Radhastami is not very well known as compared to Sri Krsna Janmastami. The reason is that to understand Srimati Radharani constitutes even more confidential knowledge than to understand Sri Krsna. The following is a very brief understanding of the position of Radharani.
Madana means Cupid. We, in the material world, are all afflicted by the sharp arrows of Cupid. In fact, these arrows of Cupid are the cause of our perpetual bondage in this material world. Cupid reigns supreme in this material world.
But Krsna is called Madana Mohana - The Enchanter of Cupid. In fact, His beauty defeats the beauty of Cupid multiplied a million-fold. Everyone, in the material and spiritual worlds, are directly or indirectly enchanted by Krsna. Therefore, Krsna's position is supreme.
Although Krsna is such an ocean of reservoir of pleasure, there is one person who can completely enchant Krsna. That person is none other than Srimati Radharani. She is so perfect in Her devotional service to Krsna that although Krsna is very sober and completely aloof from all affection, even He cannot help but be attracted to Her. Such is the force of Her devotional service. Within the entire material and spiritual worlds, She alone can completely attract the mind of Krsna. Therefore She is also called Madana-Mohana-Mohini.
Therefore if we try to please Srimati Radharani, then Krsna will be more pleased with us than when we try to please Him directly. We observe this celebration in commemoration of the Appearance of Srimati Radharani so that Krsna will be very much pleased.
