Bad seeing and bad ellipticity data distribution on the sky¶
Implications for observers¶
The take away from these is that we should avoid Dec=0, Ha=0 in particular.
Tim says that there may be a subtle cable wrap problem; until we hear otherwise
observers should use the ObsTac select tactician via configuration file method
to keep from observing the MiniSurvey at HA = 0.
The data plots¶
Plots of HA, Dec and bad ellipticity:
These are plots of the observation centers in HA and Dec.
The first uses good science data from Dec 2 and 3 plotted in blue.
The red points are all e > 0.15 data (from QR) from Dec 2 on.
The second plot uses all on-sky data from Dec 2 through Dec 7, then plots all
the e > 0.15 data on it.
The latter gives a better sense of the frequency of the occurrence of the
e > 0.15, but has distractions like short standard star observations.
Wait, what is the difference between the two plots?
The first plot has Dec 2 and Dec 3 data (desdays -17 and -16) in blue,
and only includes SN and main survey data.
The second plot has all data taken between Dec 2 and Dec 7 that has
e > 0 and fwhm > 0; this should reject flat fields, bias images, but not
The red dots in both plots are the same; they are all data between Dec 2 and Dec 7
that has e > 0.15.
These are histograms of e > 0.15 data in HA and in declination.