1. Learning Target: Understand the celestial sphere ASTRONOMY DAY 4

2. ENTRY TASK Read the article on light year and answer the following in your notebook: 1.What is a light Year? 2.Why do we use light years? 3.Define a light year. 4.How fast does light travel in a second? in a year? 5.How far is Sirius? 6.When we see a star far away are we seeing it as it exists today? Explain. 7.Why might this be a challenge for astronomers?

3. AGENDA 1.Light year reading and questions 2.Check answers for log scale and get stamp 3.Stellarium due September 16 4.Earth’s Orbital Motion Notes 5.Constellation Project due date September 22 6.Homework: Motion and position worksheet

4. VOCABULARY: USE TODAY’S NOTES TO DEFINE THE FOLLOWING: 1.Celestial sphere 2.Sidereal day 3.Solar day

5. STELLARIUM We will be using a star program throughout the year called Stellarium You will be given instruction on downloading Stellarium on your computer at home and our first Stellarium Lab. Please if you have any difficulties downloading Stellarium at home let me know and I will make sure you can use my computer. Your first lab is due September 16

6. QUIZ 1.Which is right ascension compared to, longitude or latitude? 2.Which is declination compared to? 3.What is the term for the sphere where stars appear to be on the inner surface surrounding the Earth?