Why are Russian cockpit panels painted in turquoise?
According to Cold War Air Museum:


  ...the color chosen by Soviet designers helps to reduce stress and
  maintain a pilot's effectiveness on long missions.
  
  ... the scientists found out that this color keeps pilots awake and
  not getting tired by the black or grey of a cockpit panel, especially
  under terms and condition of long range flights or under heavy work
  load.


This URL contains a color guide for cockpits.