The GSM a dedicated monitor for wavefront optical

Summary Ø Presentation of the GSM n Principle n Configuration and optical device Ø

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence Presentation of the

The GSM optical device 3 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence GSM campaigns Ø

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence Typical one night

GSM/DIMM comparison Ø Surface layer effect: w GSM was installed at a height of

Effect of the exposure time Ø Linear extrapolation is done to evaluate the differential

L 0, e 0 & q 0 results La Silla (Chile) Aug. 28 -

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence L 0, e

L 0, e 0 & q 0 results Maydanak (Uzbekistan) July 16 -24 1998

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence Data summary 13

Temporal stability of the AOP Ø For an error of 5%, the change time

Conclusion Ø GSM is operational since 2 years Ø 5 campaigns: n La Silla,

Slides: 16

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The GSM: a dedicated monitor for wavefront optical parameter measurements A. Ziad, F. Martin, R. Conan, J. Borgnino. GSM working layout at La Silla (Chile) Sept. 1997 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

Summary Ø Presentation of the GSM n Principle n Configuration and optical device Ø Atmospheric optical parameters (AOP) data n Data of the outer scale L 0, seeing e 0 and isoplanatic angle q 0 measured at different sites over the world: La Silla, Pachon, Paranal (Chile), Oukaïmeden (Morocco) and Maydanak (Uzbekistan) 1 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence Presentation of the GSM Ø GSM is equipped with 4 telescopes : each one measures synchronously the angle of arrival (AA) of the wavefront n n spatial covariance differential variance scintillation spatio-temporal correlation Þ L 0 Þ e 0 Þ q 0 Þ t 0 2 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

The GSM optical device 3 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence GSM campaigns Ø GSM is operational since 2 years and different sites over the world has been visited w La Silla, Pachon, Paranal (Chile) w Oukaïmeden (Morocco) w Maydanak (Uzbekistan) 4 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence Typical one night measurements L 0 med = 45. 3 m e 0 med = 0. 99’’ q 0 med = 1. 7’’ 5 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

GSM/DIMM comparison Ø Surface layer effect: w GSM was installed at a height of 1. 7 m. w DIMM was installed at a height of 5 m. Ø Exposure time effect: w 5 ms for GSM w 10 ms for DIMM 6 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

Effect of the exposure time Ø Linear extrapolation is done to evaluate the differential variance at the origine w sd 2(0 ms) = 2 sd 2(5 ms) - sd 2(10 ms) 7 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

L 0, e 0 & q 0 results La Silla (Chile) Aug. 28 - Sept. 18 1997 L 0 med = 25 m e 0 med = 1. 68’’ q 0 med = 1. 26’’ 8 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence L 0, e 0 & q 0 results Oukaïmeden (Morocco) April 10 -25 1998 L 0 med = 32 m e 0 med = 1. 33’’ q 0 med = 1. 50’’ 9 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

L 0, e 0 & q 0 results Maydanak (Uzbekistan) July 16 -24 1998 L 0 med = 26 m e 0 med = 0. 66’’ q 0 med = 2. 48’’ 10 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence L 0, e 0 & q 0 results Cerro Pachon (Chile) Oct. 1 -10 1998 L 0 med = 27 m e 0 med = 0. 83’’ q 0 med = 2. 82’’ 11 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence L 0, e 0 & q 0 results Paranal (Chile) Nov. 26 - Dec. 21 1998 L 0 med = 22 m e 0 med = 0. 88’’ e 0 DIMM = 0. 87’’ q 0 med = 1. 9’’ 12 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

The EOS/SPIE Symposium on Remote Sensing - Sept. 1999 - Florence Data summary 13 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

Temporal stability of the AOP Ø For an error of 5%, the change time is: w for the outer scale: 1. 6 mn w for the seeing: 9. 2 mn w for the isoplanatic angle: 4. 6 mn 14 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad

Conclusion Ø GSM is operational since 2 years Ø 5 campaigns: n La Silla, Cerro Pachon, Paranal (Chile), Oukaïmden (Morocco) and Maydanak (Uzbekistan). Ø Important databank of the different sites over the world: n Study of the temporal variability of the AOP and their prediction via a modelization to optimize the HAR observations Ø Results on the Web: http: //www-astro. unice. fr/GSM 15 Département d’Astrophysique - Parc Valrose - 06108 NICE Cedex 2 - France A. Ziad