2. Astronomical Notices.

Abstract

These Notices were chiefly derived from the ordinary correspondence of the Royal Observatory of Edinburgh, from the important character of some of which Professor P. Smyth hoped that extracts from the best of the letters might be of interest to the Society.He alluded first to the astronomers of the United States, a large and increasing body, of no mean order of excellence already, and of the richest promise. Professor Loomis' recent work, which was exhibited, gives sufficient facts to prove the above statements.

Photoelectric $uvby-\beta$ photometry of the open cluster NGC 2422

“…A comparison of Shobbrook's V magnitudes with those of Mermilliod's (1976) and Smyth & Nandy's (1962) gave excellent linear relations. Correlation coefficients were of R 2 equal to 0.999 and 0.853, respectively.…”

“…We carried out further comparisons of the photometric data from Shobbrook (1984) and the present paper to the previous photometric data of NGC 2422, both photographic (van Schewick 1966Smyth & Nandy 1962) and photoelectric (Hoag et al 1961, and the compilation of Mermilliod 1976). The following was found:…”

“…Correlation coefficients were of R 2 equal to 0.999 and 0.853, respectively. Problems arose, however, when the b − y colour index of Shobbrook was compared to the B − V values of Mermilliod (1976) and Smyth & Nandy (1962). In each case the correlation coefficients were rather poor, R 2 equal to 0.647 and to 0.837, respectively.…”

“…To begin with, a homogenization of the identification had to be done since each previous observer lists the observations carried out with different identification numbers. The observations by Nissen were given in x and y coordinates from the map of Hoag et al (1961); Shobbrook (1984), on the other hand, gives his data in van Shewick's and Smyth & Nandy's numbers; Smyth & Nandy (1962) report their own identification chart. Hence, in view of this chaos, we have constructed a cross identification table (Table ??)…”

“…In view of this, and as a part of a larger research project, the open cluster NGC 2422 was observed through Strömgren photometry to first identify member stars as well as to determine physical characteristics that could differentiate the causes that provoke pulsation in the stars. In the past, several papers reporting photoelectric photometry have been devoted to NGC 2422: Hoag et al (1961) presents UBV photometric values for 20 stars and photographic photometry for 95 stars; Smyth & Nandy (1962) (hereinafter S & N) report photographic photometric values of 81 stars in three colours and a distance modulus of 8.4 mag considering both their data and that of Hoag et al (1961). A thorough compilation of open clusters, including NGC 2422, was made by Mermilliod (1976).…”