Wavefront surfaces by Filter¶
Below are plots of the wavefront, or aberration, surfaces for out-of-focus images taken
with the g,r,i,z and Y filters. These plots are made from a single out-of-focus image, taken
at +1500 microns extra-focal. There are up to 1000 or so donuts identified and analyzed in each image.
The standard donut fit, to a Zernike expansion of the pupil-plane wavefront, is performed. Note
that the fit includes terms for focus (Z4), astigmatism (Z5,Z6), coma (Z7,Z8) and trefoil (Z9,Z10), but not spherical. Then the value of the Zernike term is plotted as a function of x and y position (in mm) on
the focal plane. The units for the plots are waves, at 700nm, for all terms except focus, which
has been converted to microns of defocus.
Note that the plots for r,i,z and Y look quite similar, but the aberration surfaces for g band are notably
different, particularly in Coma and to a lesser extent in Astigmatism. This difference may be expect - more
study with the Zemax optical model is needed.
The plots have titles with the Zernike z4 through z10 and then the image number
155288 is g band
155289 is r
155290 is i
155291 is z
155334 is Y
(sorry no u band image)