> with the image plane rotated differently relative to the CCD plane in each exposure LSST is a alt/az telescope. The earth rotates. The sensor plane must ro

> with the image plane rotated differently relative to the CCD plane in each exposure LSST is a alt/az telescope. The earth rotates. The sensor plane must rotate during the exposure to prevent stars from streaking, which it accomplishes via this platform: https://docushare.lsstcorp.org/docushare/dsweb/Get/Document-21544/ https://docushare.lsstcorp.org/docushare/dsweb/Get/Document-... The fact that the sensor rotates without the spider rotating also spreads out the diffraction spikes. But that rotation is limited, so between different exposures with different filters the image plane will be rotated relative to the sky. As the quote goes the change in orientation has benefits for controlling systematics..