The measurements were carried out at the 1 m telescope of the Purgathofer Observatory (Klosterneuburg, N/W of Vienna) by one of us (RP). The photometer includes an EMI 6256B photomultiplier Peltier cooled and operated at 1170 V, and a rapidly rotating filter wheel which nevertheless stops for 60 milliseconds at each filter and moves during 20 milliseconds to the next one. Thus, one turn of the filter wheel takes nearly half a second (480 milliseconds). Since the individual integrations of usually 200 turns of the wheel were coadded in each filter, the results should be practically simultaneous.
| Filter |  [nm] | HW[nm] |  [%] | type |
| u | 352.6 | 16.0 | 42 | Schott UV-DAD |
| v | 410.1 | 21.4 | 43 | Schott DMZ |
| b | 467.0 | 19.5 | 63 | Schott DMZ |
| g1 | 501.7 | 11.0 | 82 | Anders, Germany |
| g2 | 521.2 | 12.0 | 82 | Anders, Germany |
| y | 547.3 | 18.8 | 58 | Schott DMZ |
The filter set is presented in Table 1 (click here).
A detailed description of the photometer has been given by Pressberger
& Stoll (1993).
Because of the bright sky of nearby Vienna a rather narrow diaphragm
of 7
was used. Therefore, special care was taken to
recenter the star under observation at the beginning of each series
(lasting about 100 seconds).
The programme stars were observed only on one night each, usually by
two sets of filter measurements, but sometimes also 3 and very
rarely 4 sets. The dead time correction was 65 nanoseconds.
In what follows we will present all photometric values in the
Strömgren and 
systems in units of 0.001 mags.
Table 2 (click here) contains the list of observing nights with average external
accuracies of the Strömgren parameters and (for non-peculiar
stars) together with the zero points of the normality line.
The external errors were derived from the differences of observed and
published Strömgren indices. It is very instructive to notice that
the average nightly scatter of values for non-CP2 stars (=
practically normal stars where the small number of deviating cases among the
other groups discussed below was disregarded) on 9 nights is smaller
than 4 mmags and only on 4 nights between 4 and 5 mmags. This
accuracy is nearly identical with that obtained by Maitzen
(1976) in his introductory paper on photometry where he could
rely on the excellence of the Chilean Atacama dessert sky (albeit in
traditional photometric observing mode).
The obviously larger average errors in the Strömgren parameters are
due both to their definition (implying the influence of atmospheric extinction
not present in ) and to the error level contained in the
published values. In some cases intrinsic variability may also have
contributed to this aspect.
Table 3 (click here) lists the differences of the published Strömgren
indices and our own values. Figure 1 (click here) shows the histogram for the
values for which we obtain a standard deviation of
6.8 mmags from a Gaussian fit for 110 stars.
Since according to Table 2 (click here) different
average night deviations have been obtained, it is not surprising that
the histogram is not perfectly approximated by a Gaussian distribution.
For the 
values we calculate 7.1 mmags as standard deviation
for 109 stars (we discard the deviating value for HD 209711 discussed
below). For the case of the c1 parameter we derive 9.5 mmags (again
for 110 stars).
The values yield a much better Gaussian fit with corresponding
standard deviation of only 3.1 mmags.
Figure 1: Histogram for all values from
Table 3 (click here)
Table 4 (click here) exhibits the results of our Strömgren and photometry
together with their mean errors (i.e. internal precision
based on the individual observations during the relevant night).
The values were obtained as usual by forming the difference
between the observed a-value and the a0-value of the
normality line at the same b-y as the concerning star. The normality
line, i.e. the locus of non-peculiar stars in the a vs. b-y diagram,
could be represented by a straight line with essentially constant
slope but slightly varying zero point ai (see Table 2 (click here)).
| night | yymmdd | ai |  |  |  |
| |
| 1 | 930320 | 0 | 10.5 | 7.4 | 7.7 | 3.7 | |
| 2 | 930416 | 0 | 6.8 | 7.0 | 4.6 | 3.1 | |
| 3 | 930420 | 2 | 7.3 | 8.9 | 8.3 | 4.9 | |
| 4 | 940403 | 5 | 9.7 | 6.3 | 12.3 | 4.1 | |
| 5 | 940407 | 11 | 8.4 | 5.8 | 13.3 | 2.3 | |
| 6 | 940420 | 11 | 5.2 | 9.3 | 9.3 | 3.7 | |
| 7 | 940503 | 11 | 5.5 | 8.3 | 9.0 | 3.5 | |
| 8 | 940513 | 9 | 16.5 | 10.2 | 14.4 | 5.0 | |
| 9 | 940601 | 5 | 5.0 | 13.9 | 19.4 | 4.4 | |
| 10 | 940929 | 12 | 10.3 | 14.2 | 11.3 | 2.3 | |
| 11 | 941009 | 12 | 4.5 | 8.1 | 7.7 | 3.7 | |
| 12 | 941010 | 12 | 6.5 | 10.0 | 18.6 | 3.3 | |
| 13 | 941025 | 5 | 5.1 | 11.9 | 20.8 | 2.6 | |
| 14 | 941201 | 8 | 6.2 | 11.0 | 32.3 | 4.6 |
The individual normality lines can thus be represented by:
The parameters of those normality lines were fixed by measurements of a
sample of 12 non-peculiar stars. As explained below, the majority of
Am, HgMn and He abnormal stars line up very closely to the normality
lines and thus reinforce the determination of the null-line of peculiarity.
