[]For observations with Hipparcos, and for the preparatory numerical simulations of the mission, magnitudes at maximum and minimum luminosities were computed from the available luminosity curves (Mennessier & Figueras 1989). However, it was considered more useful to the future user to give here the magnitudes at maximum and minimum luminosities, rather than the magnitudes. These magnitudes are those of the GCVS except for some stars for which more precise observations were available, and for the Mira stars. Indeed the GCVS gives the maximum and minimum magnitudes observed for each star. Due to the significant variability of Miras from one cycle to another one, it was considered more appropriate to give here the mean magnitudes of the luminosity extrema. A comparison of GCVS magnitudes with the mean magnitudes of the luminosity extrema, obtained from 30 years of observation for about 200 Miras by Campbell (1955), gives the following statistical relations (where is the period, and and are the magnitudes at maximum and minimum luminosities given in the GCVS respectively):

mer 16 nov 15:51:31 MET 1994