... Spherical aberration, coma, and astigmatism are also easily observed using the star test. ... Off-axis images are complex. ... Fig. ... Diffraction by a circular aperture as a function of defocus for no aberration Airy Disk 1 wave defocus Less than 1 wave defocus Fig. ... Diffraction by a circular aperture as a function of defocus for third-order spherical aberration Paraxial Focus Small distance inside paraxial focus Moderate distance from marginal focus Immediate neighborhood of marginal focus Fig...

... Under certain conditions, like those in the nucleus of a QSO, all atoms can be made to emit light at particular wavelengths. ... If that source is approaching the observer, the wave is squashed up onto itself making the wavelength shorter. ... This is redshift. ... You can see how the section of the QSO spectrum which we observe changes with redshift. ... We then see how far we had to slide the observed spectrum along the scale to make it match and that is the objects redshift. ... The 2QZ team . ...

... Full silvery Moon illuminates terrain. ... Begun a next moon eclipse, when Land barriers a Moon from the Sun and throws its shade on it. ... Drawing 1. ... Drawing 6 Drawing 6 shows a splendid photo of full moon eclipse 18-19 november 1975 during is packed phases doing Dennis de Chikko. ... Eclipse, which will occur 9 november 2003, is a repetition through сарос (cycle of repetitions of eclipses equal 6585 days or 18 years 11 days) full moon eclipse from 28 octobers 1985 with the maximum phase 1,07....

... GCR and SCR are primary cosmic rays. 10-15 years after the discovery of cosmic radiation (1919) there emerged two main avenues of investigation in the physics of cosmic rays (CR): 1) nuclear - elucidation of the origin of elementary particles and nuclear interactions; and 2) astrophysical (space physics) - solution of the problem related to the origin and variations (changes in intensity) of CR. ... Besides, the CR flux in interplanetary space is, strictly speaking, not isotropic. ...