Investigation of the Nova Cyg 1975= the V1500 Cyg at the Crimean Astrophysical Observatory

The Nova V1500 Cyg has been observed with a scanning spectrophotometer from 2.9.75. to 7.10.75; the results obtained are given. The absolute energy distribution in the Nova spectrum within the range from 3300 A to 7500 A is presented. The evolution of the main emission line radiation and of the continuum radiation in three wavelengths is traced. An analysis of the data leads to a conclusion that during the observations the star and the gaseous envelope have contributed comparable portions to the total continuum emission and collisional excitation has been important for hydrogen line emission during two weeks after the Nova maximum. The obtained estimates of the stellar radius are 6.0, 3.4 and 1.1 solar radius for 23rd, 38th and 100th days accordingly after the maximum; these estimates are in agreement with the idea of a slow contraction of a nova remnant but are at variance with a scheme of an origination of a small hot nucleus just after the maximum. The mass of the Nova envelope is about 7x10-5 Sunmass