The DAO photometric system

Basic Reference

Hill G., Morris S.C., Walker G.A. 1971, Astron. J. 76, 246


Forty-nine stars uniformly distributed in right ascension and north of declination -10 deg. have been observed over the last two years an average of 40 times each in the five-color system developed at the Dominion Astrophysical Observatory. The colors are measured with a simultaneous, four-channel photometer which isolates the Balmer continuum (35), the higher members of the Balmer series (38), regions matching the B (44) and V (54) filters of Johnson and Morgan, and two regions (42 and 56) formed by masking half of the 44 and 54 regions. The stars from an unreddened spectral sequence from O9 to K7 and the observations have been reduced to a self-consistent system. The standard values of the colors are presented together with the transformation of c(44-54) to B-V. The zero points for the c(35-44), c(38-44), and c(38-42) colors have been set at the minima in the plots of these colors against B-V near B-V=0. The standard deviation of the adopted means for each color is generally about 0.002. Results for cluster sequences and program stars will be presented in later papers together with detailed discussions of the astrophysical significance of the colors.


Access to the data and references

Asiago Database on Photometric System (ADPS)

Indices and Parameters

C35-44, C38-44, C38-42, C44-54 C45-56


35 :
Wavelength limits: 3400 - 3600 Å
38 :
Wavelength limits: 3700 - 3850 Å
42 :
Wavelength limits: 3900 - 4400 Å
44 :
Wavelength limits: 3900 - 4900 Å
54 :
Wavelength limits: 5050 - 5770 Å
56 :
Wavelength limits: 5410 - 5770 Å



To (B-V) in the Johnson system:

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Last update: 21 May 1996