Changes between Version 2 and Version 3 of dbSchemaUpdateApr09


Ignore:
Timestamp:
04/09/2009 06:13:02 AM (11 years ago)
Author:
jbecla
Comment:

added definitions for moments

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  • dbSchemaUpdateApr09

    v2 v3  
    7171 
    7272-- First and second moments. These are per model per filter, all FLOATs 
    73 uIxPS, uIyPS, uIxxPS, uIyyPS 
    74 uIxSG, uIySG, uIxxSG, uIyySG 
    75 }}} 
    76  
     73uIxPS, uIyPS, uIxyPS, uIxxPS, uIyyPS 
     74uIxSG, uIySG, uIxySG, uIxxSG, uIyySG 
     75}}} 
    7776 
    7877Notice that we are proposing to use “dec” instead of “decl”. “Dec” is strongly preferred by astronomers. We will always have model type attached to the “dec/decl”, so the issue with “dec” being a reserved word in some RDBMSes goes away. 
     78 
     79The moments are defined as: 
     80 * Ix = integral_over_footprint[w(x-x0,y-y0)*f(x,y)*(x-x0)] 
     81 * Iy= integral_over_footprint[w(x-x0,y-y0)*f(x,y)*(y-y0)] 
     82 * Ixy = integral_over_footprint[w(x-x0,y-y0)*f(x,y)*(x-x0)*(y-y0)] 
     83 * Ixx= integral_over_footprint[w(x-x0,y-y0)*f(x,y)*(x-x0)*(x-x0)] 
     84 * Iyy = integral_over_footprint[w(x-x0,y-y0)*f(x,y)*(y-y0)*(y-y0)] 
     85 
     86Where: 
     87 * x0,y0 is the object center 
     88 * w(x,y) is a weighting function 
     89 * f(x,y) is the flux  
    7990 
    8091