Method and device for evaluating parameters characterizing atmospheric turbulence
AssigneesCentre National De La Recherche Scientifique, Université CôTe D'Azur, Observatoire De La Cote D'Azur
InventorAziz Ziad
Life of this patent
Estimating the term…
Abstract
A method for characterizing the atmospheric turbulence, includes acquiring images of a celestial object by means of a camera coupled to a small telescope; analyzing the acquired images to determine angle of arrival fluctuations of wavefronts from positions of spots formed by the celestial object in the acquired images; determining variances of the angle of arrival fluctuations; and estimating the Fried parameter from the variances of the angle of arrival fluctuations, by setting an outer scale parameter of the atmospheric turbulence to a fixed median value.
Claims15
A method for characterizing atmospheric turbulence comprising:
- acquiring images (SIM) of a celestial object (PS, CB) by means of a camera (CM) of CCD (Charge-Coupled Device) type, said camera (CM) is coupled to a telescope (T) of Cassegrain type, and a Barlow lens (B) is inserted between the telescope (T) and the camera (CM) to extend the focal length of the telescope T;
- said images (SIM) acquired by the camera (CM) are received and processed by a processing card being (PRC) arranged for:
- analyzing the acquired images to determine a time series of an angle of arrival fluctuations of wavefronts in x and y directions from positions of at least one spot (IPS, P1, P2) formed by the celestial object in the acquired images;
- determining variances of the angle of arrival fluctuations;
- and
- estimating the atmospheric turbulence by determining a Fried parameter (r0), from the variances of the angle of arrival fluctuations, by setting an outer scale parameter (L0) of the atmospheric turbulence to a fixed median value of 20 m plus or minus 10%, wherein the at least one spot is formed by Polaris to which the telescope is rigidly pointed.
A method for characterizing atmospheric turbulence comprising:
- acquiring images of a celestial object by means of a camera coupled to a telescope;
- said images (SIM) acquired by a camera (CM) of CCD (Charge-Coupled Device) type, said camera is couple to a telescope (T) of Cassegrain type, and a Barlow lens (B) is inserted between the telescope (T) and the camera (CM) to extend the focal length of the telescope (T);
- said images (SIM) acquired by the camera (CM) are received and processed by a processing card (PRC) being arranged for:
- analyzing the acquired images to determine a time series of an angle of arrival fluctuations of wavefronts in x and y directions from positions of at least one spot formed by the celestial object in the acquired images;
- determining variances of the angle of arrival fluctuations;
- and
- estimating the atmospheric turbulence by determining a Fried parameter (r0), from the variances of the angle of arrival fluctuations, by setting an outer scale parameter (L0) of the atmospheric turbulence to a fixed median value of 20 m plus or minus 10%, wherein the at least one spot is formed by Polaris to which the telescope is rigidly pointed.
Dependencies are inferred from the claim text.