The point spread functions used for doing photometry on two-dimensional stellar images are described. Analytical functions used for this purpose are discussed and it is indicated that amongst them modified Lorentzian fits the best to the observed stellar profile. The computer programs presently used in crowded stellar region for accurate photometry are also described.
Babu, G. S. D; Shylaja, B. S(D. Reidel Publishing Company, 1982-01)
Based on the observed energy distribution curves of about a hundred Ap stars, the various relationships among their physical parameters: namely, the temperatue, colour index, bolometric correction and bolometric magnitude ...
The H α profile in the spectrum of δ Orionis shows phase-dependent changes, with a period of variation equal to the orbital period fo the binary system. The profile shape changes from a normal absorption profile at zero ...
Mallik, D. C. V(Astronomical Society of Australia, 1991)
The review describes some of the progress made in observations and their interpretation, particularly in the context of the evolution of the nebulae and the central stars. It includes a discussion on the improved determinations ...
