The r, r8, r9, i photometric system

Basic Reference

Argue A.N. 1967, MNRAS 135, 23


Red and infra-red magnitudes and colours for about 300 F, G and K type stars were measured at Kitt Peak National Observatory, Arizona. The photometer consisted of a 16 in. (40 cm) Cassegrain reflector, an RCA 7102 photomultiplier and the following filters: a lambda = 6900A interference filter (r), a Schott RG8 optical glass, a Schott RG9 and a lambda = 1.00 mu interferences filter (i). The natural r, (r-rg8) and (r-rg9) scales show good agreement with the R and (R-I) scales of Kron et al. for the F, G and K type stars but not for earlier types. The standard error for a simple difference from Kron, excluding the early types, is 0.022 in r, 0.015 in (r-rg8) and 0.016 in (r-rg9).

There is also good agreement between (r-i) and the (R-I) of Arizona Tonantzintla after a linear transformation has been applied to (r-i). Again types earlier than F have to be excluded, and the standard error of a simple difference then is 0.018.


Access to the data and reference

Asiago Database on Photometric System (ADPS)

Indices and Parameters

r-rg8, r-rg9, r, r-i


    r   : Interference
    rg8 : 2 mm Schott RG8 
    rg9 : 2 mm Schott RG9
    i   : Interference

Transmission curves


RCA 7102
Please, send your commentsto
Last update: 21 May 1996