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The Sloan Digital Sky Survey is the largest redshift survey conducted to date, and the principal survey observations have all been conducted on the dedicated SDSS 2.5m and 0.5m telescopes at Apache Point Observatory. While the whole survey has many unique features, this article concentrates on a description of the systems surrounding the dual fibre-input spectrographs that obtain all the survey spectra and that are capable of recording 5,760 individual spectra per night on an industrial, consistent, mass-production basis. It is hoped that the successes and lessons learned will prove instructive for future large spectrographic surveys.
Numerical simulations of star formation have found that a power-law mass function can develop at high masses. In a previous paper, we employed isothermal simulations which created large numbers of sinks over a large range in masses to show that the p
The inversion of a gravitational lens system is, as is well known, plagued by the so-called mass-sheet degeneracy: one can always rescale the density distribution of the lens and add a constant-density mass-sheet such that the, also properly rescaled
Very recently, the LHCb Collaboration reported the observation of several enhancements in the invariant mass spectrum of a $J/psi$ pair between 6.2 and 7.4 GeV. In this work, we propose the dynamical mechanism to mimic the experimental data of a di-$
A fundamental puzzle of our solar systems formation is understanding why the terrestrial bodies including the planets,comets,and asteroids are depleted in $^{16}$O compared to the Sun. The most favored mechanism,the selective photodissociation of CO
The Magellanic clouds are uniquely placed to study the stellar contribution to dust emission. Individual stars can be resolved in these systems even in the mid-infrared, and they are close enough to allow detection of infrared excess caused by dust.W