In many Vishnu or Vaishnavism temples, the Navagraham deities are not installed. You may find them in some temples, but in at least 70% of Vishnu temples, you would not.
Is there a specific reason behind this? I am aware that Sri Vaishnavism, Narayanan is considered the ultimate saviour, but is it the only reason for the Navagrahams to lose their place?