IC 2948, a mosaic


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This is another image of a fragment of IC 2948 in this web site. The previous three show the main nebula and the Bok globules (corresponding to the left side of this image),  the “Liberty Bell Nebula”  (corresponding to the right side of this image), and the whole, wide field, nebula.


IC 2948, is a large emission nebula also known as the “Running Chicken Nebula” and usually described as an “almost featureless emission nebula”. True as it may be in RGB images, this emission nebula is very rich in details and with a remarkable 3D appearance in narrowband images. Located in the constellation Centaurus, this nebula was not discovered until the beginning of the 20th century (1908). It has a very low surface brightness, and one of its most remarkable features is the presence of several “Bok globules”. These globules are small dark nebulae that contain molecular hydrogen gas as well as helium and variable amounts of silicate dust (usually around 1-3%). The globules are associated to star birth, and quite frequently (about 40% of the cases, according to Launhardt et al.) they provide double or multiple stars. None of the globules in this nebula has been detected in the active process of generating a star. The first astronomer to describe them was Bart Bok (together with Edith Reilly) in 1947 (Astrophysical Journal, vol. 105, p.255). The globules of, specifically, this nebula were discovered by David Thackeray and are also known as “Thackeray’s globules”. The associated open cluster powering the emission nebula is IC 2944, also known as Caldwell 100. It is also remarkable the emission in OIII wavelength, seen here as whitish-blue wisps.

This two-pane mosaic, a joint project with Christian Sasse, has been taken with narrowband filters and processed trying to reproduce the natural spectrum of the nebula.


Additional Information


Name(s): IC 2948. The Running Chicken Nebula

Type: Emission Nebula

RA:  11h 36m 36s

Dec: -63º 02’ 00”

Constellation: Centaurus

Size (arcmin): 75×75 arcmin

Magnitude: +4.5

Distance: 6,500 ly


Date: 2023-02-01 to 2023-02-26

Location: Obstech, Río Hurtado, Chile

Size (arcmin): 64×28 arcmin

Telescope: 24” f/6.5 Reflector

Camera: QHY 461 (11760x8896pix)

Guiding: off-axis guider

Total exposure: 54 hours (Ha: 25h 20m; OIII: 22h 40m; RGB: 6h)

Processing: CCDStack, PixInsight (one process) and Photoshop CC 2023

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