How to convert RC3 coded revised Hubble types into standard revised Hubble types The Third Reference Catalogue of Bright Galaxies (RC3; de Vaucouleurs G. et al. 1991) provides a *coded* revised Hubble type (Example: For NGC 1300, the coded revised Hubble type is ``.SBT4'') The coded revised Hubble type can be converted into a more standard revised Hubble type by using the tables in Section 3.2 of the Second Reference Catalogue of Bright Galaxies (RC2, de Vaucouleurs G. et al. 1976). For instance, NGC 1300 would be SBbc (rs). Below I provide a simple explanation of what each character of the coded revised Hubble type means, and hence, how it can be converted into a standard revised Hubble type. 1) Characters 1-2 ".L", ".E", ".S", ".I", = Lenticular, Elliptical, Spiral, Irr = S0, E, S, Irr, "CE", "CI" = dwarf elliptical, dwarf irregular = dE dIrr ".P", "P.", "R." = Peculiar P, Pseudo Outer ring , Outer ring = P (R') (R) Note: Peculiar galaxies may also be sometimes denoted by a "P" at the end of the coded Hubble type. 2) Subsequent characters a) If characters 1-2 are ".E' "cE" then subsequent characters represent the ellipticity e.g., .E0, .E0+, .E0-1, .E1-2, .E2, etc b)If characters 1-2 are ".S", ".L", ".I", "CI" then subsequent characters denote the following Bar types B X A = strongly barred, weakly barred, unbarred = B, AB, A Ring or spiral type R S T = R for inner ring, S for s-shaped, T for mixed (transition) = approximately r, s, (rs) Numerical index for Hubble type = 1 for a, 2 for ab, 3 for b, 4 for bc = 5 for c, 6 for cd, 7 for d, 8 for dm, 9 for m = 10 for Im, 11 for cI EXAMPLES ------------------------------------------------------- Revised Hubble Meaning Revised Hubble Type in RC3 Type in coded from standard form ======================================================== .PSBR2 Peculiar, Spiral with P SBab(r) strong bar, inner ring, type ab, -------------------------------------------------------- P.SBR2 Pseudo Outer ring (R') (R')SBab(r) Spiral with strong bar, inner ring, type ab -------------------------------------------------------- .SAS0 Normal, Spiral with SA0(s) no bar, s-shaped, type 0 -------------------------------------------------------- .SXT1 Normal, Spiral with SABa(rs) weak bar, ring/s-shaped, --------------------------------------------------------