User Access and Proprietary Periods

Proprietary Periods

An observation's proprietary period is the length of time between the original observation and the date when it becomes available to the public. The default proprietary period for all KOA data is eighteen (18) months; however, the KOA Data Release Policy gives principal investigators the option to request different proprietary periods on a per-program, per-night, and per-CCD basis.

User Types

KOA Users access data in two different ways:

  • Principal Investigators (PIs):
    Only PIs can access data during its proprietary period - you must have a user account that has specifically been granted proprietary access to that data set in order to access it before it has become public.
  • General Users:
    Anyone may search for and download data which has passed its proprietary period. No account is necessary to access public data.

Your user type affects search results:

  • If all CCDs associated with an observation are proprietary, only the PI will be able to view information about the observation.
  • Once at least one CCD in an observation has passed its proprietary period, all users (both PIs and general users) will be able to retrieve descriptive information about the observation. The number of CCDs available to the current user is displayed as a column in the search results page.
  • Calibration files taken for a given night and observing program will be publicly available as soon as any part of any science files for that night become non-proprietary.

FITS file contents for a given observation depend on user type:

  • If no data are public... PIs are always able to download complete, unaltered FITS files from their own observing program(s). General users, including PIs for other observing programs, will not be able to retrieve any proprietary data.
  • If all data are public... All users can download complete, unaltered FITS files that have no proprietary CCDs remaining.
  • If some data are public... If some, but not all, CCDs in an observation are still proprietary, and you are not logged in as the PI for that particular observing program, any part of a multi-extension file will have the proprietary period blanked out. I.e., any HDU image blocks with data from proprietary CCDs will have all their pixels set to the value of the BLANK header keyword. A COMMENT keyword will be added to the HDU header indicating that the data are still proprietary. The primary FITS header will be left intact, as will all header and data blocks corresponding to non-proprietary CCDs.
  • Note: Calibration files are never altered; the proprietary period for each calibration CCD is the same as the shortest proprietary period for science files taken that night.

Logging In

To access proprietary data, users must go to the Login Page and enter a userid and password.

Links to log in/out of the archive, or to change your password, are available from the main KOA Search Form.


  • You must have cookies enabled in your browser to log into the Keck Observatory Archive.
  • After logging in the first time, you will not be asked to enter your password again as long as your browser stores the KOA cookie. If you access KOA from another browser or machine, you will need to log in again.
  • The account you log in with does not affect the email address which receives notification when your files are ready. Each account is affiliated with an email address (the one to which WMKO sends the original account information); however, you must enter a notification address every time you select data for download packaging.

Obtaining a PI Account

At the start of a new observing program, a user account is automatically created for the program's principal investigator (PI). This account is allowed to access proprietary data taken as part of the PI's program (as well as any non-proprietary data available in the archive). If the PI has already observed with a KOA instrument in a previous semester or under a different program ID, their account will be updated to allow proprietary access to their new data.

Each new PI will receive an e-mail from WMKO with their account username and password. To change your password, click on the "Change Password" link on the bottom of the Login Page.

A PI can grant access to their program by another user by submitting a request to the KOA Helpdesk.