Astron. Astrophys. 331, 187-192 (1998)

2. Observations

The images of V1101 Aql are divided into two data sets. The first one has been acquired on September 10, 1993 with the 0.9m Dutch telescope at La Silla. This run was composed of 71 V and 3 B frames. The second data set was obtained on July 13 and 14, 1996 with the 1.2m telescope of the Asiago Astrophysical Observatory: here, 58 V, 2 B and 2 R frames were collected. Table 1 reports the log of the observations.

Table 1. Journal of the observations reported in this paper

After the standard cleaning procedure for bias and flat field, the frames were processed with DAOPHOT II (Stetson 1987) and ALLSTAR inside MIDAS. Magnitude calibration was performed using the secondary photometric sequence (stars 2, 5, 6 and 7) established by Misselt (1996). The typical error on photometry is 0.02 mag. The internal magnitude differences of the comparison stars were nearly constant within the errors (see Fig. 3a,b): this confirms that only V1101 Aql is responsible for the observed variability. The observation times at mid-exposure were then converted to Heliocentric Julian Days for each magnitude measurement.

A single spectrum of the system was taken on June 9, 1996 with the 1.80m telescope of the Asiago Observatory, equipped with a 300 grooves mm^-1 grating, (wavelength range: 3500-6000 Å), and a slit width of 2" (resolution of 4.3 Å/pixel). This spectrum was extracted and reduced with IRAF, and calibrated in wavelength with a Fe-Ar lamp. Flux calibration was performed with the spectroscopic standard Feige 92.

© European Southern Observatory (ESO) 1998

Online publication: February 4, 1998
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