Details
-
Type:
Story
-
Status: To Do
-
Resolution: Unresolved
-
Fix Version/s: None
-
Component/s: Design Documents
-
Labels:
-
Team:DM Science
Description
Right now, the DPDD does not say that we will save Sources from science images during alert production; we only save DIASources and DIAObjects, so there the direct-image results are not guaranteed to be in a database until DRP.
I'm opening this ticket to track potential use cases where Sources are important in AP, or potentially to track any reasons not to save Sources.
Attachments
Activity
Repeating a point from the SST meeting today: this question is also tightly bound with the "what payload are we actually running on new data in LOY1?" question. For sky regions where we don't have templates yet, will there be any catalog data products at all, then, or just calibrated images (that we only keep around for 30 days before dropping them and leaving only lossy-compressed versions)? It's clear that there would be even more demand for Source-like data in some of these cases?
Some of this was already discussed in DMTN-107, Options for Alert Production in LSST Operations Year 1.
This was raised at the 2021 PCW today, so I wanted to chime in that for some science cases (e.g., searching for Solar System objects where there are no templates) even severely paired down source catalogs (just ra, dec, psfMag) would be extremely useful (and even if delivered as a series of FITS files). More generally, if the volume of the data is an issue, I suspect a subset of columns may satisfy a number of user cases discussed here.
I'll add this to a DM-SST meeting in September to discuss
Just in case I miss DM-SST meeting - it seems to me that it would be very useful for variety of reasons to have Source catalogs for the last k months (k~1) available in some form. As for the data volume, we can pair down the columns as Mario already said, and also play rounding tricks, similar to those that were used with early versions of the SDSS quasar catalog (e.g., don't store mag=12.3456789 but rather 12.35 or 12.346).
That's a fair point on the data volume; I had not looked up the numbers myself. I could imagine another minimal solution would be to store ~14 or 30 days of Sources. (One could reasonably argue that if you really need Sources from 6 months ago, you should just wait for the DR.) There might also be diagnostic merit in having that data, at least in the early stages of the survey.