What's the use of the energetic stone in Zhu Xian's astrolabe?

There are two kinds of astrolabes, one is a perfect gift (you can record three coordinates, fly directly if you want, and consume one F), and the other is a shopping mall, which can record six coordinates. The meaning of astrolabe is that you don't need to calculate how many flying days you want, but you can keep a record of the places you often go. ) and the astrolabe needs to be recharged before it can be used. The astrolabe charging stone is used to charge the astrolabe at Feixian. The astrolabe cannot be used without energy.