How much of the DM stack is available today to get to a catalog?

[drphilmarshall]

Do we know what steps we would execute?

Questions from Richard, pre-hangout.

Having a sense of which basic measurements are possible right now is a good idea. Maybe @SimonKrughoff can summarize, or point us to a good DM README?

[drphilmarshall]

Robert Lupton told me earlier that the current activity on the DM stack is in merging the HSC release into LSST master - and that while this will not include MultiFit, it will include forced photometry. Which means we should be able to start trying to extract lightcurves sooner rather than later!

[wmwv]

Things currently easily available in the DM stack include:
Source detection
Measurements of sources: PSF flux, elliptical aperture flux, centroids, basic shape information

[wmwv]

I have tested out basic image subtraction and it seems to work fine. It can be a bit sensitive to the quality of the input star catalog and may need some parameter tweaking for the allowed Alard-Lupton spatial variation, but this should be straightforward.

[drphilmarshall]

Great! That makes the diffsource catalog pretty interesting. Is forced
photometry available yet?

On Tue, Feb 17, 2015 at 8:52 PM, wmwv notifications@github.com wrote:

I have tested out basic image subtraction and it seems to work fine. It
can be a bit sensitive to the quality of the input star catalog and may
need some parameter tweaking for the allowed Alard-Lupton spatial
variation, but this should be straightforward.

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#14 (comment)
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[djbard]

Yes, forced photometry is available - it's described in the SDSS example here and a pipe_task here but it doesn't seem to be as well documented as some of the other tasks.

[drphilmarshall]

We know a lot more about this now - see notes in #54