BCAM IQ plots with airmass cut¶
The data set for these plots are from the IQ catalogs from January to May, demanding that r50 be defined. This effectively selects only images after mid-February. Additionally, we select only exposures for which airmass < 1.1, since this is the largest variable affecting the image PSF. This selects exposures which were taken within roughly 25 degrees of zenith.
Here is the r50 distribution for these data:
Similar to the plots without the airmass cut, we show two plots of PSF vs. pointing to ensure that any BCAM / image quality correlations are not dominated by good PSF at a particular pointing. Here is the distribution of (HA, Dec) in each PSF bin:
And here is a scatter plot of the same data:
Finally, here are the image quality profile histograms of BCAM mis-alignments versus r50:
The "best fit" relationship between BCAM and PSF is different than the one found without the airmass cut. This is not surprising, since a larger range of telescope pointings will introduce a larger range of BCAM-inferred mis-alignments. The important things is that the intercept--the BCAM readings associated with the best image quality--are the same.
Here is a similar plot with the axes swapped: