ObsLocTAP support for TOMToolkit

[phycodurus]

Let's support @talister and FOMO's use case.

[jchate6]

@talister what is your use case and how can we support you?
Please link the Jupyter notebook and any branches or code we can use for reference.

[talister]

@talister what is your use case and how can we support you? Please link the Jupyter notebook and any branches or code we can use for reference.

Sure. My use case was motivated by the AstroNote that said that starting July 5 ZTF would be shadowing the Rubin Science Verification (SV) footprint. ZTF announce their planned/scheduling pointings through the Schedule Reporting Service via ObsLocTAP, which will also be used by Rubin.
So I figured that having a "where will ZTF be pointing?" as a ObsLocTAP use case would be of:

1. of interest to various TOMs now to see what follow-up might be obtained on your targets for "free",
2. a good precursor for the Rubin future,
3. with the AladinLite widget already in tom_toolkit and TreasureMap expertise would be easy to implement,
4. (Plus I learned from Joseph's public talk there is going to be the Blanco+DECam SHADOW as well which would be similar).

At present I have a notebook which fetches the scheduled ZTF fields for a given night and plots the patches, along with the Rubin SV footprint as a demo.
I think what I would want would be a general way for TOMs to fetch and visualize this sort of "where will survey X look in the future?" so this probably would want:

• A generic ObsLocTAP handler and a concrete implementation for the ZTF Reporting Service for now (with a Rubin implementation to follow)
• A way to have the TOM refresh these scheduled/observed fields on a suitable cadence that makes sense (nightly?)
• Maybe a way to persist these fields to reduce runtime/load on the external service?
• Some way of associating a per-instrument footprint, either simplifying circle/boxes or the correct detector layout, with each of the pointings (think TreasureMap has this already?)
• A way to plot and visualize these pointings on the sky, along with the TOM's Targets

Let me know if more info is needed

[talister]

Note: this should be ObsLocTAP in the title since its TAP for Obs(erving)Loc(ations)...