One of the major problems using quasars to investigate the Hubble diagram is an uncertainty as to the size of the bolometric correction. Some estimates have suggested that it may be as high as 6 magnitudes. To this end, the authors have compiled data from a wide range of sources, to investigate the behaviour of quasar spectra over the range from

The development of astrophysical observatories in the Canary Islands by the European community is discussed. Consideration is given to principal astronomical expeditions to the Canary Islands; site testing programs in the Islands; and the agreement established between Spain and the other European countries on the use of the facilities. The

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A a part of a general chromospheric modelling programme on late-type dwarfs, the authors searched for the spectroscopic variability in chromospheric lines associated with activity. They considered especially the α Centauri system, a very close binary system composed of a G2 V and K1 V dwarfs in order to compare them to the sun. The authors searched

An analysis of the frequency spectrum of the amplitude modulation of specific l = 1 p modes was carried out. A mean rotational splitting value of 0.74 mHz was obtained for the frequency range 2.4 to 4.0 mHz. The effects of large scale surface phenomena coupled with surface rotation have been detected. The lifetime of the l = 1 modes varies from

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