Complex sentence: The largest practical lens size in a refracting telescope is around 1 meter, although Alvin G. Clark, who had made the Yerkes 40 inch objective, said a 45 inch (114 cm) would be possible before he passed away.
Split into simpler sentences: The largest practical lens size in a refracting telescope is around 1 meter. Although, Alvin G. Clark, who had made the Yerkes 40 inch objective, said a 45 inch (114 cm) would be possible before he passed away.