astro
Class Seeing

java.lang.Object
  astro.Seeing

public class Seeing
extends Object

A class providing some essential seeing properties.

Nested Class Summary

static class

Seeing.Motion Test the image motion part.

Field Summary

static double

FMAX For higher frequencies, motions are no longer independant.

Constructor Summary

Seeing()

Method Summary

static double[]

motion(double duration, double seeing, double diameter, double wind, double expose, double freq) Returns the image motion of a certain seeing.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FMAX

public static final double FMAX

For higher frequencies, motions are no longer independant.

See Also:

Constant Field Values

Constructor Detail

Seeing

public Seeing()

Method Detail

motion

public static double[] motion(double duration,
                              double seeing,
                              double diameter,
                              double wind,
                              double expose,
                              double freq)

Returns the image motion of a certain seeing. Uses fft to generate a randomized movement using a power spectrum as described in Madec, Conan & Rousset, 1992, in an ESO proceeding.

Parameters:

duration - The duration of the observation in seconds

seeing - The seeing in arcseconds.

diameter - Telescope diameter in meters.

wind - Windspeed in m/s, 10 is a good average.

expose - Exposure time of motion-measuring system or zero for instantaneous measurements.

freq - Maximum frequency of motion-measuring system, maximum FMAX. High values increase array size returned.

Returns:

An array of image motion (arcsec), time steps are 1/2freq.