Week 25 of the Early Operations system optimization period
Pre-LSST observations were the main on-sky activity of the week as the team continues offline data analyses, feature development, and preparing a next round of on-sky engineering tests to improve the delivered image quality.
A total of ~3700 pre-LSST visits were acquired from 10-15 April, including more than 50 visits for the COSMOS Deep Filling Field that produced alerts. No on-sky observations were acquired on 16 April while the team worked on multiple closed-dome engineering tasks. The delivered image quality was generally similar to that reported last week. The team continued performing parallel tests of the dome ventilation and thermal environment during the pre-LSST observations, for example, periodically opening and closing the dome louvers during nights with higher than average wind speeds to examine the impacts on delivered image quality.
The team tested an updated configuration for the Active Optics System (AOS) that applied calibrated offsets for the “target” optical state for each of the four individual corner wavefront sensors to improve the optical modeling, and hence the uniformity of the PSF delivered across the focal plane.
The next week is expected to include a comparatively larger fraction of dedicated on-sky engineering tests relative to the previous two weeks.
The currently installed filter set is ugriz, with a filter swap to exchange u for y planned for 21 April.