How to Check KOA Data for Replication


NASA proposers to Keck are asked to verify that the science goals for which they are requesting Keck time cannot be achieved with public data in KOA.

This document is designed to help new KOA users and NASA Keck proposers determine if their objects of interest have public data in KOA and to present the methods for gathering information about the observations. In the case of overlapping targets, the best way to determine if the existing data are sufficient to meet your scientific goals is to download and examine them.

MOSFIRE slit masks can be examined by reading the FITS headers. Please note that LRIS slit masks are unavailable in KOA.

You may learn more about available data reduction pipelines here.

Using the KOA Search Interface:

If you have a single target:

  • Go to the KOA Basic Search at: (link opens in new window)
  • Follow these instructions:
    • Leave checked only the instruments you are interested in.
    • Select 'Object Name or Location' and enter your coordinates or name resolveable by SIMBAD or NED.
    • Adjust the search radius if desired.
  • Click on the 'Search' button at the bottom of the page


If you have multiple targets:

You may prepare a list of targets in a file and upload it to KOA, which returns a summary of all data available for all selected instruments. The format of the uploaded file may be CSV, tab-delimited, or IPAC ASCII. See Table Formatting for detailed information and examples.

The simplest approach is, however, to simply prepare tables of object names or a list of positions, per the two samples below. The tables must be saved as ASCII files: use editors that do not add special or hidden characters.

Table Option 1: List of objects resolvable by NED/SIMBAD.

Each line in this table should be a resolvable object. No header is necessary.

Sample table:

  ngc 1097

Table Option 2: Table of locations

The header of this table must include 'ra' and 'dec'. You may optionally include an 'object' column; if it is populated, its contents will be used to label each row of the search results.

RA and Dec must be J2000 coordinates and may be given in decimal degrees or sexagesimal.

Sample table:

289.147941100,30.184500500, M56
277.158208330,-66.982277780, ic4710
179.874583330,-19.297222220, object 3

How to upload your table:

  • From the main KOA site, click on the 'More Search Options' tab (or click here to open it in a new window).
  • In section 1, leave selected only the instruments you are interested in.
  • In section 2, select 'Return only science files' and make sure that the 'Also show calibration files...' checkbox below is selected.
  • In section 3, change the search radius as needed.
  • In section 3, choose Multiple Object Table File and upload your table of object names or locations.
  • Click on the 'Search' button at the bottom of the page

The results page from a Multi-Object search will show which objects have public data.

Sample Multiple Object Table File Results:

Click on the 'See Results' link to examine the observations.


Understanding Search Results:

From the results page, you can (if desired):

  • Filter and sort the results to explore the data attributes such as exposure time, seeing (when available), and instrument configuration keywords. Note that for some instruments, information about the configuration is only available in the FITS header.
  • Click on the links in the 'Quicklook Previews' column to browse the FITS header, JPEG preview, and the raw and/or reduced data (FITS browsing capabilities vary by instrument)
  • Package desired data for download and investigate using your own tools.
  • Verify that sufficient calibration files exist to reduce the data.


Accessing Weather Data:

  • From the 'More Search Options' page, or from a results page, scroll to the bottom for the 'Retrieve ancillary weather data' search box.
  • Enter a single date or range of contiguous dates (ie: 08/24/2004-08/28/2004), and click the 'Go' button
  • For more information on what ancillary weather data are available, see our User Guide

Download Tables of All Public Observations

KOA provides ASCII tables, updated weekly, which contain records of all public science and calibration data for each instrument.

These tables may be useful for observers with much longer target lists who prefer to perform filtering/searching using their own tools or scripts.

Column descriptions are unique to each instrument, and summarized in the documentation links included.

Last Updated: Feb 01 2023
Instrument CSV (size) IPAC ASCII (size) # Observations Column Descriptions
DEIMOS [CSV] 63.4 MB [IPAC] 170.3 MB 186,731 Column Descriptions
ESI [CSV] 25.3 MB [IPAC] 70.6 MB 75,435 Column Descriptions
HIRES [CSV] 160.0 MB [IPAC] 547.8 MB 450,483 Column Descriptions
KCWI [CSV] 13.6 MB [IPAC] 41.1 MB 35,484 Column Descriptions
LRIS [CSV] 224.5 MB [IPAC] 689.6 MB 580,800 Column Descriptions
LWS [CSV] 7.1 MB [IPAC] 20.6 MB 23,737 Column Descriptions
MOSFIRE [CSV] 137.3 MB [IPAC] 345.4 MB 333,784 Column Descriptions
NIRC [CSV] 79.1 MB [IPAC] 226.2 MB 260,117 Column Descriptions
NIRC2 [CSV] 441.3 MB [IPAC] 1.3 GB 1,064,925 Column Descriptions
NIRES [CSV] 21.5 MB [IPAC] 59.9 MB 61,954 Column Descriptions
NIRSPEC [CSV] 437.2 MB [IPAC] 1.2 GB 1,122,817 Column Descriptions
OSIRIS [CSV] 101.3 MB [IPAC] 326.1 MB 278,711 Column Descriptions