Observing And Measuring Sunspots In VIS And NIR Regions

Abstract

This study is dedicated for observing and studying sunspots in the visible andnear infrared regions. Visible and near infrared CCD solar imaging system employing5 inch reflecting telescope is used. The obtained visible and near infrared solar imagesduring the period 01-31, January 2007, and their measurements are presented andcompared.Images obtained with the wavelength 850 nm show sunspot groups of sharp contrastcompared with the visible spectrum images. This leads to larger values of solaractivity measurements R and larger daily total sunspots groups areas . According toMcIntosh sunspot classification the frequency of occurrence among the allowed typesof sunspot groups is the same in the both regions. However , the adoption ofwavelength 850 nm is recommended for reliable sunspot observation and calculation .