The nature of the relationship between visual brightness estimates for red stars and the corresponding V magnitudes has been investigated by comparing visual estimates in the American Association of Variable Star Observers database to photoelectric photometry of 39 semiregular variable stars obtained at Grinnell College over a 30 yr period. A general mathematical description of this relationship has been developed, but it applies only approximately for many individual stars because the actual relationship can be quite different for different stars. The overall trends should apply to visual magnitude estimates for red stars generally. These results are based on far more data over a wider range of color than was the case in earlier work and should provide a more robust description of the relationship between photometric measurements and visual estimates. A number of other issues related to visual magnitude estimates are also addressed.

红星的视觉亮度估计与相应的V之间的关系的性质通过比较美国变星观测者协会数据库中的视觉估计值与格林内尔学院在30年内获得的39个半规则变星的光电光度法，对星等进行了研究。已经开发出这种关系的一般数学描述，但它仅适用于许多单个恒星，因为实际关系对于不同恒星可能有很大不同。总体趋势应适用于一般的红星视觉大小估计。与早期工作相比，这些结果是基于更多颜色范围内的更多数据得出的，应该提供对光度测量和视觉估计之间关系的更可靠的描述。还解决了与视觉幅度估计有关的许多其他问题。