... A detailed mathematical derivation of the posterior probability distributions of the hardness ratios and the computational metho ds we use to calculate them are described in Appendix A, and a detailed comparison of the effects of priors is described in Appendix B. 2. ... Given pre-specified values of the parameters, source and background counts were generated and then used to construct 95% classical and posterior intervals of each hardness ratio using the metho ds discussed in this article. ...

... Hazy skies usually mean steady skies, and steady air is just what the doctor ordered for observing planets and double stars. Mars is well past opposition and becoming less an item of interest as it shrinks in size, but Jupiter and Saturn are well placed in the early morning August sky. ... Their magnitudes are 4.2 and 6.0. ... It has an easily observed 10.6 magnitude central star. ... Cygnus is also host to a lot of small open star clusters that stand up to inspection under hazy skies. ...

Pro duction of ring-like structure in the co co on of Hercules A Curtis J. Saxton1 and Geoffrey V. Bicknell and Ralph S. Sutherland2 ABSTRACT The radio lobes of the radio galaxy Hercules A contain intriguing ring-like structures concentric with the jet axis. ... The lack of a hot-spot near the edge of the lobe, the low contrast of the radio rings and the appearance of the Eastern jet all suggest a low Mach number M 2 - 5, low density ratio < 10-4 jet. ... Core Jet R1 R2 R3 R4 R5 Fig. ...

Rep ort by the ESA-ESO Working Group on Galactic p opulations, chemistry and dynamics Abstract Between the early 40s, when Baade showed the first evidence for the existence of two distinct stellar populations, and today, with our Galaxy surprising us with new substructures discovered almost on a monthly basis, it is clear that a remarkable progress has been achieved in our understanding of the Galaxy, of its structure and stellar populations, and of its chemical and dynamical signatures. Yet, some questions