1. 20 June 2006 Green Bank GBT Performance Dana S. Balser

2. GBT Performance 20 June 2006 Green Bank Telescope Structure Surface Focus Pointing

3. GBT Performance 20 June 2006 Green Bank Pointing Requirements Condon (2003)

4. GBT Performance 20 June 2006 Green Bank Focus Requirements Srikanth (1990) Condon (2003)

5. GBT Performance 20 June 2006 Green Bank Surface Requirements Ruze (1966) Condon (2003)

6. GBT Performance 20 June 2006 Green Bank Repeatable Errors – Pointing Telescope misalignments: Azimuth track tilt Horizontal collimation Elevation axle collimation Encoder offsets Gravity: assume linear elastic structure

7. GBT Performance 20 June 2006 Green Bank Repeatable Errors – Focus Gravity: assume linear elastic structure

8. GBT Performance 20 June 2006 Green Bank Repeatable Errors – Surface Gravity: Homologous design (almost) Photogrammetry (50.3 deg)  Zero-point Finite Element Model (FEM) Best Fit Parabola (BFP) Active Surface: 2004 Panels 2209 Actuators

9. GBT Performance 20 June 2006 Green Bank Point Source Calibrators Condon & Yin (2005) PCALS 4.0: 7108 sources Two-dimensional rms error < 0.2 arcsec 3 mm pointing calibrators

10. GBT Performance 20 June 2006 Green Bank Pointing Model Balser et al. (2002)

11. GBT Performance 20 June 2006 Green Bank Focus Model Axial Focus Ghigo et al. (2001)

12. GBT Performance 20 June 2006 Green Bank Finite Element Model – Gain Elevation Curve K-band (20 GHZ)

13. GBT Performance 20 June 2006 Green Bank Finite Element Model – Sidelobes

14. GBT Performance 20 June 2006 Green Bank Non-repeatable Errors – Thermal

15. GBT Performance 20 June 2006 Green Bank Non-repeatable Errors – Wind

16. GBT Performance 20 June 2006 Green Bank Thermal Pointing and Focus Corrections Constantikes (2003)

17. GBT Performance 20 June 2006 Green Bank Data Collection and Quality Gaussian Fits (Az, El, Focus) Polarization (LCP – RCP) Direction (Forward – Backward) Jack Scan All-sky Observations Single Source Track Up-Down at Night  Gravity NCP Source  Temperature

18. GBT Performance 20 June 2006 Green Bank Thermal Model – Focus Constantikes (2003) TermCoefficientMin-MaxSignificanceParameter M1M1 1.08613.114.3 SR-Pri M2M2 -0.6976.2-4.3 VFA-Pri M3M3 3.98115.662.0 HFA M4M4 -7.3260.9-6.8 BUS V1 M5M5 -0.68812.1-8.3 BUS V2 M6M6 -2.57612.1-31.2 BUS F M7M7 -180.6300.0 Offset M8M8 66.189.743.1 sin term M9M9 196.9490.6110.8 cos term

19. GBT Performance 20 June 2006 Green Bank Thermal Model – Azimuth Constantikes (2003) TermCoefficientMin-MaxSignificanceParameter M1M1 5.58624.022.4 Alidade M2M2 -8.03312.721.3 HFA M3M3 -1.62892.43.8 BUS M4M4 1.36832.02.8 VFA M5M5 3.41240.0 CA, d(0,0) M6M6 1.32230.71.0 NPAE, b(0,1) M7M7 3.51520.93.0 IA, d(0,1) M8M8 -2.49601.94.8 AW, b(1,1) M9M9 -1.33601.82.5 AN, a(1,1)

20. GBT Performance 20 June 2006 Green Bank Thermal Model – Elevation Constantikes (2003) TermCoefficientMin-MaxSignificanceParameter M1M1 -4.64551.2-5.3 BUS M2M2 1.783015.6-27.8 HFA M3M3 4.44885.926.4 VFA M4M4 -8.44771.6-14.0 Alidade M5M5 62.22180.0+0.000 -IE,d(0,0) M6M6 -55.86240.7-62.792 HZCZ,b(0,1) M7M7 -22.82680.9-38.216 HZSZ,d(0,1) M8M8 2.49602.0+2.169 -AW,c(1,0) M9M9 -1.33602.0-1.750 AN,d(1,0)

21. GBT Performance 20 June 2006 Green Bank Performance – Blind Pointing

22. GBT Performance 20 June 2006 Green Bank Pointing Data Quality – Polarization

23. GBT Performance 20 June 2006 Green Bank Pointing Data Quality – Direction

24. GBT Performance 20 June 2006 Green Bank Cross-Elevation Uncertainty

25. GBT Performance 20 June 2006 Green Bank Elevation Uncertainty

26. GBT Performance 20 June 2006 Green Bank Focus Data Quality – Polarization

27. GBT Performance 20 June 2006 Green Bank Focus Uncertainty

28. GBT Performance 20 June 2006 Green Bank Performance – Offset Pointing

29. GBT Performance 20 June 2006 Green Bank Offset Pointing Uncertainty

30. GBT Performance 20 June 2006 Green Bank Offset Focus Uncertainty

31. GBT Performance 20 June 2006 Green Bank Performance – Tracking Half-power in AzimuthHalf-power in Elevation

32. GBT Performance 20 June 2006 Green Bank Power Spectrum Servo resonance 0.28 Hz

33. GBT Performance 20 June 2006 Green Bank Servo Error

34. GBT Performance 20 June 2006 Green Bank Performance – Summary Benign Conditions: (1) Exclude 10:00  18:00 (2) Wind < 3.0 m/s Blind Pointing: (1 point/focus) Offset Pointing: (90 min) Continuous Tracking: (30 min)

35. GBT Performance 20 June 2006 Green Bank Surface Improvements – Holography Traditional Holography (Phase Coherent Holography) Out-of-Focus Holography (Phase Retrieval Holography) Maddalena Nikolic et al. (2006)

36. GBT Performance 20 June 2006 Green Bank Zernike Polynomials – Radial Terms Zernike (1934) Wyant & Creath (1992)

37. GBT Performance 20 June 2006 Green Bank Zernike Polynomials – Images Wyant & Creath (1992)

38. GBT Performance 20 June 2006 Green Bank OOF Holography – Gravity Nikolic et al. (2006)

39. GBT Performance 20 June 2006 Green Bank Gain-Elevation Curve Nikolic et al. (2006) FEM only FEM + OOF

40. GBT Performance 20 June 2006 Green Bank OOF Holography – Thermal Effects