Abs. absorption abun. abundance(s) AD angular diameter ampl. amplitude An Anonymous AsB asymptotic branch Ass association B Bailey b blue BD Bonner Durchmusterung br. bright c centre CAN cluster associated with nebula Cat. Catalogue CE colour excess CI colour index cl. cluster classif. classification col. colour comp. compressed cons. considerably Cr Collinder descr. description diagr. diagram Diss. dissertation Dist distance Eff. effective ev. evolution Ex. extragalactic ex. example ext. extremely extend. extended f. faint foll. following gal. galactic GB giant branch GCl globular cluster glob. globular gr. group grad. gradually HB horizontal branch HD Henry Draper Catalogue Hol. Holetschek IM index of metallicity int. interval intst. interstellar invol. involved ion. ionized ir infrared irreg. irregular l. line LD linear diameter Lk Lundmark L(M) luminosity function LMC Large Magellanic Cloud M Messier M absolute magnitude MC Magellanic Clouds Mel Melotte mg magnitude mid. middle MS main sequence N, n number Neb. nebula neu. neutral nonexist. nonexistent nor. north obs. observation(s) OCl open cluster P part p position p. page part. partially pe photoelectric per. period pg photographic phot. photograph pl. plate pret. pretty prop. mot. proper motion pv photovisual r red Rb Raab red. reduction rel. relative resol. resolvable rev. review rG red giant RN reflection nebula rot. rotation rou. round RV radial velocity S series Sh Shapley sm. small SMC Small Magellanic Cloud sp. spectrum st. star stel. stellar st. gr. stellar group Sup Supplement Tr Trumpler tv television uv ultraviolet V volume var. variable vel. velocity vis. visual y yellow yr. year(s) ZAMS zero age main sequence