Advanced Camera For Surveys (ACS)An optical camera aboard the Hubble Space Telescope that uses CCD detectors to make images. The camera covers twice the area, has twice the sharpness, and is up to 10 times more efficient than the telescopes Wide Field and Planetary Camera 2. The ACS wavelength range spans from ultraviolet to near-infrared light. The cameras sharp eye and broader viewing area allow astronomers to study the life cycles of galaxies in the remotest regions of the universe. Astronauts installed the camera aboard the telescope in March 2002, but the camera experienced an electrical short in 2007 that shut down all but one data channel. During Servicing Mission 4 in 2009, astronauts replaced the failed circuit boards and added a new power supply box to restore power to the camera.AfterglowThe fading fireball of a gamma-ray burst – a sudden burst of gamma rays from deep space – that is observable in less energetic wavelengths, such as X-ray, optical, and radio. After an initial explosion, an expanding gamma-ray burst slows and sweeps up surrounding material, generating the afterglow, which is visible for several weeks or months. The afterglow is usually extremely faint, making it difficult to locate and study.AlloyA mixture of two or more metals. Brass (a mixture of copper and zinc) and bronze (a mixture of copper and tin) are common alloys.Alpha processA process by which lighter elements capture helium nuclei (alpha particles) to form heavier elements. For example, when a carbon nucleus captures an alpha particle, a heavier oxygen nucleus is formed.Created by TechBrick Robotics[email protected]
/ 410.838.8264 / [email protected]TERMDEFINITIONAltitude-azimuthA type of telescope mounting that supports the weight of the telescope and allows it to move in two directions to locate a specific target. One axis of support is vertical (called the altitude) and allows the telescope to move up and down. Theother axis is horizontal (called the azimuth) and allows the telescope to swing in a circle parallel to the ground. This makes it easy to position the telescope: swing it around in a circle and then lift it to the target. However, tracking an object as the Earth turns is more complicated. The telescope needs to be adjusted in both directions while tracking, which requires a computer to control the telescope.AmplifyTo make larger or more powerful; increase. Radio signals are amplified because they are very weak.AmplitudeThe size of a wave from the top of a wave crest to its midpoint.Angular momentumA property that an object, such as a planet revolving around the Sun, possesses by virtue of its rotation or circular motion. An object’s angular momentum cannot change unless some force acts to speed up or slow down its circular motion. This principle, known as conservation of angular momentum, is why an object can indefinitely maintain a circular motion around an axis of revolution or rotation.