(a) Referring to Fig. $12(\mathrm{a}),$ calculate the altitude of the Sun along the meridian on the first day of summer for an observer at a latitude of $42^{\circ}$ north.
FIGURE $12 \quad$ (a) The diurnal path of the Sun across the celestial sphere for an observer at latitude $L$ when the Sun is located at the vernal equinox (March), the summer solstice (June), the autumnal equinox (September), and the winter solstice (December). NCP and SCP designate the north and south celestial poles, respectively. The dots represent the location of the Sun at local noon on the approximate dates indicated.
(b) What is the maximum altitude of the Sun on the first day of winter at the same latitude?