Our sample of peculiar stars can be characterized by the following criteria:
.
From
reasons concerning airmass and the southern sky illumination by the city
of Vienna we set a lower limit to declination at 0.
Reddening corrections in b-y had to be applied only to very few stars
of our sample in order to obtain intrinsic values.
We derived the following intrinsic (b-y)0 values:
for the Silicon stars HD 179527 and HD 204815 -37 and -24, resp.,
for the Hg Mn star HD 178065 -42,
for the He wk star HD 212454 -70 and
for the He str star HD 209339 -117.
RNS HD
17470 63312 -16 -2 6
18200 66068 -8 4 -6
18950 68457 -2 -7 -3
18990 68542 -4 8 24
19050 68703 -3 13 -6
19060 68725 -16 -1 4
19260 69682 -8 8 0
19550 70826 13 0 -7
19750 71534 4 -9 -15
19850 71866 10 -20 -15
19950 72208 6 0 -3
CP night RNS
HD magV
b-y m.e.
m1 m.e.
c1 m.e.
m.e.
Spt. 1 1 15290? 56152 7.0 25 4 189 6 1063 7 -1 3 A1-A2
1 1 17080 62257 7.6 78 2 222 1 1001 9 5 1 A4-A9
1 1 17470? 63312 7.1 86 4 222 6 948 6 4 7 A2-
1 4 18200 66068 7.0 202 1 228 3 686 4 5 1 A2-F3
1 4 18580* 67317 7.9 171 9 247 6 710 2 6 4 A2-F2
1 1 18950? 68457 6.5 123 1 180 4 1026 3 0 1 A7-
1 4 18990 68542 7.6 268 6 265 3 645 5 -2 4 F3-F7 Sr
1 1 19050? 68703 6.4 177 2 208 4 819 2 4 2 A8- DD
1 4 19060 68725 6.7 252 7 204 3 706 13 -1 3 F2-F6
1 1 19260? 69682 6.5 185 4 194 5 707 4 -6 5 F0- DD
1 4 19550 70826 7 3 390 0 245 2 634 13 -7 2 A3-F8
1 4 19750 71534 7.0 397 5 260 5 577 2 2 3 F2-F9
2 4 19850* 71866 6.8 4 2 284 5 838 10 60 4 A1 EuSrSi
3 4 19950? 72208 6.8 -18 2 131 5 893 8 2 9 B9 MnHg
1 4 19970 72280 7.6 -1 4 185 2 1043 12 12 6 A9-F1
1 4 20170 72792 7.6 216 12 240 3 698 9 0 3 F0 DD
1 1 20220? 72942 7.5 68 2 204 3 1041 11 -12 9 A2-
1 1 20450 73618 7.3 93 3 234 2 970 14 1 3 A3-F0
1 1 20460 73619 7.5 133 4 238 2 829 13 0 7 A3-F2
1 5 20480 73666 6.6 -8 1 174 0 1097 0 1 1 A1-
1 5 21540 76461 6.9 158 3 245 3 753 5 4 1 A5-F3
3 5 21860* 77350 5.5 -23 2 133 2 1012 2 1 1 B9 SrCrHg
1 5 22010 77745 6.9 142 6 245 3 818 1 5 1 A4-F3
1 5 22160* 78209 4.5 160 3 236 1 770 0 0 1 A2-F3
3 5 22170* 78316 5.3 -35 2 112 2 583 16 1 1 B8 MnHg
1 5 22190* 78362 4.6 213 0 244 2 720 1 0 2 A5-F6
1 5 22420? 79066 6.3 202 6 167 4 609 10 -16 1 A9- DD
4 5 22480* 79158 5.3 -63 4 128 5 575 2 31 3 B9 Hewk
? 5 22540? 79439 4.8 121 3 200 2 897 5 -2 1 A6
4 6 22550? 79469 3.9 -35 2 139 1 969 5 -2 0 A0 Hewk
1 6 23320 82030 6.9 147 6 239 6 784 7 -6 7 A0-
1 6 23370 82191 6.6 42 3 191 1 989 6 3 1 A1-F0
1 6 23930 83886 6.5 50 2 206 2 1015 4 3 1 A3-
1 6 24280? 85040 6.1 152 9 210 4 923 1 3 4 A7-
