2. Observations, data reduction and photometry
The observational data were collected at the Ostrowik Station of the Warsaw University Observatory on the nights of February 10, February 11, and March 7, 1997. We used a CCD system attached to a 0.6 m telescope (Udalski and Pych, 1992). On the nights of February 10, 1997 and February 11, 1997, we used Cousins I filter for 120 second exposures. On the night of March 7, 1997, we made unfiltered exposures with the integration time of 60 seconds. De-biasing and flat-fielding were done with the procedures available in the IRAF 1 package. The aperture photometry was obtained with the DaophotII program (Stetson, 1987). Since the object was moving, observed fields were different each night. The sum of the light of several bright, apparently constant stars was used as a comparison for each field.
© European Southern Observatory (ESO) 1999
Online publication: March 1, 1999