. Transformations for very red stars are determined separately from
other data.

**Meylan G., Hauck B.** (A&A Suppl. 46, 281

## Abstract

The relations between temperature parameters of various photometric systems
are given. The photometries concerned are the following: UBVB1B2V1G (Geneva),
UBV (Johnson), uvby-beta (Strömgren), UPXYZVS (Vilnius), UBVRIJKLMNH (Johnson),
UVBGRI (Stebbins and Whitford). The effects due to the different luminosity
classes and to blanketing (Am, Ap and population II dwarf stars) are taken
into account.

**Natali E., et al.** (1994, A&A 289, 756)

## Abstract

We present an analysis derived from the UBVRI photometry of 12 open clusters,
that shows a linear relationship between the color indices (B-I) and (B-V).
Due to this characteristics the (B-I) color index is a more sensitive estimator
of the effective stellar temperatures with respect to the widely used (B-V),
and it is less affected by the absorption bands of H2 molecules in low mass
stars. Furthermore, from the two colors (B-I) vs (B-V) diagrams we derive
a new method yielding a parameter that estimates the interstellar
reddening fro each cluster.

**Ruelas_Mayorga R.A., Noriega-Mendoza H.**
## Abstract

A set of infrared standard stars for the South African Astronomical Observatory
(SAAO) are observed from the Observatorio Astronomico Nacional (OAN) located
at San Pedro Martir (SPM) in northern Mexico. A number of linear transformation
equations is obtained; in them, there is a slight need for a colour term which
implies that both sets of filters have slightly different values for their
effective wavelengths. Values for the OAN mean extinction coefficients are
calculated. They are larger that the values reported in Carrasco et al. (1991);
they might, however, be due to the ash and debris deposited on the atmosphere
by recent volcanic eruptions. We also calculate a set of colour transformations
to the homogeneous IR photometric system proposed by Bessell and Brett (1988).

**Taylor B.J. ** (1986, ApJS 60, 577)

## Abstract

Transformation among *VRI* systems are commonly beset by Paschen-jump
effects, for which fully satisfactory allowance has not previously been made.
This paper describes two new techeniques which are based on the work of
Gutierrez-Moreno, and which allow fully for the effects of the Paschen jump.
Values of *E(V-R)/E(B-V)* and *E(R-I)/E(B-V)* are also given for
the Cousins system for a wide range of temperatures. These and the new
techniques contribute to a set of new transformation relations which apply for
most *VRI* systems; the status of the remaining systems is reviewed,
and future work needed for them is described. Two major sources of Cousins
*VRI* data underlie the new relations; the consistency of these sources
is reviewed and found generally satisfactory, although more work on this
question is needed. Finally, three tables of transformed standard-star and
other data are given for the Cousins and Johnson systems, and a description
of ways to reproduce the latter is presented.

**Turner D.G.** (1990, PASP 102, 1331)

## Abstract

Transfromation relations are derived for the conversion of Stromgren colors
for early-type stars into equivalent Johnson system colors. The relation
*(U-B) = 0.675 (u-b) - 0.938 *

is valid for O and B stars of all luminosity classes and A and F stars of
luminosity classes III to V. The relation

*(B-V) = 1.584 (b-y) + 0.681 m1 - 0.116*

is valid for O and B stars of all luminosity classes and A stars of luminosity
classes III to V. No significant reddening corrections appear to be necessary
with these relations, which are accurate to 0.016 and 0.022 in the transformed
values of *(B-V)>* and *(U-B)*, respectively. Examples are given
of color-dependant and magnitude-dependent effects in published UBV data.
Such problems have important consequences for the distance scale of cluster
cepheids.

mermio@scsun.unige.ch

Last update: 7 Novembre 1995