| calendar | | a section of the sky that contains a recognizable star pattern |
| tychobrahe | | the apparent path the sun takes across the celestial sphere each year |
| electromagneticspectrum | | all the wavelengths of electromagnetic radiation |
| lightyear | | wrote a book that combined all the ancient knowledge of astronomy he could find |
| year | | the time required for the Earth to orbit the sun once |
| day | | the time required for the Earth to rotate once on it's axis |
| isaacnewton | | a danish astronomer who used several tools to observe the sky |
| romancalendar | | this scientist successfully explained the phases of the moon and the eclipses |
| ptolemy | | a system for organizing time |
| month | | first scientist to explain why celestial objects move as they do |
| leapyear | | our modern calendar was developed from this |
| stonehenge | | a measure of how far east an object is from the point at which the sun appears on the first day of spring |
| altitude | | a telescope that uses curved mirrors to gather and focus light |
| babylon | | a grouping of stones near this place is the earliest recording of astronomical observations |
| reflectingtelescope | | another ancient site that is probably used to make observations of the sky, located near Salisbury, England |
| constellation | | a measure of how far north or south an object is from the celestial equator |
| juliuscaesar | | an instrument that collects electromagnetic radiation from the sky and concentrates it for better observation |
| johanneskepler | | this theory states that the sun is the center of the universe |
| refractingtelescope | | the first scientist to successfully use a telescope to observe the night sky |
| rightascension | | a unit of length equal to the distance that light travels through space in 1 year |
| declination | | a year in which an extra day is added to the calendar |
| copernicus | | the assistant of tycho brahe, who continued brahe's work |
| williamherschel | | this theory stated that the Earth is the center of the universe |
| eclitpic | | discovered Uranus in 1781 |
| galileo | | the angle between an object in the sky and the horizon |
| telescope | | person who created the julian calendar |
| astronomy | | a telescope that uses a set of lenses to gather and focus light |
| nabta | | roughly the amount of time required for the moon to orbit the Earth once |
| aristotle | | this ancient civilization was the heart of the major empire located in present day Iraq |
| ptolemaic | | the study of all physical objects beyond earth |
