Celestron
Celestron specializes in optical astronomy equipment. The high-powered Upclose10X50 Porro binoculars provide bright optics for nighttime sky viewing. The use of Porro internal prisms, named after the inventor, in these binoculars means that the optical quality is the best for your dollar. It also means that the physical design is the classic bulky style and not streamlined or compact. The exit pupil is measured at 5mm, which means that the binocular can focus enough light from the dark sky to provide excellent viewing conditions. The water-resistant body has finger grips and protective rubber coating that makes it practical for humid conditions or beach-side use. This practical pair of binoculars weighs a mere 30 oz.
Pentax
Pentax makes two quality 10X50 binoculars suitable for astronomy purposes. The Pentax PCF Astronomy Binoculars have a durable rubber-coated aluminum die-cast body. Lenses are multi-coated to reduce scattered light reflections that tend to blur celestial bodies. The resulting images are clear and focused. Binoculars are waterproof and durable. Bak-4 technology is incorporated into internal prisms that contribute to a reduction in the overall size and weight of these binoculars. The Pentax DCF SP binoculars are additionally fog-free and have a repellent coating on the lenses.
Garrett Optical
Garrett Optical's Gemini LW astronomical binoculars are lightweight, weighing just 1 lb. 14.5 oz., making them easy to hold. These compact binoculars feature a center knob to slow-focus objects in view. The slow movement provides precision adjustments that are required for viewing the long distances into space. If you wear eyeglasses, this binocular gives 18mm of space at the viewing lens end to give adequate space for your eyewear. All air-to-glass surfaces are completely multi-coated to provide the expected level of contrast and brightness when viewing the night sky. Highly reflective Bak-4 glass is used to craft internal prisms to enhance illumination capability.