AstroTech’s ultra-compact telescope is priced for amateurs, yet it rivals larger, more expensive models. By packing in three glass lenses, it focuses red, green and blue light all at a single point. This eliminates the blurry, bluish halo in two-lens amateur scopes, which focus blue light in a different spot than red and green.
Until recently, three-lens systems appeared only in bigger telescopes that cost upward of $2,000 because of the extra labor needed to cut and polish the glass. (Reflecting telescopes, which bend light with mirrors instead of lenses, can focus better, but they are fragile and require complex adjustment.) Now that more companies are in the lens-making business, amateurs can get easy-to-use scopes at easier-to-swallow prices.