The m x1 x2 x3 photometric system

Basic Reference

Neff J.S., Travis L.D. 1967, Astron. J. 72, 48


Observations of standard stars are presented to define a new intermediate bandpass photometric system. A comprehensive description of the instrument, reduction procedures and calibration procedures is given, since some of the methods are new. Considerable effort was made to remove or reduce all sources of error in the photometry. Typical mean errors of a single observations in m(0.55), x1 = m(0.47) - m(0.55), x2 = m(0.37) - m(0.47), and x3 = m(0.33) - m(0.37) are 10.9, 12, and 13 thousandths of a magnitude, respectively. A preliminary absolute flux calibration is given, based on scanner observations of Willstrop and Code. An appendix contains a detailed treatment of the second-order terms in the absolute calibration and in atmospheric extinction. This paper is the second in a series on this photometric system. Additional papers will be concerned with applications of the system to stellar classification and to the study of the physical properties of variable stars.


Access to the data and references

Asiago Database on Photometric System (ADPS)

Indices and Parameters

m, x1, x2, x3


Max transmission : 3350 Å ; Equivalent rectangular bandpass : 343 Å
Max transmission : 3690 Å ; Equivalent rectangular bandpass : 145 Å
Max transmission : 4680 Å ; Equivalent rectangular bandpass : 193 Å
Max transmission : 5450 Å ; Equivalent rectangular bandpass : 217 Å


RCA 1P21
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Last update: 13 September 2002