the moon when it is shaped like a crescent, or a time when it is shaped like this

It was dark now and the sliver of a new moon could be seen overhead. 天黑了，一轮新月挂在空中。

The team discovered that the planet is 0.02°C warmer at full moon than at new moon. 工作组发现那颗行星在满月期比新月期时的温度高0.02摄氏度。