Horizon Diagram Assignment ALTITUDE Altitude is a measurement in mapping astronomical objects on the celestial sphere (the sky as visible from Earth). Altitude is the angle of the object from the observer's horizon. If an object is on the horizon, its altitude is 0 degrees. If it is at the observer's zenith, its altitude is 90 degrees. To find an object in the sky, two coordinates are needed, its azimuth and its altitude. AZIMUTH Azimuth is a measurement in mapping astronomical objects on the celestial sphere (the sky as visible from Earth). Azimuth is the angle of the object from the observer's north point (projected onto the horizon). If an object is due north, its azimuth is 0 degrees. If it is due east, its azimuth is 90 degrees, etc. To find an object in the sky, two coordinates are needed, its altitude and its azimuth. HORIZON DIAGRAMS A horizon diagram is a paper and pencil sketch of the day or night sky that includes: A horizontal line representing the observer’s horizon The compass direction the observer is facing Celestial objects in relative position Labels identifying celestial objects name, azimuth (Z) and altitude (A) The date, time and place the observation was made Create a template like the following to fill in the details of your horizon diagram: 90° East South West In the template the rows each represent 10° in the sky with the horizon line at zero and the point above your head at 90°. The middle vertical (up and down) line represents the direction you are facing with the side vertical lines representing 90° on either side of it. In the above example due south is the direction being faced so the right line represents due west and the left line is due east. MEASURING OBJECTS IN THE SKY 1 degree- Hold your hand at arm's length, and extend your pinky finger. The width of your pinky finger is about 1.5 degrees. 5 degrees-Hold your hand at arm's length, and extend your middle, ring, and pinky fingers, with the three fingers touching. The width of your three fingers is about 5 degrees. 10 degrees-Hold your hand at arm's length, and make a fist with your thumb tucked over (or under) your other fingers. The width of your fist is about 10 degrees. 20 degrees-Hold your hand at arm's length, and extend your thumb and pinky finger. The distance between the tip of your thumb and the tip of your pinky finger is about 20 degrees. HORIZON DIAGRAM ASSIGNMENT: 1. You must draw 4 Horizon Diagrams. Be sure to include all necessary information including altitude and azimuth. 2. You will draw all diagrams from the same horizon at different days and times: 3. Draw _________ on ___________ at ______________ and ________________ ___________ at ______________ and ________________ 4. Use your four horizon diagrams and analyze your data using the questions below. A) Compare the location/orientation of the constellation that you observed in the same evening. How are these observations different from early in the evening to later in the evening? What action of the Earth accounts for your observation? Explain. (2 marks KU) B) Compare the location/orientation of the constellation that you observed at approximately the same time over several nights (as far apart in date as you can manage). How are these observations different from the earlier dates to the later dates? What action of the Earth accounts for your observation? Explain. (2 marks KU) C) There are often nights when you cannot clearly observe the stars. i. What technologies have we developed to overcome the interference of weather/atmosphere? Give one example. (2 marks App) ii. Sometimes the weather is not what prevents a good view of the stars. What man made effect(s) are there that make some stars difficult to see. Explain. (2 marks App) Category Knowledge & Understanding Mark out of Total /4 Thinking & Investigation /8 Application /4 Communication /8 /24
