Complex sentence: Since the phase curve of Venus is relatively flat while its distance from the Earth can vary greatly maximum brightness occurs during crescent phase, at phase angle 125 °, when Venus can be as bright as magnitude -4.9.
Split into simpler sentences: Since the phase curve of Venus is relatively flat while its distance from the Earth can varies greatly maximum brightness occurs during crescent phase. At phase angle 125 ° Venus can be as bright as magnitude -4.9.