Why did king henry vii of england commission an exploration to find a "northwest passage" 1497?

King Henry VII of England commissioned an exploration so that a northwest passage is found towards the Orient because the Ottomans had captured Constantinople which was of great importance trade wise and also the waters in the eastern part of the Mediterranean became very dangerous for sale. Because the English king did not wanted to pay huge commissions to the Ottomans so that English boats can pass by freely and safely, he wanted a new route to be found so that the trade can go on freely and by English terms, not someone else's.

honestly i really it keep confusion down on some sides

a. the astrolabe could determine the correct latitudinal location of the ship