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CR2RE Pipeline Reference Manual 1.6.7
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Functions | |
| hdrl_parameter * | hdrl_dar_parameter_create (hdrl_value airmass, hdrl_value parang, hdrl_value posang, hdrl_value temp, hdrl_value rhum, hdrl_value pres, cpl_wcs *wcs) |
| Creates DAR parameters object with the values in the header. | |
| cpl_error_code | hdrl_dar_compute (const hdrl_parameter *params, const hdrl_value lambdaRef, const cpl_vector *lambdaIn, cpl_vector *xShift, cpl_vector *yShift, cpl_vector *xShiftErr, cpl_vector *yShiftErr) |
| Correct the pixel coordinates of all pixels of a given pixel table for differential atmospheric refraction (DAR). | |
| hdrl_value | hdrl_dar_owens_saturation_pressure (hdrl_value hvT) |
| Compute the saturation pressure using the Owens calibration. | |
| hdrl_value | hdrl_dar_filippenko_refractive_index (hdrl_value hvL, hdrl_value hvP, hdrl_value hvT, hdrl_value hvF) |
| Compute the refractive index for the given wavelength following Filippenko formulae. This function is called by hdrl_dar_compute(). | |
| cpl_error_code hdrl_dar_compute | ( | const hdrl_parameter * | params, |
| const hdrl_value | lambdaRef, | ||
| const cpl_vector * | lambdaIn, | ||
| cpl_vector * | xShift, | ||
| cpl_vector * | yShift, | ||
| cpl_vector * | xShiftErr, | ||
| cpl_vector * | yShiftErr | ||
| ) |
Correct the pixel coordinates of all pixels of a given pixel table for differential atmospheric refraction (DAR).
| params | In: h_parameter with all of params. in the observation |
| lambdaRef | In: Reference wavelength (in Angstroms) |
| lambdaIn | In: One lambda for each plane (in Angstroms) |
| xShift | Out: Correction for each plane in x-axis (pixels) |
| yShift | Out: Correction for each plane in y-axis (pixels) |
| xShiftErr | Out: Error in correction for each plane in x-axis (pix) |
| yShiftErr | Out: Error in correction for each plane in x-axis (pix) |
Loop that compute the DAR offset for the wavelength difference with respect to the reference wavelength, and storage the shift in the coordinates, taking into account the instrument rotation angle on the sky and the parallactic angle at the time of the observations.
The algorithm from Filippenko (1982, PASP, 94, 715). This only uses the formula from Owens which converts relative humidity to water vapor pressure.
Definition at line 218 of file hdrl_dar.c.
References hdrl_dar_filippenko_refractive_index(), and hdrl_dar_owens_saturation_pressure().
| hdrl_value hdrl_dar_filippenko_refractive_index | ( | hdrl_value | hvL, |
| hdrl_value | hvP, | ||
| hdrl_value | hvT, | ||
| hdrl_value | hvF | ||
| ) |
Compute the refractive index for the given wavelength following Filippenko formulae. This function is called by hdrl_dar_compute().
| hvL | the wavelength (in um) with it error associated |
| hvP | atmospheric pressure (in mmHg) with it error associated |
| hvT | temperature (in degrees Celsius) with it error associated |
| hvF | water vapor pressure (in mmHg) with it error associated |
At sea level (P=760 mm Hg, T = 15 
![\[
(n( \lambda )_{15,760}-1)10^6 = 64.328 + \frac{29498.1}{146-(1/ \lambda )^2} +\frac{255.4}{41-(1/ \lambda )^2}
\]](form_11.png)
where 
![\[
(n(\lambda)_{T,P} -1) = (n(\lambda)_{15,760} - 1) \cdot
\frac{P[1+(1.049-0.0157\ T) 10^{-6}\ P]}{720.883 (1+0.003661\ T)}
\]](form_13.png)
In addition, the presence of water vapor in the atmosphere reduces 
![\[
\frac{0.0624-0.000680/\lambda^2}{1 + 0.003661\ T} f
\]](form_15.png)
here 

![\[
f = 0.75006158 \cdot s_p \cdot h
\]](form_17.png)
where 
Definition at line 426 of file hdrl_dar.c.
Referenced by hdrl_dar_compute().
| hdrl_value hdrl_dar_owens_saturation_pressure | ( | hdrl_value | hvT | ) |
Compute the saturation pressure using the Owens calibration.
| hvT | temperature (in Kelvin) with it error associated (in Celsius) |
![\[
s_p = -10474 +116.43\ T -0.43284\ T^2 +0.00053840\ T^3
\]](form_9.png)
where T is the temperature.
Definition at line 380 of file hdrl_dar.c.
Referenced by hdrl_dar_compute().
| hdrl_parameter * hdrl_dar_parameter_create | ( | hdrl_value | airmass, |
| hdrl_value | parang, | ||
| hdrl_value | posang, | ||
| hdrl_value | temp, | ||
| hdrl_value | rhum, | ||
| hdrl_value | pres, | ||
| cpl_wcs * | wcs | ||
| ) |
Creates DAR parameters object with the values in the header.
| airmass | Air mass |
| parang | Parallactic angle during exposure |
| posang | Position angle on the sky from the angles we have |
| temp | Temperature [Celsius] |
| rhum | Relative humidity [%] |
| pres | Pressure [mbar] |
| wcs | World Coordinate system (WCS) in degrees(CDi_j) |
Definition at line 159 of file hdrl_dar.c.
References hdrl_parameter_delete().