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Astronomy 101 Planetarium Lab. Instructor: Brian Pohl ConOps: Craig Zdanowicz Gabrielle Scronte. Please do not sit in the front row or the southwest section. Schedule – Every other week We WILL meet the weeks of Fall break and Thanksgiving break! Attendance
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Astronomy 101 Planetarium Lab Instructor: Brian Pohl ConOps: Craig Zdanowicz Gabrielle Scronte Please do not sit in the front row or the southwest section
Schedule – Every other week We WILL meet the weeks of Fall break and Thanksgiving break! Attendance 5 P Labs / 5 Night Labs / 1 Makeup Lab Honor Code Grades Must hand in 10 labs to receive full credit You Night Lab TA collects PLabs and grades them Lab Reports Note: the PLab format is DIFFERENT than Night Lab Due Dates Due Wednesday the week after lab Syllabus
Office Hours • Monday and Tuesdays of non planetarium lab weeks. • 3 pm – 5 pm in Morehead room 403 • East entrance facing the arboretum. • Take the elevator on the right to the fourth floor.
General Purpose of Planetarium Lab • We want you to “delight” in Astronomy • We want you to “Look Up” • The Planetarium is a space-time machine • Simulate measurements we could not make in a short space of time, or from Chapel Hill • To learn to write precisely about something technical and detailed • From a few simple measurements, obtain complex understanding • Foster critical thinking
Planetarium Show The delight in looking up part!
Be a MEMBER: International Dark-Sky Association www.darksky.org
Location HAWAII (14,300 ft) CHILE (8,800 ft)
Space! The current frontier HUBBLE Space Telescope
Other wavelengths of light CRAB NEBULA in Radio and X-RAY
Star Counts Lab • We will observe the sky with and without light pollution, and measure the difference in the amount of stars we can count • Cannot count the whole sky, so we count a part of it, and average the rest! • Place eye at large end of cup, point at a region of sky, and count the stars • We’ll do this five times … each time select a different portion of the sky
Calculations and Lab Report • Calculate the TOTAL number of stars in sky • Dimensions of Cup: L=9cm, D=2cm (write this down) • Total area of sky: A1=2πL2 • Area observed (once) in cup: A2= (1/4)πD2 • TOTAL # Stars = (count) x A1/(5xA2) • Calculate the ratio of stars with and without light pollution • Show all work and equations on a separate page • Study the syllabus for correct report format • Calculate percent error against the total amount of stars in the sky without light pollution (~3000) • Final result: how the sky varies with and without light pollution (the ratio)
A Few Brief Words About:Error Analysis • Error is not a mistake • It is not “human error” • It merely exists • Error is a factor that affect the quality and character of the measured data • Is this a good number? • Is this the ‘right’ number? • Some questions to ask yourself: • What am I measuring or observing? [OBJECT] • How am I measuring? [TECHNIQUE] • With what am I observing? [DEVICE] (note: this CAN be you and that is fine) • Types of error: • Random error: effects that are not consistent from one measurement to another • Systematic error: effects that are generally the same every time you make an observation • How to address error in your lab report: • Where possible be quantitative(but you may not be able to be) • See where error most affects your final result and by how much • How could you correct for this error, now that you know about it? • Most importantly: • Do not be vague, be specific about the origin of a source of error • Do not invent an error, support you choice of error with evidence or argument • Do not stress out, you learn with practice how to better examine error over the course of the semester
Hand Calibration • For next time • In order to measure angles in the Planetarium you will: • measure the lengths of your arm, hand and fingers • Refer to pg. 171 for the instructions • Refer to pg. 175 for a diagram
All Power Points are on my website:http://www.physics.unc.edu/~bpohlVisit office hours or email me if you have questions! bpohl@physics.unc.edu Morehead room 403 Mondays, Tuesdays (week-after-lab) 3 - 5pm