Day 105 – Star Size and Abundance

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Whew. Finally back after two snow days and then a 3 day weekend and a 2 hour delay today! We are on to the HR diagram today and a quick discussion of relative abundance of stars. The above diagram is one of my favorites. Always interesting to talk about how big a million cubic parsecs would be. The question of the week on xkcd is about stars and grains of sand but with a twist worth thinking about! Click on image below.


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Day 21: Celestial Spheres


Today we got out the celestial spheres and started our discussion of celestial coordinates. Students learned how to describe the position of a star using right ascension and declination. Always impressed with how interested they are and how quickly they catch on. We set the spheres to today’s date and discussed the autumnal equinox this weekend and the sun’s position when it rises, is at solar noon, and when it sets.