Equirectangular plot of declination vs right ascension of the Messier objects relative to the modern constellations, coded by type and apparent visual magnitude, with a dotted line denoting the ecliptic. Note that the right ascension axis increases from right to left to approximate the view of the night sky. Messier object data is from http://messier.seds.org/dataDec.html . Constellation boundaries are derived from ftp://cdsarc.u-strasbg.fr/pub/cats/VI/49/bound_18.dat with Ursa Minor's corrected to reach the north celestial pole. The Milky Way bitmap is from http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003572 (low-res magnitude 5 version). Thanks to Timwi for 4-colouring with each quadripoint having all colours.
Own work, http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003572
Cmglee