Observational data on solar activity is a basement for investigation of processes that take place on the Sun and interplanetary space, with data of long-term observations being of special importance. Since 1932 "Catalogues of solar activity" ("Katalogi solnechnoj deyatel'nosti") were published in Central astronomical observatory at Pulkovo (CAO). In these catalogues data on sunspots, faculae, flocculas, protuberances and other solar formations are presented, which were obtained from observations in astronomical observatories of the former USSR. Among these observatories are Mountain astromomical station of CAO, Tashkent astronomical observatory, Astronomical observatory of Irkutsk State university, Astronomical observatory of Kiev State university, Far-Eastern station, Crimean astrophysical observatory, Astronomical observatory of Kharkov State university, Abastumani astrophysical observatory, High-level station of Astrophysical institute of Kazakhstan.
In 2005 in the frame of the project supported by grant of the Russian Fund for Basic Research (RFBR) No.05-07-90107 creation of electronic database began, which will include information contained both in the published "Catalogues" (1932-1979) and in non-published materials of observations (1980-1991). The database will be replenished by materials during all three-year period of the project inplementation. In the final version of the database, data on solar activity will cover the time interval of more than five 11-year cycles.
Section "Data" is divided into subsections corresponding to one of the types of solar formations: sunspots, flocculas, protuberances, etc. Each of the subsections includes data files corresponding to years of observations, with digits in the name of the file marking the number of this year. The subsection also includes an informational file that describes the character and structure of information in the data files.
Subsection "Sunspot groups" is the catalogue of all sunspot groups that were observed in the given year. The extended group number presented in the catalogue consists of four digits of the year and three-digit number of the group in the year. Groups are numerated from beginning of the year, according to time of their crossing the central meridian. A group that disappairs and emerges on the disk again after a break in 4 or more days gets a new number. Groups rising from the limb or emerging on the disk in last days of the year have a regular number of this year, although their can cross the central meridian in January of the next year. The heliographic coordinates consist of latitude and heliographic longitude, which are given for the center of the group (for compact groups) and for two points (for sparse ones). For every day of observation of the group the area of the group, the area of the largest spot (both areas - in millionths of solar hemisphere) and number of spots in the group are presented.
Subsection "Average characteristics of sunspot groups" contains following average parameters for every sunspot group: total area, area of the largest spot and number of spots. The average values, as distinct to the original "Catalogues", are calculated for all days of observation of the group. A day when the group area was maximal is given as a date of the group.
Subsection "Calcium flocculas" includes data about calcium flocculas. Flocculas are numerated in accordance with the same principle as sunspot groups. Areas of flocculas are measured in 1/10000 of solar hemisphere, their brightness - in 3-point scale.
Subsection "H-alpha filaments" contains data on hydrogen filaments. Coordinates are given for the center of the filament, or, if the filament is curved, for several points (in the latter case the filament is described by more than one records with the same number). Intensities are given in 5-point scale
Subsection "Protuberances" contains data in two formates. In catalogues of the first format (up to 1956), areas (in protuberance units) of hydrogen protuberances are presented, summed by 30-degree zones over the solar limb. After digits, which corresponds to areas, letters corresponding to intensity in 5-point scale, followed by digits that describe the form (see format description), can be added. Catalogues of the second format (since 1957) include data on indivitual protuberances for every day: their coordinates, lengths, heights in seconds of arc and brightnesses in 3-point scale (see format description). In both catalogues only protuberances with height not less than 30" are included.
Subsection "Solar Corona" contains data on position angles, bases and brightnesses of solar corona in lines 5303Å and 6374Å observed on Mountain station of CAO. It includes dates of observations, latitudes of centers of radiation, with indication of east or west limbs, the basis of the luminous zone in degrees along the limb of the Sun and brightness according to visual estimates by photographs (0 - intensity of radiation over the limb of the Sun if lower than threshold that can be estimated, 1 - barely perceptible luminescence, 6 - extraordinary bright). Beginning from July 1957 method of observations of the corona and their processing were changed essentially. Therefore, since July 1, 1957 the intensities of the aforementioned coronal lines, measured on distance 40" from the edge of the Sun, are given with 5-degree step in the position angle, which is measured along the limb from the north pole of the Sun through the east. The intensities (both of the line and of the halo) are expressed in millionths of intensity of a continuous spectrum region (with width 1Å) from the solar disk center.
Section "Daily indices" includes files that contain daily values of some indices of solar activity.
Subsection "Wolf numbers" contains daily sunspot numbers for the whole disk of the Sun and for its central zone.
Subsection "Sunspot areas" contains daily total sunspot areas for whole disk of the Sun, for its central zone and the northern and southern parts of the disk. It also includes total daily facula areas. All areas are measured in millionths of solar hemisphere.
Section "Synoptic maps" includes maps of the solar surface built by photoheliograms of Mountain astronomical station of CAO. On the upper axis of each map heliographic longitudes are presented, on the lower axis - dates of passing of longitudes through the central meridian of the Sun, on the vertical axes - heliographic latitudes. The equator is marked by a bold line. The dash line marks projection of the Earth on the Sun. Appearance of sunspot groups corresponds, as a rule, to the moment of their crossing the central meridian. Sunspot cores are filled by black color, penumbras are outlined by solid lines, borders of faculae - by dashed ones. Pores are shown by points.
Other sections contains information about participants of the project and list of publications.