Homestar Planetarium Disc - Aurora Borealis & Scenic Disc Taiga Dew Shield Aperture ratio: f/10

Aperture ratio: f/10

the play is largely eliminated - you don't have to readjust even when there are large temperature differences

so there will be no vignetting with fast telescopes

Legs Tube Diameter: 18

Homestar Planetarium Disc - Aurora Borealis & Scenic Disc Taiga Dew Shield Aperture ratio: f/10This optional additional disc adds a new dimension to your Homestar Planetarium and features a stunning panoramic view of Aurora Borealis appearing in the night sky. Aurora Borealis is commonly visible in the northern artic skies as radiation from the Sun hits our atmosphere and creates a magical plasma effect. This disc is designed for use with the Homestar Planetarium.