Term | Definition |
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Eclipse | The total or partial blocking of one celestial body by another |
Emission line | A bright line in a spectrum caused by emission of light. Each chemical element emits and absorbs radiated energy at specific wavelengths. The collection of emission lines in a spectrum corresponds to the chemical elements contained in a celestial object. |
Ephemeris | Tables of data which list the positions of the Sun, Moon, planets and other Solar System objects |
Escape velocity | The minimum velocity required for an object to escape the gravity of a massive object. |
Exposure | The process of allowing electromagnetic radiation to fall on light-sensitive materials such as the camera's CCD detector. An exposure is also the image created by the process. A long exposure time is needed in order to obtain an image of dim and distant celestial objects. |
Extrasolar planet | A planet that orbits a star - other than the sun |
Eyepiece |
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