View Full Version here: : photovisual magnitude

05-10-2010, 12:13 AM
I've been looking for information on the "photovisual magnitude" (mpv) scale. As far as I understand it is obsolete but I would like to know if this is the same as apparent magnitudes (mv) or is there a conversion method?
Thank you,

05-10-2010, 11:10 AM
The photovisual magnitude is just how bright a star or object appears on a photographic plate that is sensitive to the predominant wavelength in the visual part of the spectrum (Yellow-Green....530nm). It's an obsolete term. We just refer to it as the visual (v) magnitude now.

Apparent magnitude is the magnitude of a star or object as it appears on a photographic plate, digital image or by visual observation. The absolute magnitude is a "calibration" of that object's brightness to how it would appear at a set distance from us....10 parsecs (32.6 light years).

13-10-2010, 09:56 PM
Many thanks, that helped clear up some questions at this end.