CHOICE Course: Observing and Counting Sunspots

Instructor: Raffaello Braga.

Observing and counting sunspots is one of the most important and simple methods for monitoring the activity of our nearest star. This four weeks course will provide the fundamentals of visually and photographically observing, monitoring, and recording sunspots with the aim of involving participants in the determination of the American Relative Sunspot Number (RA). This is an effective index of the solar photospheric activity used by amateurs and professionals worldwide. It has been recorded by AAVSO since 1944 with the purpose of maintaining a long-running and consistent database for the use of solar researchers worldwide.

The course will focus on several topics: equipment, safety issues, basic concepts about sunspot activity, morphology, classification and evolution, recording and reporting sunspot observations both visually and photographically, using software for measuring sunspot positions, basic concepts on solar white light digital imaging and how it can usefully complement visual observations and sunspot counts. We’ll also see how solar probe images can be helpful for the amateur observer’s work.

The course will consider only white light observations of the Sun. They can be carried out with a very modest telescope and a commercial solar filter and do not require any expensive equipment. Narrowband (e.g. H-alpha) observing and imaging are outside the scope of the course, however these topics can be discussed informally for those interested in this kind of activity.

There are no prerequisites for participating. The course is open to everybody, even to absolute beginners in solar observing. However more experienced observers may be interested to join for discussing in detail some of the topics and for contributing to the course with their own experience.