... These Facts and Questions pages mainly tell you how to use the Aberrator-interface and also explain the nature of the aberrations. ... Airy disc: the brightest spot of light when you look at a star in focus. This disc can contain a maximum of 84% of all the light that arrives from a star (perfect refractor telescope). MCT : Maksutov-Cassegrain telescope. A closed-tube mirror-telescope with a secondary obstruction. Less common than the SCT, this telescope uses a corrector (real glass). ...
... Maps of six sources (0420+022, 0420-014, 1308+326, 1345+125, 1803+784, and DA 193) obtained with milliarcsecond resolution are presented and discussed, together with their broadband (122 GHz) spectra obtained on the RATAN600 radio telescope at epochs close to those of the VLBI observations. ... The image (Fig. 5) shows that the source structure at 18 cm is compact, consisting of a VLBI core and two jet components, with the outer component lying 5 mas (30 pc) to the northwest of the core ( = 54 ). ...