Seeing and sky brightness

Seeing and sky brightness affect both the completeness of the SDSS and the accuracy of its star/galaxy separation. Seeing is defined here as the effective width of the point spread function (see section 4.3 of the EDR paper). The following plots show the fraction of DR1 fields exceeding a given seeing and sky brightness.

Seeing	Sky brightness

These are the r-band quartiles:

Parameter	Lower quartile	Median	Upper quartile
PSF width	1.58"	1.43"	1.30"
Sky brightness	20.70 mag	20.86 mag	21.03 mag

Last modified: Tue Feb 17 18:41:43 CST 2004