NGC 6530 and Barnard 86

Constellation: Sagittarius

NGC 6520 is an open cluster in the constellation of Sagittarius. It is located approx. 5’235 Ly from Earth. This is a young cluster with age estimates between 150 to 190 million years. However, the presence of stars with a spectral class of B4 and B5 suggest a much younger age of 60 million years. Just to the west of this cluster is the dark nebula Barnard 86 (a.k.a. the Molecular Cloud PGCC G002.85-02.75), also known as the Ink Spot, which is most likely unrelated to the open cluster. Link to interactive sky chart.

Dates:

Data acquired remotely in July and August 2025 using Martin’s equipment.

His telescope is located in Chile (Observatorio El Sauce).

Colour palette is HaRGB.

Telescope & Mount:

PlaneWave CDK17 (F6.8) on a Software Bisque Paramount ME mount.

Imaging:

Camera: SBIG STXL11002, FW8G, AO

Data:
Astrodon Red: 94x180s
Astrodon Green: 83x180s
Astrodon Blue: 81x180s

Astrodon Ha: 20x1800s

Total integration time: 22h 54′