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Obs Status DB - will aggregate GBT and VLA schedule data for query by API process. Will be hosted on VLA database server. Growth is not anticipated to be that large even over a few years. Schema needs finalization, but proposed columns are:
- site - GBT or VLA
- effective datetime UTC - used to determine effective schedule when previous schedule has been updated.
- obs start datetime UTC
- obs end datetime UTC
- RA of source
- Dec of source
- tracking rate of instrument
- frequency range of observation (in Hz or MHz)
- text field (for notes)
API process - will expose REST interface to SpaceX. API process will receive request from SpaceX, query Obs Status DB for GBT and VLA observation status data and format and send response to SpaceX. API format to be finalized. Interface security needs to be finalized. API process will be deployed on a VLA web server.
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- Even if VLA Operations agree to set targets 20 minutes in advance, there is no guarantee that observations will end on time (for example, due to a sudden change in weather conditions or hardware failure).
- Manual observation scripts can be read, but may not meet the 20-minute advance notice.
- The VLA executes multi-band observations. For example, Super Novae explosions can be characterized by all VLA bands, with just a few minutes of separation between each band. The "frequency range of observation" needs to be compatible with what the API consumer are expecting.
- The VLA data sender needs to be per scan instead of per SB. Flux and polarization calibrators are usually far from Science target field, and some SBs have Science Targets in different fields.
- For the VLA, the initial 10 minutes of observation are critical. It is when the Observers are instructed to set the Attenuation gains. If the flux of a satellite changes the this setting, all the Observation block can be compromised (TBD).
- The array configuration is not relevant (TBD).
GBT Notes
- We anticipate pulling data from the DSS, which should give us the scheduled observations sufficient for the 20 minute window. However, this may not account for projects that are not Open Skies, such as BTL.
- We'll be reporting scheduled targets with the understanding that observers are technically free to do whatever they want in their sessions i.e. there's no enforcement that they have to abide by what's in their proposal.
- We're also deliberately ignoring pointing to calibration sources, raster mapping, daisy scans, etc. with the assumption that these should all be close to the source and/or aren't in scope for a "hello world" demo.