CApphot Class Description
The CApphot class manages the operation of aperture photometry routines. These routines are used for computing the total brightness of a point sources. For astronomical applications, this is used to measure stars and other objects that are unresolved or of small angular extent. The aperture may be a circle or an ellipse. The background is subtracted from the measurement and may be computed locally or assigned a specified value.
Construction |
Object = CApphot:new() |
Destruction |
Object:delete() |
This class contains numerous properties that describe the measurement. These are used to pass data to and from the photometry functions. See CApphot Properties. Values returned by the GetImageParams and Measure methods also used class properties and may be retrieved using either the properties or the Accessor Methods below.
Creates a new instance of the CApphot class. There are 2 constructor formats. |
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Deletes the instance of the CApphot object. |
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Copies the properties of this CApphot object to a new CApphot object. |
Reads the image header and fetches the values of camera gain, readout noise, exposure time, and the photometric zero point and its error. These values are returned as class properties. See CApphot Properties. |
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Performs an aperture photometry measurement at a (column,row) coordinate in an image. |
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Sets the method used to evaluate the background in the Measure method. Four options are provided: mean, median, mode, and value. |
These methods return values of class properties.
Returns an integer number indicating the status returned by the Measure and GetImageParams methods.
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Returns a string indicating "Success" or the error message generated by the photometry method (see GetStatusCode). |
Returns the X position of the center of the measuring apertures. |
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Returns the Y position of the center of the measuring apertures. |
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Returns the net count for the object, measured in counts (or "ADU" or "DN"). If the bRemoveBg flag is true, this is the net count above the background. Otherwise, this gives the total count above zero. |
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Returns the uncertainty in the net count for the object, measured in counts (or "ADU" or "DN"). |
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Returns the theoretical uncertainty in the net count for the object, measured in counts (or "ADU" or "DN"). |
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Returns the background value per pixel, measured in counts (or "ADU" or "DN"). If the bRemoveBg flag is true, this value was subtracted from the total to calculate nNetCount. This is identical to the BgCount method in previous versions. |
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Returns the error in the background value (per pixel). This is a 1-sigma mean error, not the error of the mean background, and is measured in units of counts (or "ADU" or "DN"). If the bRemoveBg flag is true, this value was subtracted from the total count to calculate nNetCount. This is identical to the BgCountErr method in previous versions. |
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Returns the measured magnitude of the object. If the bApplyZeroPt flag was true, this includes the photometric zero point set in the nZeroPt value. |
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Returns the random error in the value of nMag as calculated from the noise measured in the background sample. If the bApplyZeroPtErr flag was true, this includes the photometric zero point error set in the nZeroPtErr value. This is identical to the MagError method in previous versions. |
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Returns the theoretical random error in the value of nMag as calculated using only the instrumental values but not the actual noise measured in the background sample. If the bApplyZeroPtErr flag was true, then this includes the photometric zero point error set in the nZeroPtErr value. This is identical to the MagErrorT method in previous versions. |
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Returns the Signal to Noise Ratio of the signal measured inside the object aperture of radius nRadius1. |
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Returns the theoretical Signal to Noise Ratio of the signal measured inside the object aperture of radius nRadius1. |