1. 1 Sun Tracking Stablility Through Imaging Tyson Seto-Mook Institute for Astronomy

2. 2 Overview Coelostat back ground General Project Overview Research and Design Cascade Camera 1k Centroid Equation Centroid routine design Problems encountered Limitations Project status Future goals

3. 3 Coelostat An optical system which is designed to track and reflect a portion of the sky continuously so that the image doesn’t appear to rotate as the earth spins.

4. 4 General Project Overview Problem Coelostat sun tracking Drifts Jitters Solution Take images of reflected beam Calculate centroid of the image Give centroid coordinates

5. 5 Photometrics Cascade Cameras Cascade 1K Low light sensitive 1004x1002 high resolution Cascade 128+ Low Light sensitive 128x128 high speed Availability Programmable control

6. 6 Centroid Equation also known as the center of mass equation, 0,0 1 3 45 65 1 3 3 2 1 1 0 0 0 0 0 0 0 0000 0 0 Y = 2X = 3 1 2 34 5 1 5 4 2 3

7. 7 ABCD Centroid Routine Design Object oriented programming Keep routine independent of program C++ Copy 1d array into a 2d array for easier programming Visual Studio 2008 Simple GUI provided Coelostat driver ABCD

8. 8 Problems Encountered Initial Program Design Overflow when calculating centroid Image intensity values range from 0 to 65535 Possibility of slow calculation Copying 1d array into a 2d array Modified Program Design Divided by factor of 1000 Prevented overflow Threshold Value of 80% of maximum intensity Allowed only important data to be read Read Original 1d array

9. 9 Limitations Works for high contrast images Detects flat images at low contrast Image saturation Placed neutral density filters in front of beam to ensure non-saturated images

10. 10 Current status Base of project completed Working Routine created GUI provided GUI Single image output Streaming images output

11. 11 Possible Future goals Combine simple GUI with centroid program Have visual and numerical outputs Combine Centroid with Coelostat driver Optimize functions Make more efficient Create new functions Rate of change function

12. 12 Acknowledgements The Akamai Internship Program is funded by the Center for Adaptive Optics through its National Science Foundation Science and Technology Center grant (#AST-987683) and by grants to the Akamai Workforce Initiative from the National Science Foundation and Air Force Office of Science Research (both administered by NSF, #AST-0710699) and from the University of Hawaii Akamai Internship Program Institute for Atronomy Mentors Jeff Kuhn JD Armstrong John Messersmith Joe Ritter Scott Seagroves Lynne Raschke Lisa Hunter Lani Lebron

13. 13 Questions? Thank you for listening