NGC 6188 and NGC 6193 (Caldwell 82)


Click here for full resolution image

NGC 6188 is an emission nebula in the constellation Ara. This image also shows the open cluster NGC 6193 (off center, near the bottom, with the bright pair HD150136 and HD150135, both O-type stars). In fact, it is the ultraviolet light coming from the stars in that cluster, that fuels up the ionized hydrogen (HII, red) emission that we can see. The strong stellar winds from the stars in the cluster shape the nebula. This narrowband image has been processed as to reproduce the nebula’s visible spectrum. It shows a small patch (“wisps”, is probably a better description), that is brighter in OIII light, located between HD150136 and the nebula’s rim, and that betrays its presence by its soft bluish tint. This nebula has been repeatedly related to another open cluster, NGC 6167, located about 1.5 degrees south of it, due to its probable role in triggering the star formation that originated NGC 6193.

This image has been completely reprocessed, because the older version did not have the right proportion of OIII (Blue+Green).

Additional Information


Name(s): NGC 6188 and NGC 6193 (Caldwell 82)

Type: Emission Nebula

RA:  16h 40m 29s

Dec: -48ΒΊ 46’ 53”

Constellation: Ara

Size (arcmin): 20×12

Magnitude: +5.2

Distance: 3,800 ly


Date: 2016-03-23 thru 2016-04-03

Location:, SSO near Coonabarabran, NSW Australia

Size (arcmin): 37×36.5

Telescope: Planewave CDK 20” f/6.8

Camera: SBIG STX16803 (4096x4096pix)

Guiding: Astrodon MonsterMOAG off-axis guider

Total exposure: 19 hours (Ha: 9.5 h; OIII: 8 h; RGB: 1.5 h, only stars)

Processing: CCDStack, Photoshop CC 2016

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