Likely lens arc


It’s interesting that the HSC DR2 images seem to be much more sensitive in the blue than DR9, so such features show up much more clearly. The better resolution helps too.

DECam has 520 megapixels vs Hyper-Suprime’s 870 megapixels. Its higher resolution at every colour. But yeah, good for lenses for sure.

It’s a combination of things: HSC has pixels 0.168", while DECam is 0.262", so better max resolution, combined with a better site: HSC is on the Subaru telescope on Maunakea, while DECam is on the Blanco telescope on Cerro Tololo.

Also, the HSC images are longer exposures (and on an 8m). Of course, the HSC-SSP survey covers a much smaller area!

Because of that extra sensitivity, the HSC viewer layer has a different stretch – similar to cranking up the “Brightness” slider.


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