La fecha 11-Ozomatli es de gran importancia entre las inscripciones calendáricas en la fachada del Templo Serpiente Emplumada Xochicalco. Yo argumenté 1995 el capítulo „Astronomía Xochicalco” libro “La acropolis Xochicalco”, que esta debía marcar principio y fi n ciclo 5200 años sistema En 2020, decir 25 después, al tratar resolver algunos enigmas Cuenta Larga Venus Códice Dresde, particular ex...

The visibility of stars, planets, diffraction coronas, halos, and rainbows during the partial and total phases of a solar eclipse is studied. The limiting magnitude during various stages of the partial phase is presented. The sky radiance during totality with respect to noneclipse conditions is revisited and found to be typically 1/4000. The corresponding limiting magnitude is +3.5. At totality...

Because of the distortions of geometrical optics, .image curves< and, the outlines of the objects that generate them need not have the same topology. New image loops appear when the object curve touches the caustic of the family of (imaginary) rays emitted by the observing eye. Such disruption may be elliptic (loop born from an isolated point) or hyperbolic (loop pinched off from an already exi...

Orbital solutions for binary or multiple stellar systems that combine astrometry (e.g., position angles and angular separations) with spectroscopy (radial velocities) have important advantages over astrometric-only or spectroscopic-only solutions. In many cases they allow the determination of the absolute masses of the components, as well as the distance. Yet, these kinds of combined solutions ...