Handout on Constellations PDF

COLLEGE OF SCIENCE Department of Mathematics and Physics Handout on Constellations Constellation is a recognized grouping of stars that forms a distinct pattern in the sky, defined officially by the International Astronomical Union...

COLLEGE OF SCIENCE Department of Mathematics and Physics Handout on Constellations Constellation is a recognized grouping of stars that forms a distinct pattern in the sky, defined officially by the International Astronomical Union (IAU). 88 constellations cover the entire celestial sphere (Ridpath, 2022). Some prominent Constellations: Orion (The Hunter): Visible in the winter sky; notable stars include Betelgeuse (red supergiant) and Rigel (blue supergiant). Scorpius (The Scorpion): Seen in summer; features Antares, a bright red supergiant. Asterism is an informal or smaller recognizable pattern of stars, which may be part of one or more constellations. For example, the Big Dipper is an asterism within the constellation Ursa Major (Kaler, 2021). Some prominent Asterisms: Big Dipper: Part of Ursa Major, helpful for locating Polaris, the North Star. Summer Triangle: Formed by Vega (Lyra), Altair (Aquila), and Deneb (Cygnus). Astrolabe is a historical astronomical instrument used to solve problems related to time and the position of celestial objects. It was widely used in ancient and medieval times by astronomers, navigators, and surveyors. The word "astrolabe" comes from the Greek words astron (star) and lambanein (to take or capture), meaning "star-taker." Components of an Astrolabe: 1. Mater: The main body of the astrolabe, which holds the other components. 2. Rete: A rotating star map with pointers for prominent stars. 3. Plates: Fixed discs marked with celestial coordinates, tailored to specific latitudes. 4. Alidade: A rotating ruler used for sighting objects and measuring their altitude. Constellations | Prepared by MROBalmeo  Uses of an Astrolabe: 1. Celestial Navigation: Determine the altitude of stars or the Sun to ascertain your location on Earth. 2. Timekeeping: Tell time during the day or night based on the positions of celestial bodies. 3. Astronomical Calculations: Solve problems involving the angles, positions, and movement of celestial objects. 4. Teaching Tool: Demonstrates the geometry and movement of the celestial sphere. Constructing an Astrolabe Materials Needed: A printed astrolabe template (available online) Stiff cardboard Scissors A pencil A small brass fastener Steps: 1. Print and cut out the astrolabe template. 2. Glue the template onto the cardboard for durability. 3. Assemble the rete (rotating star map) and attach it to the plate with the brass fastener. 4. Ensure the alidade (sight ruler) is movable. Using the Astrolabe To Tell the Time: 1. Align the alidade with the observed star’s altitude. 2. Rotate the rete until the star is at the correct position on the plate. 3. Read the time from the hour scale. To Locate Stars: 1. Set the date and time using the rete and plate scales. 2. Adjust the alidade to your viewing angle. 3. Identify visible stars from the astrolabe's alignment. Stellarium is a free open-source planetarium app that provides a realistic 3D view of the night sky. It displays stars, constellations, planets, nebulae, and other celestial objects. 1. Installing Stellarium: Download the software from www.stellarium.org. Constellations | Prepared by MROBalmeo  2. Setting Location and Time: Use the location settings to match your observing site and set the desired date/time. 3. Locating Stars: Search for celestial objects by name or browse the sky for visible constellations and stars. 4. Telling Time: Simulate star movements to learn their apparent motion and estimate time based on their positions (Stellarium Team, 2023). References Holmes, A. (2020). The astrolabe: History, construction, and use. Cambridge University Press. Kaler, J. B. (2021). The ever-changing sky: A guide to the celestial sphere. Cambridge University Press. Ridpath, I. (2022). Stars and planets: The complete guide to the night sky. DK Publishing. Stellarium Team. (2023). Stellarium [Computer software]. Retrieved from www.stellarium.org. Prepared by: Mary Rose O. Balmeo CLSU-DMP Constellations | Prepared by MROBalmeo