Lens articles
How does doubling the aperture diameter affect a telescope's light-gathering power?
What optical challenge is inherent to refracting telescopes using an objective lens?
Why do reflecting telescopes primarily avoid chromatic aberration?
What is the magnification achieved with an objective focal length of 2000 mm and an eyepiece focal length of 20 mm?
What specific axis adjustment is required to track a celestial object using an aligned Equatorial Mount?
What is often cited as a typical trade-off when choosing a reflector over a refractor telescope?
What causes 'empty magnification' when using a telescope eyepiece?
What optical combination defines a catadioptric or compound telescope system?
What is the primary role of the small, low-magnification finderscope attached to the main telescope tube?
What electronic component relies on external power sources like batteries or AC adapters in a modern telescope setup?
What nickname did the press quickly give the Hubble telescope following its initial, blurry images?
What specific optical defect was identified as the primary flaw in Hubble's imaging?
What mathematically perfect shape was required for Hubble’s primary mirror to bring all light rays to a single focal point?
What was the actual error concerning the shape of the primary mirror's edge?
Roughly what was the magnitude of the error in the mirror's shape deviation?
How did scientists confirm the diagnosis of spherical aberration after initial data review?
What factor in the ground-based testing procedures was a major line of inquiry regarding the error's origin?
Which company was the primary contractor responsible for grinding and polishing the primary mirror?
What was the name of the instrument installed in orbit to correct the spherical aberration?
Which servicing mission in December 1993 installed COSTAR and replaced the older camera?
Which instrument utilized COSTAR externally, requiring the external unit to place corrective mirrors in its light path?