2. Observations

V 839 Oph was included in our observing program in 1989 and since then the system was observed for 9 nights in 1989, 8 nights in 1990, 7 nights in 1991, 2 nights in 1992, 2 nights in 1993 and 3 nights in 1994. A journal of the observations is given in Table 1 (click here). Differential observations were obtained with a 30 cm Maksutov telescope of Ankara University Observatory equipped with an photometer head which is used with a Hamamatsu R1414 photomultiplier tube. Before Sept 29, 1991, the differential observation were made by using an photomultiplier attached to the Maksutov telescope. The filters used are in close agreement with the standard UBV bands.

The same comparison star and check star were chosen as Binnendijk (1960). All differential observations were reduced outside the atmosphere using the extinction coefficients calculated in the usual way, and heliocentric corrections were made for all the observations. The differential measurements in the sense variable minus comparison are listed in Table 2 (click here) (available in electronic form). The light curves formed by these observations in different years are shown in Fig. 1 (click here) together with the colour curves. No significant reddening in the B-V and U-B colour curves is detectable. Although the seasonal observations were obtained in short time intervals, the scatter in the observations, particularly in the U filter, was found larger than expected. This is due partly to the use of an old photometer (between 1989 and 1991) and to occasional bad weather conditions. The observed differences of the check star relative to the comparison star are given in Table 3 (click here). These uncertainties are much smaller in the 1992-1994 observations, which were secured with the new photometer head.

The phases were calculated by using new linear light elements, explained in the following section.

  
Figure 1: The light curves and colours of V 839 Oph in between 1989 and 1994

 

Year HJD Num. of Observer^(a) Obs.

1989 7656 24 SD

7683 4 ZM

7689 5 ZM

7701 15 FFO

7703 35 ZM

7704 20 GK

7717 20 HD

7734 44 FFO

7736 11 BG

1990 8072 24 FFO

8073 13 GK

8084 41 GK

8087 4 GK

8089 13 SO

8090 18 SOS

8091 21 SO

8092 24 SOS

1991 8439 32 HD

8440 21 FFO

8442 40 SO

8447 10 SO

8450 47 FFO

8456 44 HD

8467 34 SO

1992 8829 87 ZM

8835 95 ED

1993 9151 99 BG

9159 90 FFO

1994 9515 36 AA

9522 88 HEK

9536 90 KK

 

 

HJD PHASE (2400000+)

47656.3989 0.503 0.047 0.256 0.250 0.208 -0.006

47656.4057 0.536 0.070 0.215 0.359 0.145 0.144

47656.4175 0.565 -0.015 0.079 0.222 0.094 0.143

47656.4246 0.582 -0.013 0.008 0.131 0.021 0.123

47656.4301 0.596 -0.115 -0.025 0.031 0.089 0.056

47656.4403 0.621 -0.251 -0.141 -0.005 0.109 0.136

47656.4459 0.635 -0.254 -0.182 -0.078 0.073 0.104

47656.4520 0.649 -0.328 -0.201 -0.133 0.127 0.068

47656.4581 0.664 -0.344 -0.255 -0.147 0.089 0.108

47656.4620 0.674 -0.406 -0.210 -0.151 0.196 0.060

47656.4678 0.688 -0.447 -0.294 -0.187 0.153 0.107

47656.4731 0.701 -0.431 -0.297 -0.197 0.134 0.099

47656.4784 0.714 -0.430 -0.333 -0.249 0.098 0.084

47656.4833 0.726 -0.440 -0.333 -0.261 0.107 0.072

47656.4881 0.738 -0.416 -0.331 -0.267 0.086 0.064

47656.4930 0.750 -0.495 -0.373 -0.317 0.123 0.056

47656.5020 0.772 -0.482 -0.337 -0.240 0.145 0.097

47656.5064 0.782 -0.466 -0.341 -0.309 0.125 0.031

47656.5182 0.811 -0.445 -0.340 -0.327 0.105 0.013

47656.5234 0.824 -0.470 -0.338 -0.216 0.132 0.123

47656.5285 0.836 -0.416 -0.289 -0.195 0.127 0.094

47656.5334 0.848 -0.445 -0.325 -0.209 0.121 0.116

47656.5377 0.859 -0.371 -0.279 -0.224 0.092 0.055

47656.5418 0.869 -0.396 -0.247 -0.141 0.149 0.106

47683.3307 0.366 -0.326 -0.234 -0.095 0.092 0.139

47683.3350 0.377 -0.336 -0.213 -0.113 0.123 0.100

.... .... .... .... .... .... ....

 

 

Check Star n V n B n U Observation Time

1989 18 0.0349 18 0.1706 17 0.0489

1990 19 0.0456 19 0.0302 19 0.1085

1991 27 0.0419 25 0.0389

1992 39 0.0210 39 0.0233 39 0.0313

1993 36 0.0204 36 0.0176 36 0.0295

1994 55 0.0251 55 0.0202 34 0.0331