How are these celestial coordinates similar to longitude and latitude on Earth?
” The system of locating points on the celestial sphere by dec. and RA involves using a system like latitude and longitude except the lines are located on the celestial sphere. Declination is similar to latitude and Right Ascension is similar to longitude. The celestial equator, 0 dec, corresponds to the Earth’s equator. The lines running parallel to it are like lines of latitude, marked + (between NCP and the celestial equator) and – (between celestial equator and SCP) instead of North and South. The lines of Right Ascension extend from North Pole to South Pole and are divided into 24 hours of 15 degrees each instead of measuring East and West from Greenwich as with longitude. The 0 hour point of RA is the line which runs through the spring equinox. Objects such as stars and galaxies have constant RA/dec addresses just as places on Earth have constant latitude and longtitude, thus making it easy to find them or predict when and where to see them in the sky. 15. “What is special about
