This paper presents the results of high speed photometric observations of the cool variable DA white dwarf (DAV) GD 154 obtained with the Whole Earth Telescope. GD 154 is one of the coolest pulsating DA white dwarfs and its study is important for understanding the red edge of the ZZ Ceti instability strip. Its power spectrum is dominated by three

A three-wavelength sun-photometer was designed and built. The attenuation of direct solar light, at wavelengths of 0.38 micrometers , 0.50 micrometers and 1.00 micrometers were measured. Silicon photodiodes and interference filters of 10 nm FWHM were used. Aerosols were characterized by angstrom's turbidity formula in terms of coefficients (alpha)

We obtain the probability distribution for the volume of excursion sets in a three-dimensional Gaussian field, in order to develop the approximation to the cosmic mass function that follows directly from the assumption that the spherical collapse criteria may be applied to field points. We also use this distribution to develop an analytical

BDS 1269 is a visual binary system with a Delta Scuti star as the primary (Mechler, 1974) and a normal early F main sequence secondary BDS 1269B (HD 15164). Careful observations concerning the brighter primary in this system BDS 1269A (HD 15165, VW Ari) have been undertaken since its first finding by Mechler in 1974. Besides, an unpublished 8 night

The numerical solution of the idealized, but self-consistent, LTE atmosphere problem posed by the authors has been used to introduce the effect of multiple scattering on the temperature gradient, the spectral distribution of the observed flux and the intensity discontinuities. In the theoretical consideration of the problem, the nature of

We have analyzed high spatial and spectral resolution Hα emission-line TAURUS data on two nearby giant H II regions, NGC 604 and NGC 588. Previous work shows that while NGC 604 is a relatively young system whose emission line kinematics is due to a combination of gravity and stellar wind-blown shells, NGC 588 seems more evolved, with its ionized