Observing And Measuring Sunspots In VIS And NIR Regions
Dr.Mohamed Saleh Ahmed , Layale Yahya Salih
Abstract

This study is dedicated for observing and studying sunspots in the visible and near infrared regions. Visible and near infrared CCD solar imaging system employing 5 inch reflecting telescope is used. The obtained visible and near infrared solar images during the period 01-31, January 2007, and their measurements are presented and compared. Images obtained with the wavelength 850 nm show sunspot groups of sharp contrast compared with the visible spectrum images. This leads to larger values of solar activity measurements R and larger daily total sunspots groups areas . According to McIntosh sunspot classification the frequency of occurrence among the allowed types of sunspot groups is the same in the both regions. However , the adoption of wavelength 850 nm is recommended for reliable sunspot observation and calculation.
Keywords : Sun; Sunspot measurements