There is nothing wrong with sighting the moon by means of modern instruments

 

Is it essential that the moon be sighted with the naked eye, or can we use telescopes and modern instruments?.

Praise be to Allaah.

The shar’i evidence indicates that people should not go to
great lengths to sight the moon with these instruments; rather it is
sufficient to sight it with their eyes. But if a person seeks the moon with
them and is certain that he has seen it by means of them after the sun has
set, and he is a Muslim of good character, then I do not know of any reason
why his sighting of the moon should not be followed, because it is still a
visual sighting and is not calculation. End quote. 

Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allaah have mercy on him)