? 6 24410? 85504 6.0 -22 0 134 4 1043 4 3 0 A1
2 6 24690? 86274 6.6 -29 6 124 9 1029 3 6 2 A0 Si
1 6 24750 86516 6.6 109 1 224 6 871 4 -1 2 A2-
1 6 24820 86902 7.2 166 5 236 16 741 18 -3 7 A0-
1 6 25190? 88022 6.7 347 7 188 9 772 3 -1 3 A2-F
3 7 25790* 89822 4.9 -29 1 147 1 955 2 6 1 A0 HgSiSr
2 7 25890* 90044 6.0 -70 5 223 10 911 24 65 4 B9 SiCrSr
2 7 26010* 90569 6.0 -44 6 182 1 940 2 36 5 A0 SrCrSi
1 7 26120 90931 6.9 197 1 229 1 704 2 6 1 A8-F3
2 7 26760 92728 5.8 -26 1 149 3 1024 1 4 0 A0 Si
1 7 26790 92769 5.5 104 0 189 2 897 2 1 2 A2-
1 7 27160? 93901 6.6 199 1 201 1 720 8 2 1 A5-
2 7 27230? 94334 4.7 -12 2 148 1 1054 2 3 3 A1 Si
1 7 27280? 94480 6.2 183 2 202 7 887 2 3 1 A5-F3
1 7 27440 95256 6.4 82 2 249 1 959 5 10 2 A1-
1 3 27470? 95310 5.1 140 1 188 1 1003 2 2 1 A7-
1 8 27840 96528 6.5 119 3 203 9 901 4 -2 0 A3-A7
1 8 28610 99302 7.3 143 9 191 5 804 14 -9 2 A3-F1
1 8 28670* 99620 7.7 106 4 210 2 869 14 0 1 A2-A9
1 3 28740 99859 6.3 79 2 199 2 928 2 -6 1 A3-A9
3 3 29210 101391 6.4 -44 2 110 3 696 4 2 2 B9 HgMn
CP night RNS
HD magV
b-y m.e.
m1 m.e.
c1 m.e.
m.e.
Spt. 1 8 29390 101968 7.9 21 3 189 1 1032 16 10 3 A0-
1 8 29430 102056 7.0 29 1 162 4 1065 10 -1 5 A2-A7
1 3 29730 102942 6.2 192 3 234 4 728 4 6 1 A3-F4
2 8 29830 103498 7.0 -9 3 185 2 1008 3 46 4 A1 CrEuSr
1 3 30150? 104241 7.6 32 3 176 2 1050 5 -4 3 A1
1 2 30250 104513 5.2 158 2 192 2 751 3 1 2 A4-A9
1 8 30550 105601 7.4 165 10 205 17 776 5 4 6 A2-F2
1 2 30930? 106887 5.7 87 1 222 1 929 5 7 3 A3-F1
1 8 31000? 107131 6.5 99 5 189 3 951 1 2 2 A3-A7
1 8 31030* 107168 6.3 97 2 249 3 929 13 18 2 A6-F1
1 2 31080? 107276 6.7 110 8 200 5 907 11 1 3 A3-A7
1 8 31210? 107655 6.2 1 1 168 5 1061 2 5 1 A1-
1 2 31320? 107966 5.2 54 2 174 6 1111 3 6 2 A2-A6
2 9 33450* 115708 7.8 164 3 194 2 766 6 0 4 A3 SrEu
4 9 33470 115735 5.2 -33 1 145 0 942 0 2 2 Hewk Si
1 9 33550 116235 5.9 52 1 206 2 980 3 16 2 A2-A8
1 9 33560 116303 6.4 160 1 178 2 848 3 -3 2 A5-A9
1 9 33610 116542 7.1 130 2 227 1 866 20 9 1 A3-
1 9 33660* 116657 4.0 60 1 234 1 930 2 10 1 A1-A7
? 9 33850 117361 6.4 254 0 176 2 599 3 -6 2 F1 Sr
2 9 34020* 118022 4.9 -14 6 230 2 942 10 51 0 A2 CrEuSr
2 9 34080 
118214 5.6 -9 3 158 2 1007 2 3 1 A0 Si
? 9 34270? 118623 4.8 153 1 175 1 906 5 1 1 A8
1 9 34380 119082 7.4 146 1 232 3 757 7 8 4 A3-F0
2 9 34410* 119213 6.3 36 3 248 8 864 7 26 2 A3 SrCr
? 9 34540? 119765 6.0 -3 3 177 4 1039 3 1 2 A1
2 9 34660* 120198 5.7 -52 0 204 0 915 0 38 0 A0 EuCr
1 10 49580 177983 7.3 248 1 240 0 741 3 2 3 A5-F2 DD
