The observations were carried out with the ESO 1.4 m CAT telescope in June and July 1993, and March 1994. In July, the short camera was used in the blue arm, with a resolution of 30000, corresponding to and the [O III] 5007 Å line was observed. In June 1993 and March 1994 the line and neighbouring [N II] 6548, 6583 Å lines were observed, using a resolution of 60000. For the higher resolution is partly offset by the larger thermal broadening. Integration times varied from a few to 30 minutes depending on the line flux. The faintest nebulae could not be observed because they were not visible on the finder due to the brightness of the Moon at both epochs. The slit had a width of and a length of . No flux calibration was performed. The wavelength calibration was done with ThAr spectra, and also checked by observing well-known planetary nebulae as velocity standards.
The data reduction involved flat fielding, summation of the spectrum over the slit and wavelength calibration. The velocity scale was corrected for the Earth's motion to obtain heliocentric velocities. The radial velocity for the [O III] measurements was determined from a first-moment analysis over the line profile. For the measurements of and the [NII] lines (plus in a few cases the nearby HeII 6560.1 Å line) the central velocity between the two peaks was used instead. The uncertainty in the velocities is caused mainly by the method of averaging. The velocity profile is typically wide at half peak intensity. When it is symmetric, the central velocity is easy to define, but often one peak is somewhat stronger than the other or distortions can be caused by a bipolar outflow in combination with an off-centre slit. A different method to obtain velocities is to fit the wings of the line: Spyromilio (1995) finds that this works well, with the wings (defined as line-to-continuum ration less than 10% of the line peak) being more symmetric than the central part of the profile. This method cannot be easily used for our data because one wing is distorted at a low level due to charge-transfer deficiencies of the CCD. The total uncertainty in the velocities was derived by comparing with previous determinations of bright nebulae, for which agreement was found within . Agreement to within is found between the and [O III] measurements (reduced in different ways) for all 13 objects in common, with a mean (systematic) deviation of . This indicates that within the adopted uncertainty, the velocities do not depend on the method of averaging. Higher resolution will not improve this accuracy, which is dominated by the internal motions of the nebulae affecting the moment calculation. In most cases the lines are resolved: detailed analysis of the profiles will be given in Gesicki et al. (1997).
The results are presented in Table 1 (click here). The numbering convention is the one introduced by Acker et al. (1992) which has superseded the previous Perek & Kohoutek (1967) scheme. Velocities are averaged over all available measurements.
Two objects in Table 1 (click here) (004.8-22.7 and 006.8-19.8) have velocities and positions in agreement with the newly discovered Sagittarius Dwarf galaxy and are probably members of this dwarf spheroidal orbiting our Galaxy (Zijlstra & Walsh 1996) at a distance of 25 kpc. A third object in the same direction (003.8-17.1, HB8) also has a large indicated distance but a much different velocity.
|005.2+05.6||M3-12||+17.1||1, 2, 3||6.3|
|353.5-04.9||H1-36||-118.8||1, 2, 3|
|CN2-1||-169.1||1, 2, 3||6.9a|
|358.2+03.6||M3-10||-131.4||1, 2, 3|
|359.1-01.7||M1-29||-41.3||1, 2, 3||3.2|