... 2015 - 2016 . ... Eugene Higgins Professor of Astrophysics, Princeton University . ... December 8, 2015 . ... November 10, 2015 . ... University of the Sciences in Philadelphia author . ... Amateur Astronomer . ... 2014 - 2015 . ... June 9, 2015 . ... Digital Planetarium and the 2012 Transit of Venus from Hawaii . 2013 - 2014 . ... International Occultation Timing Association . ... 2012 - 2013 . ... 2011 - 2012 . ... Princeton University . ... Amateur Astronomers Association of Princeton, Inc., ...

... A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. ... The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program. he introduction of artificial light has caused an unprecedented disruption to the nighttime environment over large areas of the Earth. ... Data processing...

... All the galaxies are divided into 4 groups depending on the environment type; every subsample contains more than 10 galaxies. ... An effect of environments is seen both for the nuclei and for the bulges: if we consider the clusters (Virgo and Ursa Ma jor) and group centers as dense environments and the field and group periphery as sparse environments, then in the dense environments the stellar populations of S0s are in average older by 4­5 Gyr than in the sparse ones. ...

... 337, 275­292 (2002) The correlation of line strength with luminosity and redshift from composite quasi-stellar object spectra S. M. Croom,1 K. Rhook,1 E. A. Corbett,1 B. J. Boyle,1 H. Netzer,2 N. S. Loaring,3 L ... We measure highly significant Baldwin effects for most broad emission lines (C IV 1549, C III] 1909, Mg II 2798, H ,H ) and show that they are predominantly caused by correlations with luminosity, not redshift. ... The correlations of log W with log(1 + z ) for each line. ...

... GRIN lenses for telecommunication optics applications ? GTC (gradient telecom) lenses. ... GTC lenses are used in different fiber-optic devices: collimators, couplers, isolators and WDM etc . ... 2.Diameter . GTC lenses diameters are 1.0 mm, 1.8 mm, 3.0 mm and 4.0mm. ... 1.0 mm -3.0 mm diam GTC lenses are supplied in 0.22P, 0.23P, 0.25P, 0.27P and 0.29P length. 4.0 mm diam GTC lenses are supplied in 0.11P length. ... GTC . ... 3 scratches with 5mkm max width and 200mkm max length are allowed . ...