Newtonian telescope secondary mirror. This design reduces the size and cost of the telescope with a shorter overall telescope tube length (with the corrector extending the focal length in a "telephoto" type layout) combined with a less costly spherical mirror. Commercially produced versions of this design have been noted to be optically compromised due to the difficulty of producing a correctly shaped sub-aperture corrector in a telescope targeted at the inexpensive end of the telescope market. Newtonian telescope The Newtonian telescope, also called the Newtonian reflector or just the Newtonian, is a type of reflecting telescope invented by the English scientist Sir
Vila do Conde than 20 metres) disappear north of the Ave River. Yet, these deposits are irregular, and most comparable sediments are not necessarily found at the same altitude. There are also deformations associated with the last inter-glacial period, that have affected these sedimentary layers, most commonly in the beach of Sampaio, where deposits have been discovered between various altitudes (5 and 9 metres). The municipality is subdivided into the following local government civil parishes, of which Azurara, Árvore and Vila do Conde form the urbanized city of Vila do Conde: Vila do Conde is twinned with: The municipal authorities have promoted a