Udaipur Solar Observatory ( USO )

The Sun is the only star which presents its disk for a detailed study of its surface-features. Observations of a wide variety of phenomena occurring on the Sun give us some understanding of similar phenomena which may be occurring on other stars too. Thus our Sun is often called the "Rosetta Stone" in astronomy. The scale sizes of the various phenomena on the Sun range from a few kilometers to several thousand kilometers and time scales range from a few seconds or less to several years. The interplay of strong magnetic and electric fields in high temperatures and densities makes the study of the Sun very fascinating but requires high quality observational data for detailed theoretical interpretation of the various phenomena.  Answer to some of the most fundamental questions in solar physics may be found in the observations of the finest possible solar features, as it is generally known that the modern observational solar astronomy lies on the edge of high resolution frontier. With this prime objective, to achieve high spatial resolution solar observations, the Udaipur Solar Observatory was established in 1975 on an island in the middle of Fatehsagar Lake in Udaipur, after a thorough site survey.
In this atlas, we present sequences of chromospheric photographs of some typical solar phenomena during 1976-84, taken mainly in the H-alpha line of hydrogen, through a 15cm aperture refractor (singlet) in conjunction with a Halle' narrow band H-alpha filter mounted on a 4.5 m solar spar at the Udaipur Solar Observatory. The solar photographs are grouped to present characteristics of solar flares, mass ejection, filament activation etc. Each sequence has been provided with a brief description highlighting important aspects of the event. Also each section of photographs is preceded by a general introduction. The purpose of the photographic atlas is essentially to apprise new entrants, students and research workers in solar physics, both observational and theoretical, with the variety of intricate phenomena which occur on the Sun.
In this atlas we have not attempted to present all known solar phenomena or activities. Only those photographs (taken at USO, Udaipur) are presented which display typical examples of various solar phenomena. Earlier in 1970, the Lockheed Solar Observatory group had brought out a pictorial atlas of solar filtergrams taken between 1959-68.
We have also included, in tabular form, a list of interesting events observed at USO, for which the data are available.