Colloquium
Here is the schedule for Fall 2025
Previous abstracts of colloquia from this semester will be archived as the semester progresses.
This week's seminar will be held at the usual 4 pm time in Workman 101.
Speaker: Dr. Jaren Ashcraft
Affiliation: NASA Hubble Fellow at UC Santa Barbara
Polarization in Astronomical Telescopes: Efforts in controlling polarization in NASA's
Habitable Worlds Observatory. (Optical engineering career pathways)
NASA’s Habitable Worlds Observatory (HWO) aims to achieve contrasts of one part in
10 billion to detect and characterize exo-Earths. This ambitious goal requires an
instrument so sensitive that we must contend with error terms that have not limited
previous high-contrast instrumentation. Polarization is one such source of error that
is particularly problematic for coronagraphy onboard a large space telescope. In large,
compact, astronomical observatories the change in angle of incidence along the optical
path can be quite large. Changes in angle of incidence across a beam result in chromatic
polarization-dependent phase and amplitude aberrations. These aberrations tend to
decrease sensitivity to faint signals at small angular separations, which may limit
the total number of exo-Earths HWO is able to detect. We review efforts in modeling,
analyzing, and measuring the polarization of light in astronomical telescopes to better
understand polarization aberrations in HWO, and showcase the open-source software
packages we have built to support future investigations.
Meeting Id: 975 7234 8560; Passcode: 677943