Talk about Shani or Sani to a Hindu and the first reaction will be fear and then the mentioning of ill effects and troubles. Shani is dreaded by Hindus, especially by those who believe in astrology. Many people observe an Upvaas or fast - Shanivar Vrat - to avoid the adversities and misfortunes on Shanivar or Saturday.
It is believed that those who have the blessing of Lord Hanuman are protected from the wrath of Shani. Therefore many people make it a point to worship Hanuman at home or in temples. Black is the preferred color on Saturday.
Shani, one of the Navagrahas, is worshipped in numerous temples and there are also temples exclusively dedicated to Sani. Devotees who are observing Shanivar Vrat usually visit Shani shrines. Black colored items like sesame til, sesame oil, black clothes, and black gram whole are offered to Shani. It must be noted here that the color of the idol of Shani is always black in color.
Those devotees who fast on Saturday only take a single meal that too in the evening after prayers. Food prepared usually consists of sesame til or black gram or any other black colored food item. Salt is avoided by many on the day.
Shani is represented as a deity carrying bow and arrows and riding a vulture. Some devotees worship a black iron idol of Sani. Some worship the Peepal Tree and tie thread around its bark. Black colored items like sesame oil and black clothes are also donated on the day.
Shani is so dreaded that many Hindus avoid journeys on Saturday. There are also numerous tales regarding the evil effects of Shani.
But generally it is believed that Lord Hanuman devotees are unharmed by Sani. Legend has it that Lord Hanuman had rescued Shani from Ravana. This happened during the burning of the Lanka episode in the epic Ramayana. Lord Shani had then promised that he would not trouble Lord Hanuman devotees.