Surya * Ravi * Sun * Bhanu Sun is considered the king in 9 planets. His sign is Leo Simha. Simha or Singha is name for Lion in Hindi or Sanskrit. Sun is the most powerful planet.  
He is the natural ruler of fifth house in kala purusha chart. 5 = Leo or fifth house.
Sun get exalted in Aries or Mars sign. Mars is his commander. In addition natural friend of him. His mooltrikona is Leo.
Sun gets dig bala or directional strength in tenth house of a chart.
Sun represents Father and Career of a native. Sun also represents government.
Sun is a mild malefic. Sun gives improved results after 21st birthday for a native.
Surya-Sun Sankranti-Transit Date-Calendar

January 14 Makar Sankranti मकर संक्राति

February 13 Kumbh Sankranti कुम्भ संक्राति

March 15 Meena Sankranti मीन संक्राति

April 14 Mesha Sankranti मेश संक्राति

May 15 Vrishabha Sankranti वृषभ संक्राति

June 15 Mithuna Sankranti मिथुन संक्राति

July 16 Karka Sankranti कर्क संक्राति

August 17 Singh Sankranti सिंह संक्राति

September 17 Kanya Sankranti कन्या संक्राति

October 18 Tula Sankranti तुला संक्राति

November 17 Vrishchika Sankranti वृश्चिक संक्राति

December 16 Dhanu Sankranti धनु संक्राति