GBT Data Sender

Background

Observations on the GBT are scheduled using the Dynamic Scheduling System (DSS). The GBT Data Sender queries this system for details about upcoming observations, and sends that data to the OSSDB via the REST API.

Note that while the DSS contains scheduled observations, observers are not constrained to following those stated intentions.

The DSS Database

To learn more about the DSS, please see the following resources:

• http://docs.greenbankobservatory.org/repos/nell/docs/sphinx/source/deployment_overview.html
• https://safe.nrao.edu/wiki/bin/view/GB/Software/DssDocs

The OSS Exporter

The exporter consists of a Django command in the nell app, which pulls values from the DSS database and pushed them to the OSS database. The read and write URLs for the database are stored in a configuration file with restricted permissions.

DSS Information

For a given looktime defined as now + 30 minutes, we first identify the observing period (look_period) and receiver (period_rx) which correspond to that time. 

look_period = Period.objects.filter(start__gte=self.looktime).order_by("start").first()

period_rx = Period_Receiver.objects.filter(period=self.look_period.id).first()

Site Data

The following information is sent as a JSON object to be a site_data entry in the OSS database.