Related Clues:

• Big __ Conference: NCAA division that includes Montana
• Where planes fly
• It’s over your head
• Where stars are seen
• What a stargazer looks toward
• It might be fair or threatening
• It can ''cloud'' your view
• It appears blue as a result of Rayleigh scattering
• Weather app background
• Pie in the __
• 'Why is the ___ blue?'
• Planetarium panorama
• Cloud location
• Vapor trail locale
• It's the limit, some say