Authenticated Access (Login)#

Most datasets in the ESO Science Archive are publicly available and can be downloaded anonymously without requiring authentication. However, access to proprietary datasets—such as those under active proprietary periods—is restricted to authorised users (e.g., PIs of observing programmes and their designated delegates). These users must authenticate via the ESO User Portal.

Authentication is handled using the login() method. This command initiates a secure login session via the ESO Single Sign-On (SSO) service. It integrates with the keyring module to securely store your password in your system’s credential manager. After the first login, you should not need to re-enter your credentials for subsequent sessions on the same machine.

Authentication is required when:

  • Downloading proprietary files (not yet public)

  • Accessing services that require ESO user privileges

Login Examples#

The following examples show typical login and data retrieval workflows:

First example: "TEST" is not a valid username, it will fail:

>>> from astroquery.eso import Eso
>>> eso = Eso()

>>> eso.login(username="TEST")
WARNING: No password was found in the keychain for the provided username. [astroquery.query]
TEST, enter your password:

INFO: Authenticating TEST on ‘www.eso.org’ … [astroquery.eso.core] ERROR: Authentication failed! [astroquery.eso.core]

Second example: pretend "ICONDOR" is a valid username:

>>> eso.login(username="ICONDOR", store_password=True)
WARNING: No password was found in the keychain for the provided username. [astroquery.query]
ICONDOR, enter your password:

INFO: Authenticating ICONDOR on ‘www.eso.org’ … [astroquery.eso.core] INFO: Authentication successful! [astroquery.eso.core]

After the first login, your password has been stored:

>>> eso.login(username="ICONDOR")
INFO: Authenticating ICONDOR on 'www.eso.org' ... [astroquery.eso.core]
INFO: Authentication successful! [astroquery.eso.core]

Successful download of a public file (with or without login):

>>> eso.retrieve_data("ADP.2023-03-02T01:01:24.355")
INFO: Downloading datasets ... [astroquery.eso.core]
INFO: Downloading 1 files ... [astroquery.eso.core]
INFO: Downloading file 1/1 https://dataportal.eso.org/dataPortal/file/ADP.2023-03-02T01:01:24.355 to ... [astroquery.eso.core]
INFO: Successfully downloaded dataset ADP.2023-03-02T01:01:24.355 to ../ADP.2023-03-02T01:01:24.355.fits [astroquery.eso.core]
INFO: Done! [astroquery.eso.core]

Access denied to a restricted-access file (as anonymous user or as authenticated but not authorised user):

>>> eso.retrieve_data("FORS2.2010-10-23T23:38:41.912")
INFO: Downloading datasets ... [astroquery.eso.core]
INFO: Downloading 1 files ... [astroquery.eso.core]
INFO: Downloading file 1/1 https://dataportal.eso.org/dataPortal/file/FORS2.2010-10-23T23:38:41.912 to ... [astroquery.eso.core]
ERROR: Access denied to https://dataportal.eso.org/dataPortal/file/FORS2.2010-10-23T23:38:41.912 [astroquery.eso.core]
INFO: Done! [astroquery.eso.core]

Password Storage#

As shown above, your password can be stored securely using the keyring module by passing the argument store_password=True to Eso.login(). For security reasons, password storage is disabled by default.

Warning

MAKE SURE YOU TRUST THE MACHINE WHERE YOU USE THIS FUNCTIONALITY!!!

When using the store_password=True option, your password is stored in your system’s keyring. This provides secure local storage, but only do this on machines you fully trust.

Note: You can delete your stored password at any time using keyring.delete_password. In this example, the call is wrapped in a helper that checks for the credential’s existence before attempting deletion:

>>> import keyring
>>> def safe_delete_password(service, username):
>>>     if keyring.get_password(service, username) is not None:
>>>         keyring.delete_password(service, username)
>>> safe_delete_password("astroquery:www.eso.org", "your_username")

Automatic Login#

To avoid having to enter your username every session, you can configure a default username in the Astroquery configuration file. This file is located as described in the astropy.config documentation.

Add the following to the [eso] section of your config astroquery.cfg file:

[eso]
username = ICONDOR

Once set, you can simply call eso.login() without specifying a username:

>>> eso.login()
ICONDOR, enter your ESO password:

Note: If automatic login is configured and the password is stored, other Eso methods (e.g. retrieve_data()) can log you in automatically when needed.