Daily Archives: 2025-06-09

Spider Globular Cluster

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Messier 4 – Spider Globular Cluster in Scorpius – OSC v3

More processed OSC data with the ASI 2600 MC Duo and the IAS 20″ telescope AK3, featuring the globular cluster Messier 4 aka NGC 6121.

Notable change to my previously shown OSC workflow: I used “K2V star” as the white reference for SpectrophotometricColorCalibration. Standard “Average spiral galaxy” yielded stars, which were too “golden” for my taste, thus this bluer/colder rendition.

See also at Astrobin.

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