Monitor Database

One of the functionalities of the Opihi telescope is to record and monitor the atmospheric conditions over time. This functionality is similar to the CFHT SkyProbe.

In both Manual Mode or Automatic Mode, OpihiExarata can save zero point data obtained from solving the photometric solution of an image. (See Compute Photometric Solution for computing the photometric solution in manual mode, and Automatic Mode generally for computing the photometric solution in automatic mode.) We save the zero point information in a database.

Database Schema

The layout of a database is typically described by the database schema. For our purposes, we find that a flat file database is the simplest to understand for those unfamiliar with OpihiExarata itself. Although typically a general user will interact with this database through the output of the monitoring webpage (see Zero Point Monitoring), there may be the case where the full data is needed.

The database is a flat text file database following the following hierarchy:

  1. All database files are stored in a single directory. To mark that it is an OpihiExarata database directory, a blank file exarata_zero_point_database.check exists. This file is made upon a new database directory and is required.

  2. Each file of the database represents a single day of data. The filenames are given as YYYY-MM-DD.txt where the date is the UTC date of a given zero point observations.

  3. Each line within a given file of the database is a single zero point observation. The UTC time and date (in ISO 8601 format) is provided along with the zero point value, error, and name of the filter per Filter Names.

Managing the Database

The database is custom to this software and so the API which manages it is also native to OpihiExarata. The database is managed with an instance of the database solution class found. (For more information, see OpihiZeroPointDatabaseSolution.)

As records are appended to the files of the database, some records may get out of order. The API interface provides methods to clean up the database.

The location and other interactions between the database and the other parts of the OpihiExarata software is configurable via the configuration file, see Standard Configuration File.