Do you know the color of Ketu? The invocation of Ketu goes like this: Palash pushpa sankasham (which looks a palash flower i.e. violet and UV type) taraka graha (stars and planets) mastakam (on the head/top)… May be you know that photons of UV rays are very powerful compared to lower frequencies. UV rays have influence on our immune system and skeleton formation. Vitamin D 3 deficiency affects pancreas and diabetes catches you. The nervous system gets jammed in the absence of UV rays and BP goes up. New research on UV rays shows how it creates a feel-good factor in brain. Therefore, Ketu rules over the head region and helps attract sudden wealth and gives out-of-box ideas, and guides you towards moksha (liberation) and spiritual growth. In Jyotish, malefic Ketu is linked to skin related diseases. The medical science links over exposure of UV rays to all types skin problems including skin cancer. That is why; I have been linking Ketu to UV rays.