... Archives . ... I couldn?t believe my eyes when I saw 4754 degrees of freedom (d.f.) and chi-square test statistic 4859. I?ve often enough seen large degrees of freedom from journals in astronomy, several hundreds to a few thousands, but I never felt comfortable at these big numbers. ... The point is that either simple or complex, at the end, if someone has a data file with large number of photons, n is generally larger than observations with sparse photons. ... Chandra Blog . ...