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Astron. Astrophys. 344, 632-638 (1999)

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5. Optical variability

The CFHT images have been compared in detail with those obtained in July 1988 with the 3.5 m telescope of the Calar Alto Observatory. The Calar Alto images have a scale of 0[FORMULA]254 pix-1 and were obtained with an RCA CCD with 15 µm pixel size. The filters used were: broad-band I ([FORMULA] Å and [FORMULA] Å at the 10% level), H[FORMULA] ([FORMULA] Å and FWHM = 100 Å) and [S II] ([FORMULA] Å and FWHM = 95 Å). The seeing was [FORMULA] 1". A more detailed description of the images and their reduction is given in Gómez de Castro et al. (1993).

We have not found significant changes in GGD 34 between the two epochs when viewed through the I filter; both morphology and relative intensities remain rather constant. There are however variations between the two [S II] and the two H[FORMULA] frames. The intensity of GGD 34/C relative to this of GGD 34/A has decreased by a factor of 0.25 from 1988 to 1991 in the H[FORMULA] and [S II] images.

No proper motions are detected after comparison of the 1991 images with those obtained in 1988; this is consistent with previous determinations (Ray et al. 1990).

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© European Southern Observatory (ESO) 1999

Online publication: March 18, 1999
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