Access to forced photometry and postage stamps defined by sky position (not DIAForcedSource position)


(Stephen Smartt) #1

Final couple of questions for now, on broker related data access :

Section 3.3.4 in LSE-163 : notes that a “precovery service” will be available for a limited number of DIAForcedSources across ALL previous visits, and returns results within 24hrs of request. But can this be for any arbitrary sky position ? Or must it be a the position of either an existing DIASource or DIAObject?

All image data (raw, processed, difference) are available to download no later than 24 hrs from end of visit acquisition. But will there be a “postage stamp” type service based on the “precovery service”. e.g. can a broker send a request for n forced photometry measurements, and also request the triplet of images (target, reference, difference) for stamps of arbitrary size (within reason !) ?


(Melissa Graham) #2

Hi Stephen, I have some answers from the DM team for you.

Yes, the precovery service can be used to generate DIAForcedSources for any arbitrary sky position. Also yes, it will be possible to generate image triplets (cutouts) from direct, reference, and difference images for any given location, from the Prompt and/or Data Release images. For example, any user of the LSST Science Platform (including brokers) could generate and retrieve these cutouts of a desired size through the API aspect. However, it is important to note that such user-generated photometry and image cutouts would be proprietary.

I hope that clarifies things and, as always, am happy to answer any follow-up questions!
Melissa


(Stephen Smartt) #3

thanks @MelissaGraham ! very helpful.