It could be known, faint and messy arc ) like

https://www.legacysurvey.org//viewer/?ra=197.1898&dec=-0.7883&layer=hsc-dr3&zoom=15

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And a side note, What is that bright blue dot on the upper right of the image? An artifact?.. Any ideas? @nico @dstn @ChrisSnell88

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I’ve posted this object before & similar to you, was unsure if it was lensing or chance alignment ~ on DR9/DR10 it looks like lensing ~ with the higher image quality of HSC, it looks like individual background objects ~ as for the blue object, it doesn’t appear on the DR releases, so it ‘could’ be a photographic/sensor anomaly

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Yup, anything ‘pure blue’ like that is very likely to be either an artifact (cosmic) or a transient (asteroid, etc)

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Both, Thanks for your feedback

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That shape and color is classic asteroid in the HSC data

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