Goddard Utilities (pydl.goddard)

Introduction

This package provides functionality similar to the The IDL® Astronomy User’s Libary, sometimes called the “Goddard Utilities”, maintained by Wayne Landsman and distributed with idlutils.

In general, functions that are needed by pydl.pydlutils or pydl.pydlspec2d are implemented, while functions that are not needed have much lower priority.

The Goddard package is itself divided into a number of subpackages. Below we list the subpackages and the usability of the PyDL equivalent. The readiness levels are defined as:

Obsolete

No point in implementing because the purpose of the code lapsed many years ago.

Not Applicable (NA)

No point in implementing because another built-in or numpy/scipy/astropy package completely replaces this.

None

Not (yet) implemented at all.

Rudimentary

Only a few functions are implemented.

Fair

Enough functions are implemented to be useful, but some are missing.

Good

Pretty much anything you could do with the Goddard code you can do with the equivalent here.

Subpackage	Readiness Level	Comments
astro	Rudimentary	General astronomical utility functions.
astrom	NA	Tools for manipulating WCS data in FITS headers. Use astropy.io.fits and astropy.wcs.
coyote	NA	The Coyote library for plotting and graphics developed by David Fanning.
database	None	Allows access to IDL-specific databases.
disk_io	None	Provides access to IRAF image (.imh) files and AJ/ApJ-style tables.
fits	NA	Use astropy.io.fits.
fits_bintable	NA	Use astropy.io.fits.
fits_table	NA	Use astropy.io.fits.
idlphot	None	Adapted from an early version of DAOPHOT.
image	None	Generic image processing functions, including convolution/deconvolution.
jhuapl	None	Functions from the JHU Applied Physics Lab.
markwardt	None	Levenberg-Marquardt least-squares minimization.
math	Rudimentary	Generic mathematical functions. Many are implemented in numpy or scipy.
misc	Rudimentary	General utility functions that do not involve astronomy specifically.
plot	NA	Functions that supplement the built-in IDL plotting capabilities.
robust	None	Robust statistical fitting procedures.
sdas	None	Provides access to STDAS/GEIS image files.
sockets	NA	Functions for performing web queries in IDL. Use astroquery.
structure	NA	Tools for manipulating IDL data structures. Use numpy.recarray.
tv	NA	Functions for manipulating IDL image displays.

API

pydl.goddard Package

This subpackage contains the Goddard utilities.

pydl.goddard.astro Module

This module corresponds to the goddard/astro directory in idlutils.

Functions

airtovac(air)	Convert air wavelengths to wavelengths in vacuum.
gcirc(ra1, dec1, ra2, dec2[, units])	Computes rigorous great circle arc distances.
get_juldate([seconds])	Returns the current Julian date.
get_juldate_main()	Entry point for the get_juldate command-line script.
vactoair(vacuum)	Convert vacuum wavelengths to wavelengths in air.

pydl.goddard.math Module

This module corresponds to the goddard/math directory in idlutils.

Functions

flegendre(x, m)

Compute the first m Legendre polynomials.

pydl.goddard.misc Module

This module corresponds to the goddard/misc directory in idlutils.

Functions

cirrange(ang[, radians])

Convert an angle larger than 360 degrees to one less than 360 degrees.