Аскаплоты советских станций за 1975 год : (оперативно-информационный материал) / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : Кольский филиал АН СССР, 1988.

9 Geophysical Institute, Kola Branch of the USSR Academy of Sciences, 184200 Apatity Murmansk region, USSR). Methods of ascaplotting. The information about auroras for every station according to/1,2/ is encoded in 5 lines divided by vertical lines. One vertical dividing corresponds to a half-an-hour interval centered to the beginning and the middle of each hour (UT). The local geomagnetic midnight is marked by a circle under the ascaplots. Three upper lines show auroral location in the sky. The upper blackened line demonstrates that in a given half-an-hour interval auroras were observed within the scale of the zenith angles from 60° to 80° N. The second blackened line corresponds to auroras in the zenith (from 66® N to 60° S) and the third one shows aurorae in the south (from 60° to 80° S). Occurence of aurorae in the corresponding part of the sky was marked when the aurora was observed during one minute in a given time interval. The aurora location was defined by its bottom edge. Suppose that the height of the lower edge equals to 100 km then we get that all the thacee zenith angle intervale have approximately sufficient extension along the meridian corresponding to 3 degrees of latitude. Thus, ascaplots give information on spatial distribution of auroras in 9-degree-latitude range with its center in the zenith of the station. It should be taken into account that the sensitivity of all-sky cameras is maximum the zenith and it diminishes when the zenith angle increases, i.e. to the edge of the frame. The stars on the films make it possible to judge meteorological conditions in every latitude interval. According to /1,2/ the dot in the middle of the square shows weak cloudiness or cloudiness with rents in the given part of the sky and in the given time-interval. The vertical line denotes complete cloudiness. The tick inside the square of the third line points to bad quality of the aska- film caused by some technical reasons (inaccurate focusing, poor quality of development etc.). The horizontal line denotes absence of observations. To mark moon lightning,which sufficiently reduces the quality of ascafilms, we used an additional designation, i.e. the horizontal line over the ascaplot. The bottom lines of squares carry information about aurora activity. Blackening of the very bottom line means 2 ball auroras. Blackening of two bottom lines refers to 3 ball aurora activity. It should be noted that the activity in ascaplots does not entirely coincide with brightness of forms. The ball of activity also includes such parameters as the type of the form and its life-time within the given half-an-hour interval. Since the compression of the angle range for north and south does not permit similar determinations of peculiarities of auroral forms, the auroral activity in ascaplots was defined only for the zenith region. The series of auroral activity (offered in /9/) which characterizes the connection between the substorm phase and substorm intensity on one hand, and the type of the form, on the other, was taken as a basis. The table for estimating the activity is given in Figure 1. Here the balls of activity are denoted at the bottom, the horizontal lines stand for the types of forms (corresponding to the international classification), as well as brightness of forms (W - weak, M - mean, В - bright). Two circles denote duration of observations, the left circle means that the observation period was more than 15 minutes shorter than that denoted by the right circle. The indices for calculation the balls of activity are given at the top of the Table. Indices 1-3 correspond to the first ball, whereas indices 4-6 and 7-9 correspond to