1. Calibration of the LSST Camera Andy Scacco

2. LSST Basics Ground based 8.4m triple mirror design Mountaintop in N. Chile Wide 3.5 degree field survey telescope ~30 Tbits / night of data Dark energy / cosmology

3. LSST Layout

4. Etendue Etendue = FOV * Collecting area Measures the rate of incoming data

5. The point spread function Stars are point sources PSF is image of a point source Combination of atmosphere + telescope aberration Measured by the full width at half maximum (FWHM) PSF of LSST has a 30 micron FWHM

6. Atmospheric Seeing Atmosphere blurs images Instrumental blurring is much less than atmosphere Large ground based telescopes need adaptive optics

7. Camera Design

8. Focal Plane CCD Array We need a 30 micron spot on focal plane CCD wells are 10 x 10 microns LSST has 3.2 Gpixels

9. Laser TEM00 mode Helium-neon / Tunable Gaussian beam Very good for optics analysis

10. Monochromator part 1 Filter / Monochromator Pinhole produces Frauenhofer diffraction Airy diffraction pattern

11. Monochromator part 2 Airy pattern resembles Gaussian Second pinhole cuts off all but the central peak

12. Lens aberrations Lenses aren’t perfect Astigmatism is biggest problem for us

13. Astigmatism Sagittal / tangential rays focus to different locations

14. Camera ZEMAX Design

20. Testing Schematic Reference Photodiode Laser 30 micron spot Photodiode Array Focal Plane

21. My Other Project… Testing a laser sensor system for use in measuring distance very precisely It will be accurate enough to be used to measure the flatness of the focal plane of the LSST

22. Apparatus Laser displacement sensors Optical Flat Precision movable platform

23. Data

24. Data #2

25. Further work Figure out why the correction function differs between the two trials Calculate a best fit sawtooth function to subtract from the data to make it more accurate Use the sensor with the correction function to measure the components of the LSST

26. Acknowledgements David Burke – my excellent mentor Andy Rasmussen – other excellent mentor Steve Rock The DOE, Office of Science SLAC Stanford All my fellow SLAC-ers

27. References http://www.cambridgeincolour.com/tutorials/graphics/airydisk-3D.png http://navj.wz.cz/061116_025307-70_56_19_226.jpg http://www.rp-photonics.com/img/gauss_r.png http://publication.lal.in2p3.fr/2001/web/img344.gif http://laser.physics.sunysb.edu/~wise/wise187/2005/reports/deb/gauss1.gif http://cache.eb.com/eb/image?id=3246&rendTypeId=4

28. References 2 “Large Synoptic Survey Telescope”, Available at http://www.lsst.org (2007 August 9). D. Burke, private communication (2007). “Point Spread Function”, Available at http://en.wikipedia.org (2007 August 6). “Astronomical Seeing”, Available at http://en.wikipedia.org (2007 August 3). “Full Width at Half Maximum”, Available at http://www.noao.edu/image_gallery/text/fwhm.html (2007 August 6). “Gaussian Beam”, Available at http://en.wikipedia.org (2007 July 25). A. Sonnenfeld, private communication (2007). “Airy Disk”, Available at http://scienceworld.wolfram.com/physics/ (2007 July 25). “Astigmatism”, Available at http://en.wikipedia.org/wiki/Astigmatism (2007 July 25). “Aberrations”, Available at http://grus.berkeley.edu/~jrg/Aberrations/ (2007 July 25).