Spectra of resolution λ/Δλ ≡ 2×104 and good S:N ratio are presented in the range containing the 7Li doublet at 6707 Å for 9 main sequence or slightly evolved stars in NGC 752 (age ≡2×109years). The authors investigate the suggested main sequence bimodality using the spectroscopic indications of binarity and high rotational velocity, as well as the

PATT and CAT will consider applications for the use of the Groundbased High Resolution Imaging Laboratory (GHRIL) from September 1988. The applications deadline is May 1st 1988. Users outside the UK/NL/SP community can get access to the GHRIL via collaborations or by applying for "international time". This note contains the minimum amount of

High resolution, high S:N spectra are used to determine the abundances of Fe, Ni, Ca, Al and Si in 25 field dwarfs with -1.2 < [Fe/H] < +0.3. The authors find overabundances for Al, Ca and Si in stars with -1.2 < [Fe/H] < -0.5 and solar [Ni/Fe] over the whole studied range.

The authors have applied to the Sun a method for calibrating, in absolute flux units, Ca II H profiles of late-type stars. After comparing, in the region 3948 - 3882 Å, an LTE synthetic spectrum with the data of the solar flux atlas by Kurucz et al. (1984), they have defined the wavelength ranges where observations agree with computations, based on

The correspondent mass accretion rate values for SS Cygni are deduced from the He II 1640 A emission line equivalent width values in all good available IUE low resolution spectra, using the optically thick boundary-layer model developed by Patterson and Raymond (1985). In the rising and declining phase of an outburst, the mass accretion rate value

A sample of active galaxies and quasars was observed with a photon-counting detector (IPCS) working in time-resolved imaging mode. The observing and data-reduction technique involves taking short-exposure images, selecting from those the sharpest, and adding them up after having corrected them for image motion. Final resolutions of a few tenths of