J.H.Madler (double stars) Mac - Maclear (double stars) MACS - Massive Cluster Survey or Magellanic Catalogue of Stars MACHO — MACHO Project lensing events (Massive Compact Halo Object) MACHO-LMC — MACHO Project Large Magellanic Cloud Microlensing MACHO-SML — MACHO Project Small Magellanic Cloud Microlensing Maffei - Paolo Maffei (for example: galaxies Maffei 1 and Maffei 2 in Cassiopeia) Mailyan - (for example: Mailyan 44, aka Holmberg I / DDO 63 / UGC 5139, at 9h 40.5m / +71° 11' in Ursa Major) Malin - David Malin (for example: the largest galaxy known; Malin 1 in Coma Berenices) Mamajek (open star clusters) (for example: Mamajek 1 at 8:42:06 / -79:01:38) Markov (telescopic asterisms) (for example: Markov 1 in Hercules) MAXI — Monitor of All-sky X-ray Image Mayall - Nicholas Mayall (for example: globular star cluster Mayall II orbiting Messier 31, the Andromeda galaxy) Mayer (open star clusters) McC — McCormick Observatory Catalog MCG — Morphological Catalogue of Galaxies MCW — Morgan, Code, and Whitford Me - Merrill (planetary nebulae) Mel - Melotte Catalogue of open star clusters (Philibert Jacques Melotte) Mercer (for example: globular star cluster Mercer 3 in Scutum) MGC (globular star clusters) (for example: MGC1 in Pisces) Mh - O.M.Mitchel (double stars) Mil - J.A.Miller (double stars) Miller (open star clusters) (for example: Miller 1 at 9:25:42 / -53:14:00) Milb - W.Milburn (double stars) MlbO - Melbourne Observatory, Australia (double stars) Mlf - Frank Muller (double stars) Mlr - Paul Muller (double stars) Moffat (open star clusters) (for example: Moffat 1 at 16:01:30 / -54:07:00) Moitinho (open star clusters) (for example: Moitinho 1 at 8:19:17 / -45:12:30) MPC — Minor Planet Circulars contain astrometric observations, orbits and ephemerides of both minor planets and comets Mrk - Benjamin "Benik" Egishevitch Markarian (open star clusters) MSH — Mills, Slee, Hill - Catalog of Radio Sources Muzzio (open star clusters) (for example: Muzzio 1 at 8:57:12 / -47:46:00) MW — Mandel-Wilson Catalogue of Unexplored Nebulae, not in SIMBAD yet MWP - Motch-Werner-Pakull (planetary nebulae) MyCn - Mayall-Cannon (planetary nebulae) Mz - Menzel (planetary nebulae) N N - (for example: N 164 nebula in Dorado) Na - Nassau (planetary nebulae) Naillon - (telescopic asterisms) (source: Bruno Alessi's list) N30 — Catalog of 5,268 Standard Stars Based on the Normal System N30 Neckerman (telescopic asterisms) (for example: Neckerman 1, aka Kemble 2 "Little Cassiopeia"). NED - NASA/IPAC Extragalactic Database Negueruela - (Ignacio Negueruela) NeVe