MegaCam to SDSS system (to 2005Jul20)

All data up to 2005 July 20 (at which point there was a problem in the processing says J-C June 7, 2006).

Pairs of stars, same night (Theil/lsq)
Pairs of stars, same exposure (Theil/lsq)
Single stars, Q-run corrected (Theil/lsq)

Pairs of stars, same night (Theil/lsq)

Stars observed on the same night (though not necessarily the same exposure). For each pair of stars, I plot the zeropoint difference against the colour difference. This technique takes out night to night extinction and zeropoint drifts. The observations are extinction corrected, but (obviously) not colour term corrected. The two numbers given in the table are for a Theil slope and least squares slope (with iterative outlier rejection).


g'


r'


i'


z'

Pairs of stars, same exposure (Theil/lsq)

Stars observed on the same night and also the same exposure . For each pair of stars, I plot the zeropoint difference against the colour difference. This technique takes out night to night extinction and zeropoint drifts, and even transparency changes in the night. The observations are extinction corrected, but (obviously) not colour term corrected. The two numbers given in the table are for a Theil slope and least squares slope (with iterative outlier rejection).


g'


r'


i'


z'

Single stars, Q-run corrected (Theil/lsq)

Single stars: colour vs. zeropoint. An offset is applied for each queue run to align the different queue runs. The observations are extinction corrected, but (obviously) not colour term corrected. The two numbers given in the table are for a Theil slope and least squares slope (with iterative outlier rejection).


g'


r'


i'


z'