The Sunspot Observations Made In 2005

This paper gives the heliographic coordinates for the sunspot groups observed in 2005 and some other results. The photosphere of the Sun is observed on every clear day at the Istanbul University Observatory. A refracting telescope is used for this purpose; the aperture of the objective and focal length are 13cm. and 200cm. respectively. Sunspots and faculae are drawn on a projection disk of a diameter of 25cm. The heliographic coordinates of the sunspot groups are determined by using the Astronomical Almanac for which the Position Angle of the Sun's axis P0, Heliographic Latitude B0) Longitude L0 are calculated for the time that observation was made. Each sunspot group is observed for a single rotation of the Sun and the results obtained during this period, are given in Tables and in Figures. In this paper, columns in Table I give the following (1); Current numbers of the groups; (2) and (3): The mean latitude and longitude of each group respectively; (4) and (5): First and last observations of the groups respectively; (6): Evolution of the groups which are classified according to Mcintosh Sunspot Group Classification (Solar-Geophysical Data, 1984). The first upper case letter in column gives "Modified Zurich Class". The second upper case letter gives the penumbra of the largest spot. The third upper case letter in the column gives the sunspot distribution. The Figures after these letters give the number of umbrae in each group. The sign "?" denotes a group which was observed at the edge of the disk and could not be identified in the Mcintosh Classification. The sign "X" is used to express that the group probably could not be observed on that day, and "-" that no observation was done on that day because of weather conditions or other reasons. In 2005, 131 groups were observed; 2 of them have a latitude of 0°, 55 of them have an average latitude of +10.29° in the North Hemisphere and remaining 76 groups have an average latitude -9.53° in the South Hemisphere. The distribution of the groups according to their latitudes is as follows (see Fig.l). In Table II, number of groups and umbrae are given by decimal numbers for each day; the integer part of these numbers denote the numbers of the groups and the fractional part numbers of umbrae. Letters across these numbers are the abbreviations of the observers' names; the complete names are given at the end of the Table II.Table III and Table TV give the relative Wolf Numbers for the Istanbul University Observatory and the distribution of the groups in types, respectively. Data in Table IV are summarized in Figure 2.