Term ‘Visible Horizon’ in astronomy is defined as:-

• The circle of contact of the earth and the cone of visual rays passing through the meridian of the place.
• The circle of contact of the earth and the cone of visual rays not passing through the meridian of the place.
• The circle of contact of the earth and the cone of visual rays passing through the point of observation.
• The circle of contact of the earth and the cone of visual rays not passing through the point of observation.