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Ch 18, Astronomy
Observing the SKy
| Term | Definition |
|---|---|
| astronomy | the study of all physical objects beyond Earth |
| calendar | a system for organizing time; most calendars organixe time within a single unit called a year |
| year | the time required for the Earth to orbit the sun once |
| month | roughly the amount of time required for the moon to orbit the Earth once |
| day | the time required for the Earth to rotate once on its axis |
| leap year | a year in which an extra day is added to the calendar |
| constellation | a section of the sky that contains a recognizable star pattern |
| altitude | the angle between an object in the sky and the horizon |
| right ascension | a measure of how far east an object is form the point at which the sun appears on the first day of spring |
| declination | a measure of how far north or south an object is from the celestial equator |
| celestial equator | imaginary circle created by extending Earth's equator into space |
| ecliptic | the apparent path the sun takes across the celestial sphere each year |
| light year | a unit of length equal to the distance that light travels through space in 1 year |
| telescope | an instrument that collects electromagnetic radiation from the sky and concentrates it for better observation |
| refracting telescope | a telscope that uses a set of lenses to gather and focus light |
| reflecting telescope | a telescope that uses curved mirrors to gather and focus light |
| electromagnetic spectrum | all the wavelengths of electromagnetic radiation |
Created by:
mfender
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