Nicolas-Louis de Lacaille discovered M83 = NGC 5236 = Lac I-6 = D 628 = h3523 in 1751-1752 with only a 1/2-inch telescope at 8x during his expedition to the Cape of Good Hope. He simply described a "small, shapeless" nebula. M83 is the only galaxy in Lacaille's list and its remarkable that it was discovered with so small an aperture. Charles Messier was barely able to view it from Paris, noting "It appears as a faint, even light, but is difficult to see with the telescope that the slightest illumination of the micrometer's crosshairs causes it to disappear. It requires considerable concentration to see at all."

William Herschel made two observations of M83: On 15 Mar 1787 (sweep 711) he logged "vB, a bright resolvable nucleus in the middle with F branches about 5' or 6' long, E sp-nf." On 5 May 1793 he logged "vB, a SBN with very extensive and vF nebulosity; it more than fills the field, it seems to be rather stronger from sp to nf. It may be ranked among the nebulous stars."

James Dunlop observed M83 on 29 Apr 1826 and recorded "185 Centauri is a very beautiful round nebula, with an exceedingly bright well-defined disk or nucleus, about 7 or 8 arcseconds diameter, surrounded by a luminous atmosphere or chevelure, about 6' diameter. The nebulous matter is rather a little brighter towards the edge of the planetary disk, but very slightly so. I can see several extremely minute points or stars in the chevelure, but I do not consider them as indications of its being resolvable, although I have no doubt it is composed of stars." His published position is off by some 12+ minutes in RA, but Glen Cozens found a copying error of exactly 13 minutes from his handwritten position. His original position is within 10' of center.

John Herschel's first observation from the Cape of Good Hope on 5 May 1834 reads "vB, vL, sbM to a centre equal to a star 9th mag, diam 8", of a resolvable character like a globular cluster, surrounded by an immensely large, extremely dilute almost equable light 7' or 8' diameter, somewhat oval, and passing with excessive suddenness into the central light."

William Lassell discovered the spiral nature using his 48-inch fork-mounted reflector on Malta in May 1862. He sketched M83 as an elegant three-branched spiral (Plate VII, Fig. 28, in Memoirs of the Royal Astronomical Society, Vol 36). The NGC description "3 branched spiral" refers to Lassell's sketch. It was also sketched by Turner as an elegant "S" shaped spiral on the unpublished Plate VI, figure 62 as well as by Pietro Baracchi in Apr 1885.

M83 has 6 known supernovae, the first (SN 1923A) found by Lampland on a photograph taken 5 May 1923 with the 40-inch Lowell reflector.

200/250mm - 8" (3/24/84): very bright, bright core, elongated, impressive.

300/350mm - 12" (6/29/02 - Bargo, Australia): this was my best view to date of M83 with a beautiful spiral structure clearly evident and multiple knotty arms. Well concentrated with a prominent core and very small nucleus. A very long, spiral arm is attached on the west side of the central core or bar but quickly bends to the north, becoming more spread out and diffuse. It continues to wind along the entire east side of the halo and fades out near a close double star, which is the middle of three collinear stars to the SE of the galaxy. Two other principal arms are visible - one is attached on the following end of the core and heads south, wrapping clockwise around the core towards the west. A third arm emerges from the core on the west side and winds clockwise towards the north. Offshoots of the main arms are difficult to trace and contribute to the general background glow of the halo.

400/500mm - 17.5" (5/10/86) : brighter arm or arc visible north of the core.

600/800mm - 24" (4/11/08 - Magellan Observatory, Australia): M83 resembled the photographic appearance in the 24" at 200x. The bright "bar" was elongated SW-NE and roughly 3'x1' in size with a well-defined bright, round core, 1' in diameter. The first prominent arm is attached at the northeast end of the bar and sweeps south (counter-clockwise) on the east side of the core, wrapping around the southeast side and spreading out a bit as it terminates to the south of the core (~3' from the center). This arm has a high contrast along its outer edge and a couple of faint stars or HII knots are visible near where it attaches to the bar. On the southwest end of the bar a second prominent inner arm emerges and abruptly wraps counter-clockwise around the galaxy on the west side as it heads north. This arm continues to wrap around the north side before spreading out on the northeast side and merging into the outer halo ~3.5' from center on the northeast edge of the halo. A third, more ill-defined arm, also emerges from the core on the south but sweeps more gently to the west (instead of heading north) on the outside of the second arm. It spreads out and fades into the general glow about 3.5' SW of center near a superimposed mag 12 star. Offshoots of the main arms are difficult to trace and contribute to the general background glow of the halo.

900/1200mm - 48" (4/7/13): During this observation of M83, I focused on the HII regions that light up portions of the remarkable spiral arms that emanate from the 3'x1' central bar. The bar is sharply concentrated with a small, intensely bright, 1' round core. At the northeast end of the bar a high contrast arm begins to sweep counterclockwise along the east side, ending up directly south of the core. Several knotty clumps were visible in the region where the arm is attached. First, at the northeast end of the central bar [1.2' NE of center] is NGC 5236:[dPD83] 42, a 10" HII knot. This designation is from a 1983 paper by de Vaucouleurs, Pence and Davoust that includes a map of the 60 brightest HII regions. Close east of this knot is #46, a 20"x10" elongated patch, situated where the arm begins to unfurl to the south [1.7' NE of center]. HII region #54 is another 12" knot a bit further southeast [0.6'] along the arm [1.9' ENE of center].

On the opposite southwest end of the bar a prominent second arm emerges and spirals out counterclockwise along the west side of the galaxy heading north and then spreading out as it curves east. The arm dims noticeably on the northeast side of the halo near a mag 13 star and has a low surface brightness as it continues south in the outer halo, heading towards h 4599, an 8" pair of mag 8.2/10.7 stars. Several knots are visible in this arm. As the arm emerges at the southwest end is #22 and #18, a small 10" knot [1.8' SW of center]. Close north is an elongated clump [2.0' WSW of center], ~25"x10", containing #13 and #15. Another elongated patch, 30"x10", containing #12 and #16, is 1' further north along the arm [1.9' WNW of center]. Additional HII regions were visible at the northern side of the arm; #39 and #43 are a close pair of small knots ~2.5' NNE of center. Further east along the arm [3.3' NE of center] is #56, another elongated patch, 20"x10".

A third, wider and more diffuse arm begins on the south side of the bar. It extends below the brighter arm on the west side, and sweeps more gradually, forming an outer western arm. This arm passes just north of a mag 12 star and ends about 4' W of center at a brighter, elongated patch that includes #2 and #3, as well as a mag 15 star.

48" (5/15/12): jaw-dropping view of M83, with the galaxy filling about 2/3 of the 375x field. I didn't take detail notes as we were looking for a recently discovered ultraluminous X-ray source (ULX), in which a companion star is orbiting a neutron star or black hole. We found a stellar or quasi-stellar object at the north edge of the central core, but this was likely a compact HII region (the ULX is ~1' E of the nucleus).

Notes by Steve Gottlieb