jchate6
commented
1 day ago For reference: GST = "Greenwich Sidereal Time" This is the current Sidereal Time at the Prime Meridian (also used to determine UTC) as opposed to: LST = "Local Sidereal Time" The Current Sidereal Time at the local Meridian.
Sidereal Time = The Hour angle of the equinox. This is the equivalent of the RA passing directly over head at the reference location. This is a standard and useful unit of measurement since it lets Astronomers easily reference what is currently visible from a given location. Effectively a sidereal day is how long it takes the earth to rotate with respect to the stars, and a standard (solar) day is how long it takes to rotate with respect to the Sun. This makes a sidereal day ~4min shorter than a solar day because the Earth has moved in it's orbit over the course of that day and needs to rotate just a little bit further to point the same meridian back to the sun.
There are astropy methods for figuring this out. And it should not be difficult to incorporate such a field in a facility.
Discussions with the Opticon/Radionet Pilot group raised the question of submitting a single observation request to a network of facilities either through a single call to a single portal or through multiple portals. Due to the way the scheduling system for radio facilities calculates GST, the discussion concluded that the observational request should include a user's requested date range which each facility can then interpret and schedule the observations at a suitable GST interval.
Action for the TOM team is to evaluate whether this is a viable modification to our observation request schema.