Beehive Cepheid variable Hertzsprung-Russell diagram Hyades Messier catalog NGC POW camp Pleiades Seven Sisters absolute magnitude bastille binary star borstal borstal institution bridewell brig cell concentration camp condemned cell death cell death house death row detention camp double star dwarf star federal prison fixed star forced-labor camp gaol giant star globular cluster gravity star guardhouse house of correction house of detention industrial school internment camp jail jailhouse keep labor camp lockup magnitude main sequence star mass-luminosity law maximum-security prison minimum-security prison neutron star nova open cluster oubliette pen penal colony penal institution penal settlement penitentiary populations prison prison camp prisonhouse pulsar quasar quasi-stellar radio source radio star red giant star reform school reformatory relative magnitude sky atlas spectrum-luminosity diagram sponging house star star catalog star chart star cloud star cluster state prison stellar magnitude stockade supernova the hole tollbooth training school variable star white dwarf star