NGC 7243 (Wikipedia)
NGC 7243 (also known as Caldwell 16) is an open cluster and Caldwell object in the constellation Lacerta. It shines at magnitude +6.4. Its celestial coordinates are RA 22h 15.3m , dec +49° 53′. It is located near the naked-eye stars Alpha Lacertae, 4 Lacertae, an A-class double star, and planetary nebula IC 5217. It lies approximately 2,800 light-years away, and is thought to be just over 100 million years old, consisting mainly of white and blue stars.- Cartesian coordinate system (Wikipedia)
In geometry, a Cartesian coordinate system (UK: /kɑːrˈtiːzjən/, US: /kɑːrˈtiːʒən/) in a plane is a coordinate system that specifies each point uniquely by a pair of real numbers called coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, called coordinate lines, coordinate axes or just axes (plural of axis) of the system. The point where they meet is called the origin and has (0, 0) as coordinates.
- Polygon (Wikipedia)
In geometry, a polygon (/ˈpɒlɪɡɒn/) is a plane figure made up of line segments connected to form a closed polygonal chain.