Accessing environmental data via API calls

The table below shows some commonly used atmospheric data needed to support the safety of the operations or the scheduling of scientific observing blocks. These fields consist of 1-minute averages, except for the barometric pressure field that, which is the instantanous value.

Besides these data fields, there are other data in the ASM database and also other metrics, such as the maximum, the mimimun, or rms values of variables in periods of 1 minute or 20 minutes.

Examples of how to access the ASM data with an URL call:

1. Query the ASM database to extract the seeing data since date 2024-07-29 at 00:00:00 UT.

https://www.eso.org/asm/api/?from=2024-07-29T00:00:00Z&fields=dimm_paranal-fwhm

2. Query the ASM database to extract the seeing data from date 2024-07-29 at 09:00:00 UT to 2024-07-29T10:00:00 (i.e. an specfic period of time).

https://www.eso.org/asm/api/?from=2024-07-29T09:00:00Z&to=2024-07-29T10:00:00Z&fields=dimm_paranal-fwhm

The data output is a JSON data structure (Fig. 1). For the second example the data output includes the time of the measurement (in Unix time in milliseconds) followed by the seeing data (physical units in arcsecs).

^{Fig. 1 Example of a JSON data structure}

The URL query can be programmed in a python code where the dates for the from and to fields are set dynamically in the code. For instance:

url_= "https://www.eso.org/asm/api/?from=%sZ&to=%sZ&fields= dimm_paranal-fwhm " % (date_fr, date_to)

where date_fr, and date_to are set in the code following the same format shown in the examples above.

^{Table 1 Weather intruments variable names}