M 83-NGC 5236-Southern Pinwheel Galaxy


Click here for full resolution image

M 83 is a barred spiral galaxy located 15 million light years away in the constellation Hydra. This galaxy is clearly smaller than the Milky Way (about one fourth its diameter) and hosts about 40 billion stars. This galaxy also receives the nickname “Thousand Ruby Galaxy” due to the high number of red HII clouds in its arms. The galaxy itself was discovered by Nicolas Louis de Lacaille in 1752 (from the cape of Good Hope) and it is the southernmost object in Messier’s catalogue. According to K. L. Barnes (The Astrophysical Journal, 789:126 (10pp), 2014 July 10), this galaxy has a very faint but wide external star halo, with a star stream that is an extension of its spiral structure. This star stream (discovered by D. Malin in 1997) even receives a separate name: LEDA 166170. Barnes and her colleagues made use of NIR imaging (Spitzer Space Telescope) to get a better insight into this highly reddened star stream. There are several professional images (meaning taken with professional equipment) of this star stream, and one of them was selected as an APOD on 2014 Jan 17.

Specifically that image was obtained by blending images from the 1.2M UK Schmidt Camera, the 8.2 M Subaru Telescope (NAOJ), the European Southern Observatories VIMOS/VLT, 2.2-meter Max Planck-ESO telescope, as well as the Hubble Space Telescope. Up to my knowledge, there was not yet any amateur color image of M 83 that included this star stream (there is a previous monochrome image taken by the extraordinary astrophotographer Jay GaBany). This one could be it. The image in this website has been obtained by blending images from two different (amateur) telescopes (details below). The Halpha images were added in order to enhance the numerous HII clouds.

Additional Information


Name(s): M 83; NGC 5236; Southern Pinwheel Galaxy

Type: Barred Spiral

RA:  13h 37m 00s

Dec: -29ΒΊ 51’ 55”

Constellation: Hydra

Size (arcmin): 13×11

Magnitude: +7.5

Distance: 15 million ly


Date: Several during Apr-May-Jun-July 2016

Location: iTelescope.net, SSO near Coonabarabran, NSW Australia

Size (arcmin): 36×36

M83 and the starry background

Telescope: Planewave CDK 20” f/6.8

Camera: SBIG STX16803 (4096x4096pix)

Guiding: Astrodon MonsterMOAG off-axis guider

Total exposure: 17.5 hours (Ha: 3hs; L: 4.25hs; RGB: 10.25hs)

Star Stream LEDA 166170

Telescope: ASA 17″ (406mm, f/3.5) astrograph

Camera: Apogee Aspen CG16070 (4864 x 3232 pix)

Guiding: Yes

Total exposure: 4h10m (L: 10x10min; RGB: 10x5min each)

Processing: CCDStack, Photoshop CC 2016 and PixInsight

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