Open-shutter darks for removing y-band stray light in Hyper Suprime-Cam
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LEDs in an encoder in HSC are producing stray light on the detectors,
producing the "Eye of Y-band" feature. It can be removed by
subtracting open-shutter darks. However, because the pattern of stray
light varies with rotator angle, many dark exposures are required.
To reduce the data volume for the darks, the images have been
compressed using wavelets. The code used to construct these is at:

    https://hsc-gitlab.mtk.nao.ac.jp/sogo.mineo/ybackground/

A brief report on subtraction of this stray light is available from:

    https://hscdata.mtk.nao.ac.jp/hsc_bin_dist/4fc0f523/

The original version of the compressed data files is available from:

    https://hscdata.mtk.nao.ac.jp/hsc_bin_dist/4fc0f523/yb-dictionary-6-0.tar.xz

The data in this directory is the same as the original version, except
the directory structure has been reorganised.

Thanks to Sogo Mineo (NAOJ) for providing the data and code to
perform the stray light removal.