1. Reduction of Parallax Error in Cesium Magnetometer Surveys Using Laser Alignment Greg Shear Ithaca College Funding provided by: - Ithaca College Physics Dept Ford Research Fund - Ithaca College Summer Faculty Salary - University of Nevada, Las Vegas - Ithaca College Dana Internship

2. The Parallax Error Y-Coord. (m) 11 1 X-Coord. (m) 1 11 Y-Coord. (m) 18 2 X-Coord. (m) 2 18 Drain tiles in OregonRebar stakes in New Mexico

3. The Cesium Magnetometer Survey Method Y-Coord. (m) 18 2 X-Coord. (m) 2 18

4. Breakdown of the Parallax Error ε = (45.0 cm · 98.0 cm) / (177.0 cm – 45.0 cm) = 33.41 cm The only variable we have reasonable control over is h, the distance between the bottom sensor and the ground. θ1 = θ2 tan (θ2) = (H-h) / d tan (θ1) = h / E h / E = (H-h) / d ε = (h·d) / (H-h)

5. Quantifying the Error Metal Stake Compass Possible Sewer Pipe Magnitude of the Earth’s Local Magnetic Field (nT) Distance Along Transect (m)

6. Solution: Laser Alignment Laser Mirror Housing

7. Reduction in Error Distance Along Transect (m) Magnitude of the Earth’sLocal Magnetic Field (nT) Distance Along Transect (m) Magnitude of the Earth’sLocal Magnetic Field (nT)

8. Data Comparison No Laser Northbound No Laser Southbound Laser Southbound Laser Northbound 18.6 18.2 17.8 Position Along the Horizontal Transect (m) With laser Without laser

9. Conclusions ● Parallax problem – 20 cm error in each direction ● Laser alignment reduces this error ● Bodhi and Kevin are unable to reproduce these results ● Other variables currently under investigation

10. Hubcaps

11. White Sands!

12. Valley of Fire!

13. Very Large Array!

14. University of Arizona!

15. Biosphere!

16. Rocky Mountains!