Sentence:  From the brightness of the F component of the solar corona and the brightness of the zodiacal light , an estimate of the particle sizes , concentrations , and spatial distribution can be derived for regions of space near the <WSD>ecliptic</WSD> plane . 
Meaning of the word marked with <WSD> tags:  the great circle representing the apparent annual path of the sun; the plane of the Earth's orbit around the sun; makes an angle of about 23 degrees with the equator