Convenient and helpful device to improve focus of camera tube on Sol’Ex spectrohelioscope
3D-printed Bahnitov mask designed for 30mm guide scopes – purchased from ebay for £6.

Astronomy observatory in Staffordshire, England.
Astronomy observatory in Staffordshire, England.
3D-printed Bahnitov mask designed for 30mm guide scopes – purchased from ebay for £6.