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 builtin 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 
coyote 
NA 
The Coyote library for plotting and graphics developed by David Fanning. 
database 
None 
Allows access to IDLspecific databases. 
disk_io 
None 
Provides access to IRAF image ( 
fits 
NA 
Use 
fits_bintable 
NA 
Use 
fits_table 
NA 
Use 
idlphot 
None 
Adapted from an early version of DAOPHOT. 
image 
None 
Generic image processing functions, including convolution/deconvolution. 
jhuapl 
None 

markwardt 
None 
LevenbergMarquardt leastsquares 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 builtin 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 
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¶

Convert air wavelengths to wavelengths in vacuum. 

Computes rigorous great circle arc distances. 

Returns the current Julian date. 
Entry point for the get_juldate commandline script. 


Convert vacuum wavelengths to wavelengths in air. 
pydl.goddard.math Module¶
This module corresponds to the goddard/math directory in idlutils.
Functions¶

Compute the first 
pydl.goddard.misc Module¶
This module corresponds to the goddard/misc directory in idlutils.
Functions¶

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