text: i am interested in star hd 835 (the henry draper catalogue, and have located it via simbad. but.......? i have been unable to extrapolate its distance in lightyears as it is dimmer than ninth magnitude, and does not therefore appear in the lists on my stellarium software. its co-ordinates are, ra 00 12 39.8, dec: -29 20, 30. it is spectral type k5 with an apparent magnitude of 9.55 (and is a blue star). can anyone tell me how to work out this stars distance from us? but k5 means yellow, not blue (somewhat yellower than the sun).  anyway, assuming k5 is correct, and that hd835 is a main-sequence star, and not something weird like a yellowish "red" giant, then it would have an absolute magnitude of around 8, which means it looks like a magnitude 8 star from one parsec distance.  but since it appears a magnitude and a half dimmer, that means it's only one-fourth as bright as it would be at one parsec, so it must be twice as far away (inverse square law).  so its distance is about two parsecs, which equals 7 light-years.