SA 194-252 , the SIMBAD biblio

Four-colour and Hβ photometry is introduced for 594 stars earlier than G0 in the Kapteyn's Selected Area 194. The results give V, b-y, m₁, c₁, and β on the standard systems, with overall rms errors for one observation of one star of 0.009mag, 0.004mag, 0.006mag, 0.009mag, and 0.009mag, respectively. The data cover an area of about 5deg x 5deg and is intended for an investigation of the distribution of the interstellar medium toward the northern part of the Southern Coalsack and its surroundings. A comparison to earlier results obtained by other authors has shown that the c₁ indices obtained for the late type stars were underestimated, in average, by 0.020mag. Since such difference may account for an error of little more than 10% in the estimated stellar distances, a correction was applied to the c₁ index of these stars.