Mount Graham                                                                        

Since November 2004, site testing campaigns for a monitoring of the vertical distribution of the optical turbulence are on-going at Mount Graham with a Generalized SCIDAR (GS) on the Vatican Advanced Technology Telescope (VATT). Analysis of the optical turbulence will be posted in this Web Page as they happen.

Measurements have been taken with a Generalized SCIDAR (D. Mc Kenna), an optical instrument that measures the scintillation maps produced by binary stars on the pupil of the telescope (at least 1 m size). The optical turbulence vertical distribution (CN2 profiles) is retrieved from the auto-correlation of the scintillation maps. The binary stars have the following properties: a separation θ within the (3" - 14") range;   m1, m2 ≤ 5.8 mag; Delta(m) ≤ 1.5 mag. Wind speed vertical profiles can be retrieved from the cross-correlation of scintillation maps taken with a time lag of typically 20 - 40 msec.

Since May 2005 we are also running the GS in a new modified configuration suitable to obtain a high-vertical resolution (~ 25 m) CN2 profiles in the first 600 m.

Below is the summary of the data analysis:  the nightly astroclimatic parameters (seeing and isoplanatic angle) and composite turbulence profiles.  We hope to progressively achieve a useful database for as many as possible applications. It is, indeed, our wish to support in the best way LGS, GLAO and MCAO programs on-going at LBT. Readers can find some complementary outputs also in scientific publications.

Please read carefully the  Policy for data usage.

Generalized Scidar Runs - All

- 25/11/2004 - 28/11/2004
- 04/12/2004
- 27/04/2005
- 20/5/2005 - 27/5/2005
- 07/12/2005 - 11/12/2005
- 14/12/2005 - 15/12/2005
- 28/05/2007 - 04/06/2007
- 15/10/2007 - 28/10/2007
Next run: 21/2/2008 - 3/3/2008

Summary of reduced generalized SCIDAR data (dome seeing included)

Readers can find here only data completely reduced. Some data require a more sophisticated analysis. We will up-date new results as soon as they will be available.

Nightly seeing and isoplanatic angle statistics:
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A graphical representation of the above nightly statistics:

  Seeing related to all data-sets                                               Isoplanatic angle related to all data-sets                                                

Caption: dashed line: median
for the whole data set;  dotted line: 1st and 3rd quartiles       



Composite Profiles - Inputs for AO Simulations   (LGS/GLAO system)

Standard GS data reduction

Legenda: The three groups of discretized profiles represent the good, typical and bad components of the GL and FA. The atmosphere is divided in 9 vertical slabs i. The boundaries of the vertical slabs are: [-1000,1000,2000,4000,6000,8000,10000,12000,14000,22000] [m].
- The factor Ji is the integral of the CN2 in the slab i. It expresses the turbulent energy in the vertical slab i.
   to convert J to: r0 in [m] at 0.5 microns = 5.07e-9 * J^(-3./5)
 
to convert J to: e0 in ["] at 0.5 microns = 1.99e+7 * J^(3./5)

- In the first column, h* [m] is the average height calculated as: h* = Integral[ hxCn2xdh] / Integral[Cn2xdh]

"Good": The mean of the CN2 profiles associated to a "seeing" within 20% and 30%

"Typical":
The mean of the CN2 profiles associated to a "seeing" within 45% and 55%

"Bad":
The mean of the CN2 profiles associated to a "seeing"  within 70% and 80%

ALL data sets - Average discretized vertical turbulence distribution
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Summer [March-August] - Average discretized vertical turbulence distribution

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Winter  [September-February]
- Average discretized vertical turbulence distribution
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Data reduced and treated by Jeff Stoesz

E.Masciadri, 1/2008