1. Innovations Foresight Astronomical Seeing The Astro-Imaging Channel Dr. Gaston Baudat Innovations Foresight, LLC 1(c) Innovations Foresight 2015 - Dr. Gaston Baudat

2. Innovations Foresight Seeing 2(c) Innovations Foresight 2015 - Dr. Gaston Baudat Astronomical seeing is the blurring of astronomical objects caused by Earth's atmosphere turbulence and related optical refractive index variations (air density fluctuations). It impacts the intensity (scintillation) and the shape (phase) of the incoming wave front. This presentation will ignore scintillation.

3. Innovations Foresight Wavefront and phase distortion 3(c) Innovations Foresight 2015 - Dr. Gaston Baudat An incoming plane wave is perturbed by the Earth atmosphere turbulent structure leading to phase errors.

4. Innovations Foresight Fluid dynamics 4(c) Innovations Foresight 2015 - Dr. Gaston Baudat The Reynolds’s (O. Reynolds 1883) number Re predicts flow patterns. For air flow with velocity of few km/h and for length scales of 0.1km to 1km Re > 10 6. Therefore the atmosphere is almost always turbulent. Density Velocity Characteristic length Viscosity

5. Innovations Foresight Source of optical turbulence 5(c) Innovations Foresight 2015 - Dr. Gaston Baudat Energy is transferred by a turbulence cascade form the outer scale L 0 to the inner scale l 0 until heat dissipation (friction). Eddies exhibit different air density -> different refraction index

6. Innovations Foresight Phase structure function 6(c) Innovations Foresight 2015 - Dr. Gaston Baudat Some r (25  (-15 

7. Innovations Foresight The Fried’s parameter 7(c) Innovations Foresight 2015 - Dr. Gaston Baudat

8. Innovations Foresight Atmospheric turbulence strength 8(c) Innovations Foresight 2015 - Dr. Gaston Baudat

9. Innovations Foresight Seeing versus diffraction limit 9(c) Innovations Foresight 2015 - Dr. Gaston Baudat FWHM [“]11.522.53 110 / 4.374 / 2.956 / 2.244 / 1.737 / 1.5

10. Innovations Foresight 10(c) Innovations Foresight 2015 - Dr. Gaston Baudat

11. Innovations Foresight 11(c) Innovations Foresight 2015 - Dr. Gaston Baudat Credit Tokovinin

12. Innovations Foresight 12(c) Innovations Foresight 2015 - Dr. Gaston Baudat 300.93 501.5 702.2 1003.1 3009.3

13. Innovations Foresight 13(c) Innovations Foresight 2015 - Dr. Gaston Baudat

14. Innovations Foresight Aberrations and seeing 14(c) Innovations Foresight 2015 - Dr. Gaston Baudat Zernike’s polynomials Type of aberration removed (inclusive) Tilt/tip36% Defocus33% Astigmatism25% Coma (3 rd order)23% Spherical (4 th order)21% Trefoild (3 rd order)19%

15. Innovations Foresight 15(c) Innovations Foresight 2015 - Dr. Gaston Baudat Tilt/tip removed

16. Innovations Foresight Isoplanatic patch 16(c) Innovations Foresight 2015 - Dr. Gaston Baudat

17. Innovations Foresight Effect of the isoplanatic angle on AO 17(c) Innovations Foresight 2015 - Dr. Gaston Baudat AO operation is usually only effective in a very narrow FOV. Credit R. Dekany, Caltec Palomar AO system IR bands: 1200nm, 1600nm, and 2200nm Guide star offset [“] FWHM [“] 00.2 5.50.3 13 0.45 - 0.59 23 0.51 - 0.68

18. Innovations Foresight Temporal behavior of seeing 18(c) Innovations Foresight 2015 - Dr. Gaston Baudat

19. Innovations Foresight Residual tilt/tip and centroid error 19(c) Innovations Foresight 2015 - Dr. Gaston Baudat

20. Innovations Foresight Lucky imaging and seeing 20(c) Innovations Foresight 2015 - Dr. Gaston Baudat

21. Innovations Foresight Lucky imaging and PSF shape 21(c) Innovations Foresight 2015 - Dr. Gaston Baudat Set of 10 short exposure frames (tilt/tip removed):

22. Innovations Foresight Seeing and wavelength 22(c) Innovations Foresight 2015 - Dr. Gaston Baudat

23. Innovations Foresight Limitations of the standard Kolmgorov’s model 23(c) Innovations Foresight 2015 - Dr. Gaston Baudat

24. Innovations Foresight The Von Karman’s (VK) model 24(c) Innovations Foresight 2015 - Dr. Gaston Baudat

25. Innovations Foresight FWHM and the VK’s model 25(c) Innovations Foresight 2015 - Dr. Gaston Baudat

26. Innovations Foresight Finite OST and guide star wander 26(c) Innovations Foresight 2015 - Dr. Gaston Baudat

27. Innovations Foresight Auto-guiding 27(c) Innovations Foresight 2015 - Dr. Gaston Baudat The goal of auto-guiding is to correct for setup tracking errors. Those errors are independent of the seeing effect and are fully correlated across the FOV (unlike seeing). Long term errors: PE, King’ rate, flexure, model, polar alignment, …, require a slow correction rate (10s to minutes). Short term errors: Mount mechanics (gear box), wind burst, vibrations, …, require a faster correction rate (few seconds). Short term corrections may be prone to seeing effects.

28. Innovations Foresight Auto-guiding and seeing 28(c) Innovations Foresight 2015 - Dr. Gaston Baudat SeeingExcellent 0.5” Good 1.0” Average 2.0 ” Bad 3.0” rms error0.13”0.25”0.50”0.75”

29. Innovations Foresight Auto-guiding/AO rates 29(c) Innovations Foresight 2015 - Dr. Gaston Baudat

30. Innovations Foresight M83 with full spectrum guiding (OAG) NIR versus visible auto-guiding 30(c) Innovations Foresight 2015 - Dr. Gaston Baudat30(c) Innovations Foresight 2013 - Dr. Gaston Baudat M83 with NIR guiding (ONAG) Mario Motta’s relay telescope 32” (0.8m) @ f/6 M86 images with STL11000 + AO-L (few Hz)

31. Innovations Foresight Clear skies! Thank you! 31(c) Innovations Foresight 2015 - Dr. Gaston Baudat Innovations Foresight, LLC