2 Observations and reductions

The observations were performed with the Strömgren Automatic Telescope (SAT) of the Copenhagen University Observatory at La Silla. The vast majority of the photometry was obtained during 20 nights in December 1997 - January 1998. Several stars, omitted during this run were included in our list of targets during December 1998. The selection of the targets is based on the PPM catalogue-South (Bastian & Röser 1993), including all stars of spectral types O and B in the field. The $uvby\beta$ compilation of Hauck & Mermilliod (1998) was used to exclude from the list of targets stars with already existing data. Since it would be of interest to compare the new data to other data sets, some stars in common with previous observations were, however, left in the list. In this way, 283 stars for uvby photometry and 225 for H$\beta$ photometry were included. 77 stars in the final sample are intrinsically luminous stars (Stephenson & Sanduleak 1971).

The selection of standard stars, observing procedures and transformations to the standard systems for the two observing runs are described in detail in Kaltcheva & Olsen (1999) and Kaltcheva et al. (1999) (Papers I and II). All observations in the present catalogue were made by the SAT in its fully-automatic mode. Details about the spectrometer, the observing procedure, and the fully-automatic mode are given by Olsen (1993,1994).

A circular diaphragm of 17'' was used. The number of photo-electrons counted was 100 000 in the y-channel and 70 000 in the $\rm {\beta_{narrow}}$-channel, except for a few of the faintest stars. The background was measured at each program star at a fixed offset. Before reductions, several sky measurements from a small area of the sky, and contiguous in time, were combined and then used on all stars in the area. Sky measurements contaminated by faint stars were eliminated in this process.

Figure 1: The differences in the V mag and the photometric indices in the sense (HM-SAT) plotted vs. the SAT values. Crosses are used for m1 and open symbols for c1

 

 

Table 3: Comparison of $\beta$ values obtained in this paper to other authors

N	$D(\beta)$	$D(\beta)$	Source
$\beta$		s.d.
14	0.002	0.012	Hill G., Perry C.L., 1969, AJ 74, 1011
15	-0.022	0.015	Graham J.A., 1970, AJ 75, 703
6	-0.005	0.017	Crawford D.L., Barnes J.V., Golson J.C., 1971, AJ 76, 621
3	-0.003	0.009	Feinstein A., 1974, MNRAS 169, 171
13	-0.010	0.017	Deutschman W.A., Davis R.J., Schild R.E., 1976, ApJS 30, 97
7	0.000	0.004	Gronbech B., Olsen E.H., 1977, A&AS 27, 443
22	0.002	0.019	Klare G., Neckel T., 1977, A&AS 27, 215
8	-0.031	0.034	Eggen O.J., 1978, AJ 83, 288
3	-0.004	0.002	Sinnerstad U., 1980, A&AS 40, 395
3	0.009	0.011	Eggen O.J., 1981, ApJ 246, 817
3	-0.017	0.019	Lindroos K.P., 1983, A&AS 51, 161
13	-0.005	0.010	Eggen O.J., 1983, MNRAS 204, 377
15	-0.004	0.011	Perry C.L., Landolt A.U., 1986, AJ 92, 844
5	0.004	0.007	Landolt A.U., Perry C.L., Levato O.H., Malaroda S.M., 1990, AJ 100, 695
4	-0.008	0.009	Stetson P.B., 1991, AJ 102, 589
6	0.012	0.010	Knude J., 1992, A&AS 92, 841
10	-0.007	0.010	Kaltcheva N.T., Georgiev L.N., 1994, MNRAS 269, 289
19	0.007	0.022	Corradi W.J.b., Franco G.A.P., 1995, A&AS 112, 95

 

 

Table 4: Comparison of V, b-y, m₁ and c₁ values obtained in this paper to other authors

N	D(V)	D(V)	D(b-y)	D(b-y)	D(m1)	D(m1)	D(c1)	D(c1)	Source
Vuvby		s.d.		s.d.		s.d.		s.d.
6	0.013	0.010	0.006	0.006	-0.012	0.006	0.021	0.005	1.  Gronbech B., Olsen E.H., 1976, A&AS 25, 213
14	0.032	0.007	0.013	0.003	-0.019	0.006	0.013	0.012	2.  Hill G., Perry C.L., 1969, AJ 74, 1011
3	-0.018	0.016	0.016	0.013	-0.024	0.011	0.013	0.010	3.  Vogt N., Faundez M.A., 1979, A&AS 36, 477
7	0.016	0.012	0.002	0.004	-0.019	0.017	0.028	0.011	4.  Eggen O.J., 1978, AJ 83, 288
3	-	-	-0.002	0.007	-0.004	0.010	0.014	0.003	5.  Sinnerstad U., 1980, A&AS 40, 395
3	-0.011	0.022	0.002	0.014	-0.039	0.012	0.041	0.012	6.  Lindroos K.P., 1983, A&AS 51, 161
16	0.007	0.018	0.009	0.004	-0.015	0.005	0.030	0.010	7.  Perry C.L., Landolt A.U., 1986, AJ 92, 844
5	0.004	0.006	0.007	0.004	-0.019	0.003	0.028	0.013	8.  Schneider H., 1987, A&AS 71, 147
6	-0.002	0.033	-0.009	0.007	0.001	0.013	0.008	0.015	9.  Crawford D.L., Barnes J.V., Golson J.C., 1971,
									AJ 76, 621
5	0.012	0.015	-0.007	0.011	-0.010	0.016	0.003	0.014	10. Schneider H., Weiss W.W., 1988, A&AS 75, 353
5	0.002	0.010	0.000	0.009	-0.011	0.014	0.017	0.021	11. Landolt A.U., Perry C.L., Levato O.H., Malaroda S.M.,
									1990, AJ 100, 695
18	0.000	0.012	0.011	0.004	-0.025	0.010	0.020	0.019	12. Corradi W.J.b., Franco G.A.P., 1995, A&AS 112, 95
4	0.012	0.002	0.010	0.003	-0.026	0.003	0.028	0.003	13. Stetson P.B., 1991, AJ 102, 589
6	0.015	0.020	0.006	0.011	-0.030	0.018	0.020	0.011	14. Knude J., 1992, A&AS 92, 841
10	0.007	0.009	0.009	0.005	-0.004	0.007	-0.002	0.008	15. Kaltcheva N.T., Georgiev L.N., 1994, MNRAS 269, 289
6	-0.003	0.019	-	-	-	-	-	-	16. Deutschman W.A., Davis R.J., Schild R.E., 1976,
									ApJS 30, 97
12	-0.007	0.024	-	-	-	-	-	-	17. Klare G., Neckel T., 1977, A&AS 27, 215
12	0.019	0.012	-	-	-	-	-	-	18. Eggen O.J., 1983, MNRAS 204, 377

Figure 2: The differences V-V(SAT) plotted vs. V(SAT) for the sources listed in Table 4

Figure 3: Difference V-V(SAT) plotted vs. (b-y)(SAT) for the sources listed in Table 4. The symbols are the same used in Fig. 2

Figure 4: The differences Delta (b-y) = (b-y) - (b-y)(SAT) plotted vs. (b-y)(SAT) for the sources listed in Table 4. The individual sources of the photometry are shown at the panels

Figure 5: The differences Delta m1, c1 equal to m1-m1(SAT) (crosses) and c1-c1(SAT) (open symbols) plotted vs. b-y(SAT) for the sources listed in Table 4. The individual sources of the photometry are shown at the panels