Frequency spectra of absolute optical instruments

The absolute frequency of the 87Sr optical clock transition

The absolute frequency of the S0–P0 clock transition of 87Sr has been measured to be 429 228 004 229 873.65 (37) Hz using lattice-confined atoms, where the fractional uncertainty of 8.6 × 10−16 represents one of the most accurate measurements of an atomic transition frequency to date. After a detailed study of systematic effects, which reduced the total systematic uncertainty of the Sr lattice ...

Vision and Optical Instruments

26.1. Physics of the Eye • Explain the image formation by the eye. • Explain why peripheral images lack detail and color. • Define refractive indices. • Analyze the accommodation of the eye for distant and near vision. 26.2. Vision Correction • Identify and discuss common vision defects. • Explain nearsightedness and farsightedness corrections. • Explain laser vision correction. 26.3. Color and...

The Absolute Optical Instrument*

Optical Spectra of Supernovae

The temporal evolution of the optical spectra of various types of supernovae (SNe) is illustrated, in part to aid observers classifying supernova candidates. Type II SNe are defined by the presence of hydrogen, and they exhibit a very wide variety of photometric and spectroscopic properties. Among hydrogen-deficient SNe (Type I), three subclasses are now known: those whose early-time spectra sh...

Computing Absolute and Essential Spectra Using Continuation

A continuation approach to the computation of essential and absolute spectra of reaction-diffusion operators on the real line is presented. The advantage of this approach compared with direct eigenvalue computations for the discretized operator are the efficient and accurate computation of selected parts of the spectrum (typically those near the imaginary axis) and the option to compute nonline...