Mccormick Photovisual Sequences.
C. A. Wirtanen, A. N. Vyssotsky · The Astrophysical Journal · 1945
A network of 329 photovisual magnitude sequences covering the sky from +75° to - 15° is presented in Table 2. Each sequence contains, on the average, 13 stars ranging from 6~3 to 10m5. Although the accuracy of the individual magnitudes is not high (p.e. = ±O'~O75), an attempt has been made to de- termine them in a fairly fundamental manner, so that the system would be as uniform and as close to the IPv as possible. Comparisons are given with various other catalogues of photovisual and visual mag- nitudes