy.table.Table or str

Optical throughput as a function of wavelength data, either as an astropy.table.Table object or the name of a file that can be read by astropy.table.Table.read(). The filename can be either the path to a user file or the name of one of gunagala’s included files. The table must use column names Wavelength and Throughput. If the table does not specify units then nm and dimensionless unscaled are assumed.

central_obstruction : astropy.units.Quantity, optional

Diameter of the central obstruction of the entrance pupil, if any. If not specified an unobstructed pupil is assumed.

Attributes:

aperture : astropy.units.Quantity

Same as parameters.

central_obstruction : astropy.units.Quantity

Same as parameters.

aperture_area : astropy.units.Quantity

Effective collecting are of the optical system aperture, including the effects of the central obstruction, if any.

focal_length : astropy.units.Quantity

Same as parameters.

focal_ratio : astropy.units.Quantity

Effective focal ratio (F/D) of the optical system

theta_range : astropy.units.Quantity

Pair of angles corresponding to the minimum and maximum angles of incidence in focal plane of the optical system. These can be used by optical_filter.Filter objects to calculate cone angle effects for focal plane filters. These are automatically calculated from the central obstruction and entrance pupil diameters and effective focal length assuming a telecentric output. If the optical system is far telecentricty these values should now be used.

wavelengths : astropy.units.Quantity

Sequence of wavelength values from the tabulated throughput data, loaded from throughput_filename.

throughput : astropy.units.Quantity

Sequence of throughput values from the tabulated throughput data, loaded from throughout_filename.