Take a 10minute walk from Manu temple in old manali to reach the disco valley (landmark: Last Stop Cafe) Pick your place among River Rocks and lie down facing the beautiful sky/mountains P.S at this point, you won’t be getting any Network. So plan accordingly.
Lonely place... In old Manali It's got its name after some Israelis used to go there for music jam and fun time. Now a days it's famous for stargazing when it's clear sky.