3 10 49620 178065 6.6 70 2 63 6 726 1 -13 4 B9 HgMn
1 10 49630 178265 7.1 154 1 215 6 764 2 3 4 F0-F3
1 10 49650 178327 7.9 196 2 221 2 709 8 -4 2 A6-F5
1 10 49690 178661 7.9 146 3 214 3 782 7 -2 1 A3-F0
1 10 49730 178875 7.8 189 0 213 1 851 6 3 5 A8-F3
1 10 49770 179143 6.8 219 7 254 14 728 15 1 1 A4-F5
? 10 49810? 179367 7.4 116 1 233 0 858 5 1 1 A5
1 10 49850? 179461 7.8 186 5 223 3 730 5 -1 2 A3-F0 DD
2 10 49860* 179527 6.0 3 1 117 1 793 6 26 0 B9 SI
2 11 54660? 196133 6.7 5 1 179 3 1021 1 5 0 A1 SiSr
2 11 54690* 196178 5.8 -74 0 142 2 475 3 35 1 B8 Si
1 11 54700 196240 8.0 93 3 216 1 1091 13 7 2 A4-F0
1 11 54730? 196362 6.4 82 6 197 3 1093 2 2 1 A2-A7
1 11 54740 196425 7.9 121 5 249 5 979 3 17 3 A7-F2
1 11 54790? 196524 3.6 286 1 177 0 540 1 -11 2 F5 Sr
1 11 54820? 196544 5.4 18 1 192 3 1013 8 3 5 A2-A5
2 11 54840 196606 6.3 -44 2 127 2 628 1 20 2 B9 Si
1 11 54880 196655 8.0 46 4 186 2 951 1 34 1 A2-
3 11 54920 196821 6.1 -13 0 122 1 1028 1 14 2 B9- (HgMn)
2 13 56860 204131 6.6 0 5 158 5 1098 1 15 4 B9 SiCrSr
1 13 56880 204188 6.1 143 1 201 1 754 1 2 3 A5-F0
1 13 56890 204262 7.9 116 8 238 4 843 12 4 2 A0-
2 13 56920? 204411 5.3 48 3 190 2 1184 1 19 2 A6 Cr
1 13 56940? 204485 5.8 201 2 191 3 645 1 4 4 F0-
1 13 56970 204541 7.5 138 4 232 4 845 1 17 2 A2-F1
1 13 57000 204751 7.9 221 2 224 1 715 8 1 1 A4-F6
2 13 57030 204815 7.2 16 6 139 7 933 4 40 4 A0 Si
CP night RNS
HD magV
b-y m.e.
m1 m.e.
c1 m.e.
m.e.
Spt. 2 13 57070 204905 7.2 -4 1 155 4 1049 0 0 6 A0 Si
1 13 57080 204918 6.8 184 1 228 1 764 1 -3 2 A7-F5
4 14 58240 209339 6.7 119 2 -15 2 6 4 -26 1 Hewk
3 14 58280 209459 5.8 -10 4 119 1 1054 9 1 1 Hg
2 14 58290* 209515 5.6 -17 4 147 1 1016 4 17 2 CrSiMg
1 14 58360 209711 8.0 156 3 222 2 996 5 8 8 A3-
1 14 58400 209845 7.2 79 3 225 1 972 6 15 4 A1-F1
1 14 58430 209920 7.2 147 8 236 1 805 8 9 3 A2-
2 14 58470* 210071 6.4 -42 1 138 2 562 3 18 1 SiCrHg
2 14 58520 210432 7.2 -1 2 237 3 895 3 25 2 CrSiSr
1 14 58660? 211336 4.2 161 0 195 2 764 3 -1 1 A7-
1 12 58700? 211433 6.9 57 4 215 2 980 15 4 5 A-
1 12 58750 211643 7.1 48 3 219 2 950 2 -3 5 A3-A7
1 12 58780 211785 7.9 126 3 214 5 854 2 -6 4 A2-
1 12 58790? 211797 6.2 156 3 210 5 803 1 2 1 A9-
1 12 58810 211856 8.0 228 5 225 7 695 1 -10 9 F2-
1 12 58840 212079 8.0 139 1 220 5 851 1 -2 3 A0-
4 12 58950 212454 6.2 -43 1 102 2 429 4 1 2 Hewk
1 12 58970 212595 7.4 126 6 234 6 846 3 1 2 A1-A9
1 12 59080 213143 7.8 222 4 249 4 708 9 2 4 A5-
2 12 59100 213232 8.0 63 1 220 3 997 7 17 1 A4 Sr
erroneous