== Color Color diagrams from SAS 39 data ==

Ken suggested that I look at the full force mean psf magnitude measurments by making color color diagrams. I thought it might be useful to compare these to the stack photometry so I did plots from those data as well.


== Forced Photometry ==

IPP psps forced photometry takes the positions of the detections made in the stack photometry and does forced photometry on the single frame warp images. 

I decided to use the "view" !ForcedMeanObjectView which is a join of the tables ObjectThin and ForcedMeanObject. I decided to cut on the qualityFlag requiring that the "good stack" bit be set. In order to keep they query time
managable I queried a subset of the survey using the projectionID column. This restricted the results to objects in projection cell 1406 (334 < ra < 338 0 < dec < 4)

The query was
{{{
select ForcedMeanObjectView.*, (ForcedMeanObjectView.qualityFlag & 1) as extended   
INTO mydb.[forced_1406] from ForcedMeanObjectView 
where projectionID = 1406 and (ForcedMeanObjectView.qualityFlag) & 16 = 16
}}}
This yielded 562,311 objects.

The ForcedMeanObjectView only has fluxes.  Since this was my first set of queries in awhile I decided not to convert the fluxes to magnitudes in the query. I simply grabbed the objects and ran the results through
various iterations of a [http://www.star.bristol.ac.uk/~mbt/stilts/ STILTS] program to convert to magnitudes.at I used.