... An estimate the rotation period of cometary nuclei is important for understanding and describing the physical processes of the cometary activity. Unfortunately, the measurements of the rotation periods of the comet nucleus depend on the model assumptions and it is one of the main reasons for the scatter of the estimates given in various articles for a given comet. ... Right: the image of the comet 29P/Schwassmann-Wachmann 1 obtained at the 6-m telescope. ...

... December 21, 1997 . ... Advantages are briefly discussed of gaining in spectral resolution, which is accompanied by losses in signal level, as compared with the attempts to improve the accuracy of measurement of line parameters by means of rising the S/N ratio alone with increasing the exposure time. To partially solve the problem of observations of faint objects at the BTA a new design echelle spectrometer is proposed. high resolution spectroscopy . ...