USNO vs 2MASS sigma distribution.
Sigma = sqrt( usno_sigma**2 + 2mass_sigma**2 ) vs abs(latitude).
Overall Sigma vs Distance of USNO and 2MASS solutions.
2MASS sigma distribution vs y=abs(galactic_latitude)
USNO sigma distribution vs y=abs(galactic_latitude)
2MASS sigma distribution as function of abs(declination).
USNO sigma distribution as function of abs(declination).
2MASs sigma distribution as function galactic longitude.
USNO sigma distribution as function of galactic longitude.
USNO sigma, function of max shift of association members (80,000 := 80 pixels)
USNO distribution of the number of sources found (y) vs the number of sources used (x)
USNO distribution of the sigma (y) vs the number of sources used (x)
2MASS distribution of the number of sources found (y) vs the number of sources used (x)
2MASS distribution of the sigma (y) vs the number of sources used (x)