Here we have my version of Princess Celestia’s and Princess Luna’s parents. Queen Summer Sun and King Night Glider. This is how I picture them.
 
Summer Sun was believed to be born at the dawn of time, and created the sunrise. Her mane is an orange, pink and purple aurora similar to the sun rise.
 
She was a kind ruler and promoted peace and harmony among her subjects. Her cutie mark is half a sun and half moon together with a pair of eyes. She also has a sun symbol over her eye. I based her colour on the G3 pony Sunny Daze.
 
Night Glider was a bold noble King, it was believed he created the stars and constellations. His mane is like a starry galaxy.
 
He was the commander during the Equestrian/ Changeling War, and saved Summer sun’s life in a battle. His cutie mark is a blue ringed planet with cluster of stars and moons. He also has a moon and stars symbol on his face. He is loosley based on the G1 earth pony of the same name.