NGC/IC Project Restoration Effort

===== NGC 2403. See NGC 2253 and NGC 2404.

===== NGC 2403 48" (4/15/10): this amazing multi-arm spiral stretched across the entire 15' at 330x, with the major axis running NW to SE. A striking prominent spiral arm is attached near the NW end and sweeps counter-clockwise 180¡ along the northern side of the galaxy, tapering as it extends to a point roughly 5' SE of the core. The arm is widest near the NW end, where it begins sweeping east. A second inner arm attaches near the SE end of the main body and tightly hugs the southern side of the galaxy as sweeps to the NW side. A more ill-defined branch heads west from the SE end past a mag 11 star situated 2' WSW of the core. The field was too small to trace out the outer arms. Numerous HII splotches stained the surface and I only had time to quickly sketch the most obvious knots. The supergiant HII complex NGC 2404 located 1.7' ENE of the core and 1.5' NNW of a superimposed mag 10.5 star, appeared as a very bright, irregular, 20" knot. Hodge lists NGC 2404 as A67 in his 1985 paper "Stellar Associations in the Galaxy NGC 2403". On the NW side of the galaxy is a collinear string of 3 stars oriented NE to SW with an obvious collinear knot an additional 50" SW (SPC-44 in Sivan, Petit and Comte's 1990 "Optical HII Regions in NGC 2403"; VS 3 in VŽron and Sauvayre; and A14 in Hodge). Just north of the core are two HII knots, separated by 45" and both 12" in size. The western knot is catalogued as SPC-174 = VS 24 = A36 and the eastern knot as SPC-224 = VS 38 = A45 . On the SE side of the galaxy is a pair of HII knots separated by 40". The eastern knot is SP-346 = VS 51 = A80 and is situated 1.6' SE of the mag 10.5 star and the western knot includes SPC-318/321/322. At the SE end of the spiral arm that contains NGC 2404 is another 10" knot, which includes SPC-348/351/352 = VS 52 = A81. It can be pinpointed 1.0' NE of the mag 10.5 star. On the SE end of the galaxy a fairly faint, irregular knot (SPC-331/336/343 = VS 48/49 = A73) was noticed 1' W of a mag 14 star. 18" (3/19/04): at 160x, this chaotic spiral displayed a tremendous wealth of detail with two broad, diffuse spiral arms, dark lanes, mottling and a few obvious giant HII regions. A number of stars are superimposed including two mag 11 stars. I focused on observing the HII regions that were best viewed at 323x. The brightest is the HII complex NGC 2404 (VS 44 = SP 298) on the east side of the core 1.5' from center and 1.5' N of a mag 11 star to the SW of the core. This knot is fairly bright at 323x, perhaps 15" diameter and irregularly round. On the NW side of the halo is a collinear string of two stars along with a fuzzy knot (VS 3 = SP 44 = A14), oriented from SW to NE. This HII knot forms the SW end of the string and is clearly nonstellar at 323x, ~15" diameter. It can also be pinpointed 2.4' NW of the mag 11 star west of the core (middle of three in a E-W string). At the NNW edge of the core is a mag 13.5 "star" that does not focus sharply and appears to be another HII knot (VS 24 = SPC-174 = A36). Close following is a fainter, but definite nonstellar knot ~10" diameter (VS 38 = SPC-224 = A45). Finally, returning to star on the SW edge of the core, a fainter mag 14 star is close south with a weak nebulous glow attached (SPC-221/222/225). This region is also catalogued as A41 in Hodge's 1985 "Stellar Associations in the Galaxy NGC 2403" from PASP, 97, 1065 . 17.5" (2/28/87): very bright, very large, bright core, elongated 5:2 NW-SE, 15'x6'. Impressive galaxy with spiral structure clearly visible. Two spiral arms are attached at opposite ends of the central region and both wind almost 180¡. The tip of the northern arm ends at the emission nebula NGC 2404. Several stars are superimposed including two mag 11 stars. 17.5" (2/22/87): two spiral arms are visible on attached at the opposite sides of the galaxy and winding a half of revolution. The northern arm ends at the HII knot NGC 2404. The galaxy has a mottled appearance. 13" (1/11/86): spiral arm definite on the west side of the galaxy with a dark gap between this arm and the main body (core). This feature is very faint but definite with averted. 13" (12/22/84): spiral arm highly suspected attached at the west side winding along the north side to a faint knot = NGC 2404. 13" (1/28/84): very bright, large bright core. NGC 2404 is clearly visible as a faint, very small nebulous knot along the east side of the galaxy. Spiral structure (arms) is just suspected. On 3/24/84 the knot was difficult to view at 144x, but on 1/11/86 was fairly easy. 8" (1/1/84): bright, large, bright core, faint star superimposed, mottled?