11.1 Introduction to SHA Application Program Interface (API)
The VAO is the Virtual Astronomical Observatory, and protocols compatible with the VAO require an interface to the SHA that can be accessed via programs running on other servers, or an application program interface (API).
The SHA data can be accessed via an HTTP GET program interface where the request is a set of parameter=value pairs and what is returned is an IPAC Table containing metadata and URL links to download products with the related ancillary files. This page describes these input parameters and the columns returned.
Currently, only the image data are available via the API. Spectra will be available in a future SHA version.
The input parameters are entered as standard HTTP parameter=value pairs in HTTP/GET syntax. In this syntax, the parameter name is followed by an “equals” sign (=) which is then followed by a value. No extra spaces are allowed, and if the value contains any spaces or special characters that might be ambiguous, they have to be encoded formally as in any HTTP or URL reference (more discussion here). As shown above, each component of a pair is separated from the other by an ampersand (&) character.
DATASET
Data set. Two sets are supported: ivo://irsa.ipac.spitzer.level1 (BCD data) ivo://irsa.ipac.spitzer.level2 (PBCD data)
VERB
Verbosity level, controls the number of columns in the output. 1 - selected columns, 3 - all available
RA
Search by position: right ascension in degrees
DEC
Search by position: declination in degrees
SIZE
Search by position: region size in degrees
NAIFID
Search by moving target: NAIF ID, which is a unique number allocated to solar system objects (e.g. planets, asteroids, comets, spacecraft) by the NAIF at JPL.
PID
Search by program: program ID
REQKEY
Search by AOR ID: Astronomical Observation Request ID
11.4 Output columns
The output columns in the resultant table describe metadata and include a link to download the requested data product and the important ancillary products related to it. Please note that all output columns are available only when verbosity level is set to 3.
reqkey
AORKEY
Spitzer Astronomical Observation Request Number
pbcdid
pBCD ID
Post Basic Calibrated Data ID (Level 2 product search)
bcdid
BCD ID
Basic Calibrated Data ID (Level 1 product search)
accessUrl
Product access reference URL
The URL to be used to retrieve image or table, "NONE" if product does not have public access
AccessWithAnc1Url
Zip access reference URL
The URL to be used to retrieve the image or spectra with important ancillary products (mask, uncertainty, etc.) as a zip archive, "NONE" if product does not have public access
modedisplayname
Instrument/Mode
Instrument/Mode
wavelength
Bandpass
Bandpass ID
cra
RA (J2000)
Right Ascension in sexigesimal format HHMMSS J2000, of the FITS image. Example: "2h23m14.3s"
cdec
Dec (J2000)
Declination in sexagesimal format DDMMSS J2000, of the FITS image. Example: "-12d43m11s"
exposuretime
Exposure time in seconds
Exposure time (Level 1 products only)
primary
Primary field
If this value is equal to 1, then the product has primary scientific value (Level 1 products only)
filetype
Table or Image
Table or Image
externalname
File name
File name
ptcomment
Product description
Product description
ra
Crval1 in FITS file
Right Ascension in Equatorial J2000 for the center of the FITS image
dec
Crval2 in FITS file
Declination in Equatorial J2000 for the center of the FITS image
epoch
Epoch
Epoch year
equinox
Equinox
Precessional year associated with the coordinate system
begintime
Observation start
Observation start (Level 2 products only)
endtime
Observation end
Observation end (Level 2 products only)
scet
Spacecraft event time: the coordinated universal time on board the spacecraft
Date and time of data collection event (Level 1 products only)
minwavelength
Min. wavelength (microns)
Min. wavelength (microns)
maxwavelength
Max wavelength (microns)
Max wavelength (microns)
filesize
File size in bytes
File size in bytes
campid
Campaign ID
Instrument Campaign ID
ra1
RA of corner 1
RA position of the lower left image corner [pixel space, where first pixel is located at (0.5, 0.5), position (ra1, dec1) = (0.5, 0.5)]
dec1
Dec of corner 1
DEC position of the lower left image corner [pixel space, where first pixel is located at (0.5, 0.5), position (ra1, dec1) = (0.5, 0.5)]
ra2
RA of corner 2
RA position of the lower right image corner [pixel space, where first pixel is located at (0.5, 0.5), position (ra2, dec2) = (NAXIS1 + 0.5, 0.5)]
dec2
Dec of corner 2
Dec position of the lower right image corner [pixel space, where first pixel is located at (0.5, 0.5), position (ra2, dec2) = (NAXIS1 + 0.5, 0.5)]
ra3
RA of corner 3
RA position of the upper right image corner [pixel space, where first pixel is located at (0.5, 0.5), position (ra3, dec3) = (NAXIS1 + 0.5, NAXIS2 + 0.5)]
dec3
Dec of corner 3
Dec position of the upper right image corner [pixel space, where first pixel is located at (0.5, 0.5), position (ra3, dec3) = (NAXIS1 + 0.5, NAXIS2 + 0.5)]
ra4
RA of corner 4
RA position of the upper left image corner [pixel space, where first pixel is located at (0.5, 0.5), position (ra4, dec4) = (0.5, NAXIS2 + 0.5)]
dec4
Dec of corner 4
Dec position of the upper left image corner [pixel space, where first pixel is located at (0.5, 0.5), position (ra4, dec4) = (0.5, NAXIS2 + 0.5)]
naxis1
naxis1
The size of the image in pixels for dimension 1
naxis2
naxis2
The size of the image in pixels for dimension 2
cdelt1
cdelt1
The pixel scale (in degrees on the sky per pixel) at the reference location for dimension 1
cdelt2
cdelt2
The pixel scale (in degrees on the sky per pixel) at the reference location for dimension 2
crota2
crota2
The rotation angle from the "up" direction to the celestial pole
crpix1
crpix1
The pixel coordinate of the reference location (can be fractional, in the image center or off the image) for dimension 1
crpix2
crpix2
The pixel coordinate of the reference location (can be fractional, in the image center or off the image) for dimension 2
crval1
crval1
[deg] RA at CRPIX1, CRPIX2
crval2
crval2
[deg] Dec at CRPIX1, CRPIX2
ctype1
ctype1
The coordinate system (first four characters) and WCS map projection (last three characters) for dimension 1
ctype2
ctype2
The coordinate system (first four characters) and WCS map projection (last three characters) for dimension 2
11.5 Response on error
If an error occurs when an HTTP request is being processed, an empty IPAC table with a single attribute, named ERROR, will be returned. Error message is a value of this attribute.
