Soho, Yohkoh, Ulysses and Trace: the Four Solar Missions in Perspective, and Available Resources

Four solar observing spacecraft, now in operation, have obtained and continue to obtain data during the late phase of solar cycle 22 and hopefully most of cycle 23. The data are available for scientific analysis, practically in an unrestricted manner. A large pool of software suited for the processing and to help programming any data analysis is freely available. An almost random list of results that are being obtained with this data is presented as an example of what can be done by analysing the data from these spacecraft, either alone or combining results among them, with ground observatories, or with other spacecraft, such as those that measure particles and fields in interplanetary space or in geospace, to study solar physics or solar-terrestrial relations.