A photoelectric radial-velocity spectrometer has been constructed for the coudé spectrograph of the 1.2-m telescope at the Dominion Astrophysical Observatory. The design of this instrument is discussed, including an innovation which eliminates the problem of "mismatch" for observations of high-velocity stars. Performance of the instrument is discussed, and results are given of a comparison of the spectrometer velocity system with the systems of IAU, LICK, Griffin, and Beavers and Eitter.

The shaping of the nebula is currently one of the outstanding unsolved problems in planetary nebula (PN) research. Several mechanisms have been proposed, most of which require a binary companion. However, direct evidence for a binary companion is lacking in most PNs. We have addressed this problem by obtaining precise radial velocities of seven bright proto-planetary nebulae (PPNs), objects in transition from the asymptotic giant branch to the PN phases of stellar evolution. These have F-G spectral types and have the advantage over PNs of having more and sharper spectral lines, leading to better precision. Our observations were made in two observing intervals, 1991-1995 and 2007-2010, and we have included in our analysis some additional published and unpublished data. Only one of the PPNs, IRAS 22272+5435, shows a long-term variation that might tentatively be attributed to a binary companion, with P > 22 years, and from this, limiting binary parameters are calculated. Selection effects are also discussed.These results set significant restrictions on the range of possible physical and orbital properties of any binary companions: they have periods greater than 25 years or masses of brown dwarfs or super-Jupiters. While not ruling out the binary hypothesis, it seems fair to say that these results do not support it. Subject headings: binaries: general -binaries: spectroscopic -circumstellar matterplanetary nebulae: general -Stars: AGB and post-AGB -Stars: mass-loss collaboration was recently formed with the goal of settling the question of the binarity in PNs and its effect on the shaping of the nebula (PlaN-B; coordinator O. De Marco; http://www.wiyn.org/plan-b/).

We have combined new radial velocities of both components of Capella, obtained at McDonald and Kitt Peak, with those recently published by Batten et al. (1991, PASP, 103, 623), and with interferometric observations, mainly from the Second CHARA Catalog, to derive a new three-dimensional orbit of the Capella system. Our results agree well with those of Hartkopf (1989, AJ, 98, 2275), as well as with those of Batten et al., and yield masses accurate to ±3%. The cooler component, which is the fainter star visually but the more luminous one bolometrically, is the more massive. The mass ratio differs from unity by more than four times its uncertainty, and this lends strong support to the hypothesis that the cool component has begun to consume its core helium. If so, it may be possible to reconcile, qualitatively at least, the orbit's circularity and the stars' rotational velocities with theories of synchronization and circularization, such as that of the Tassouls (1992, ApJ, 395, 259)

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