Stars become invisible at high altitudes because the Earth becomes very bright compared to the stars. This happens because when you are higher up, you see more of the sunlight reflected by the Earth. This happens because at higher altitudes more of the Earth is visible to you. Thus, your eyes or your cameras cannot distinguish the relatively dim light of the stars. The sky still appears black because there is no atmosphere to make the light scatter and give you feeling of being light outside that you experience on the surface of the Earth. You can see the stars if you are on the night side, you have good cameras, and you set the focal point to the sky.
Stars become invisible at high altitudes because the Earth becomes very bright compared to the stars. This happens because when you are higher up, you see more of the sunlight reflected by the Earth. This happens because at higher altitudes more of the Earth is visible to you. Thus, your eyes or your cameras cannot distinguish the relatively dim light of the stars. The sky still appears black because there is no atmosphere to make the light scatter and give you feeling of being light outside that you experience on the surface of the Earth. You can see the stars if you are on the night side, you have good cameras, and you set the focal point to the sky.
I’ll get to the equinox thing later.