Known asteroid photometry and lightcurve from public alerts

[mcoughlin]

Feature Summary
Would it be possible to use Fritz to show the photometry as a function of time for all known asteroidal sources taken from the alert stream? Showing the photometry as a function of time would enable monitoring of asteroid brightness and detection of sudden brightening events such as those cause by disruptions.

Implementation
From @dmitryduev :
To allow filtering on that in Fritz, a new kind of a filter needs to be implemented:

• Add a flag/field to K filter definition {solar_system: <true|false>}, propagate this to the SP filtering extension
• Define dedicated upstream stages for filters with {solar_system: true} (see https://docs.fritz.science/user_guide.html#upstream-aggregation-pipeline-stages) that would:
  • check if candidate.ssnamenr is not null and candidate.distssnr is < 2 or something similar.
  • pull alerts by candidate.ssnamenr (and not prv_candidates as for transient filters)
  • fit a polynomial to the magpsf time series and report the "predicted" value?
• The id to use when posting to SP should be candidate.ssnamenr and not objectId as for transients.

Alternative Implementation
Perhaps a faster way to achieve the same thing as discussed above would be to implement a custom sentinel service, somewhat similar to the one I wrote for Tails.
That service would:

• periodically query Kowalski for the latest batches of alerts with candidate.ssnamenr that is not null and candidate.distssnr that is < 2 or something
  • for the newly identified detections, pull alerts from corresponding asteroids by candidate.ssnamenr
• fit a curve to the time series, or do whatever complicated thing you want, extrapolate that to the time of observation and compare that to the actual detection
• if it exceeds a threshold of some kind, post results to Fritz.

From Ashish:
The time series/polynomial fitting will be more involved due to rotations, relative positions of the asteroid, the sun, and Earth. What I was hoping to do is to first get a sense of these variations for a large number of named/known asteroids within ZTF data to be able to define some kind of threshold (as you say in your comment above) which can then be used as a sentinel service. Right now I don't know even the number of observations available within ZTF for various asteroids.

Copied from fritz-marshal/fritz-beta-feedback#37