1.   An early form of analogue computer, the astrolabe was primarily designed to solve problems of spherical trigonometry to shorten astronomical calculations.

2.   As you can see, we are embarking on another of those astronomical calculations.

3.   After exacting an enormous fee, the magician performed an astronomical calculation.

4.   But there are arguments over whether telescopes and astronomical calculations can be used.

5.   He thinks North American Muslims should use astronomical calculations to set dates well in advance, the way Jews and Christians do.

6.   Muslims traditionally follow that literally and recognize only actual visual sightings rather than astronomical calculations, so the date is not known in advance.

7.   They however accept astronomical calculations as an indicator.