Building HTTP Get Queries
- HTTP GET Syntax
- Examples
- Instrument Parameters
- File Type Parameters
- Search Criteria Parameters
- URL-encoding Special Characters
HTTP GET Syntax
HTTP GET structure is useful for building a direct query to the web service without filling out the form
The general format of an HTTP GET query is:
[URL of program]?[keyword1=value1]&[keyword2=value2]&...[keywordn=valuen]
The URL to the KOA Data Access Service search executable is:
https://koa.ipac.caltech.edu/cgi-bin/KOA/nph-KOA
The following sections describes an example and possible keyword=value pairs, which are analogous to the search fields on the KOA search form.
Examples:
The following are sample parameter strings, which would be appended to the executable in the following manner:
https://koa.ipac.caltech.edu/cgi-bin/KOA/nph-KOA?parameter_string
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If no instruments are specified, all instruments are searched. Retrieve all data taken between October 5th and Ocober 7th, 2010 without performing calibration association: filetype=both&daterange=20101005-20101007 |
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If no modes are specified, then all modes are assumed. Retrieve all science observations for HIRES (all modes) taken between August 18th and 19th, 2004, without performing calibration association: instrument_hi=hires&filetype=science&daterange=20040818-20040819 |
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Retrieve all science observations for HIRES (all modes) and NIRSPEC (all modes) with "m13" in the TARGNAME keyword, and also any associated calibration files: instrument_hi=hires&instrument_ns=nirspec&filetype=science&calibassoc=assoc&spt_obj=objname&targname=m13 |
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Retrieve all science and calibration observations for NIRSPEC (high-dispersion mode only) taken on January 3, 2007 without performing calibration association: instrument_ns=nirspec&mode_ns2=high-dispersion&filetype=both&daterange=20070103 |
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Retrieve all science observations for NIRC2 (wide-imaging mode only) taken on May 17, 2009, and also any associated calibration files: instrument_n2=nirc2&mode_n23=wide-imaging&filetype=science&calibassoc=assoc&daterange=20090517 |
Instrument Parameters
If you don't want an all instrument search, you must specify at least one instrument. Additionally, if you don't want all modes for that instrument, you need to add relevant mode parameters for that instrument.
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DEIMOS: (no modes) instrument_de=deimos ESI: (no modes) instrument_es=esi HIRES: instrument_hi=hires HIRES modes: mode_hi1=iodine-in mode_hi2=iodine-out KCWI: (no modes) instrument_kc=kcwi LRIS: instrument_lr=lris LRIS modes: mode_lr1=blue mode_lr2=red mode_lr3=imaging mode_lr4=spectroscopy LWS: (no modes) instrument_lw=lws MOSFIRE: (no modes) instrument_mf=mosfire NIRC: (no modes) instrument_n1=nirc NIRC2: instrument_n2=nirc2 NIRC2 modes: mode_n21=narrow-imaging mode_n22=medium-imaging mode_n23=wide-imaging mode_n24=spectroscopy NIRSPEC: instrument_ns=nirspec NIRSPEC modes: mode_ns1=low-dispersion mode_ns2=high-dispersion mode_ns3=imaging OSIRIS: instrument_os=osiris OSIRIS modes: mode_os1=imaging mode_os2=spectroscopy |
File Type Parameters
You must specify a filetype as described below.
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Science files: To search for all science files matching the input parameters, set the file type as: filetype=science If filetype is set to science, there is an additional keyword/value pair that can be included to search for calibration files that are associated with the science files returned: calibassoc=assoc |
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Calibration files: To search for all calibration files matching the input parameters, set the file type as: filetype=calib By default, this will search for all types of calibration files. If you'd prefer to narrow your search to particular calibration types (done via checkboxes on the search page), you can include any of the following keyword/value pairs:
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Any files: To return all files matching the input parameters, both science and calibration (without running the calibration-association on the science files), use: filetype=both |
Search Criteria Parameters
Your GET query must include at least one of the following:
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Spatial Search: Set the spt_obj flag to "spatial": spt_obj=spatial Supply a coordinate string or object name to resolve, as well as a search radius and units (one of deg, arcmin, arcsec): locstr=location regSize=radius radunits=deg|arcmin|arcsec (arcsec is the default) Choose the resolver to attempt first, NED or SIMBAD: resolver=ned|simbad (ned is the default) |
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TARGNAME Keyword Search: Set the spt_obj flag to "objname": spt_obj=objname Provide a "target name" string: targname=object |
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UT Observation Date(s): Provide a date string: daterange=date_string Note that your date string must be properly URL-encoded. For instance, "08/19/2004" must be written as 08%2F19%2F2004. Simple date strings such as "20040819-20041101" do not require any special encoding. |
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UT Observation Time(s): Provide a time string: timerange=time_string Time strings must be URL-encoded if they include colons [:]; for instsance, "08:30" must be written as "08%3A30" |
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Exposure Time: To search by exposure time: exptime=exptime_string exptime_string can be a single value, a range, or an expression like "> 300". If special symbols are used, they must be URL-encoded:
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Program Information: To search by Program ID (progid), Semester, Program PI (progpi) or Program Title (progtitl): progid=progid_string semester=semester_string progpi=progpi_string progtitl=progtitl_string Note: if including any spaces or special characters, they must be URL-encoded. |
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Frame Number(s): The frame number search string can be complex, including several constraints separated by commas. Make sure to URL-encode any special characters and spaces: frameno=frameno_string |
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KOAID: To search by KOAID (filename): koaid=koaid_string |
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Wavelength Covered: (Available only for HIRES, LRIS, NIRC2, NIRSPEC, and OSIRIS) Provide a single wavelength value, or a range of wavelength values (WL1-WL2): wavelengthrange=wavelength_string wavelengthunits=angstroms|microns (angstroms is the default) |
URL-encoding special characters:
| Character | URL encoding |
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| Plus ("+") | %2B |
| Comma (",") | %2C |
| Forward slash ("/") | %2F |
| Colon (":") | %3A |
| Semi-colon (";") | %3B |
| Equals ("=") | %3D |
| Question mark ("?") | %3F |
| Space (" ") | %20 |
| Quotation marks (") | %22 |
| Less than ("<") | %3C |
| Greater than (">") | %3E |
| Percent ("%") | %25 |
Please acknowledge the use of KOA by including this text in your publications:
This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration.
Please also acknowledge the PI(s) of datasets that have been obtained through KOA, and please contact the KOA Help Desk if you publish archival data.
If your research uses data reduced by the DEIMOS DRP or MOSFIRE DRP, please use the PypeIt Citation.
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