Uses aperture photometry to make a flux measurement and calculate the centroid coordinates.
Plate.MeasureFlux(X, Y, [InnerAperture], [OuterAperture])
The method syntax has these parts:
| Part | Description |
|---|---|
| X (Integer) | The X coordinate at which the measurement is to be made |
| Y (Integer) | The Y coordinate at which the measurement is to be made |
| [InnerAperture] (Double) | The diameter of the inner aperture (arcseconds, optional, default = 12) |
| [OuterAperture] (Double) | The radius of the outer aperture (arcseconds, optional, default = 24) |
| Return (Double) | The total flux from the object within the aperture, less the background flux in the area (counts) |
This method provides "manual" access to the aperture photometric feature of PinPoint that is used to calculate the sub-pixel centroid position and flux estimate of all objects in the image when Plate.FindImageStars() is called. Normally, scanning is done with the auto-aperture feature enabled (by setting the Plate.InnerAperture and Plate.OuterAperture properties to 0). You can use this method to perform flux measurements for high-precision photometric applications. As a side effect, the method also calculates the centroided X/Y coordinates of the measured object. You may want to use this information to re-center the aperture if needed for a second and possibly more accurate measurement.
The aperture photometry uses circular apertures, with fractional sub-pixel partitioning. The background noise density is measured in the outer aperture and subtracted from the total signal in the inner aperture to yield the net flux from the object. The brightest 10% and faintest 10% of the pixels in the outer aperture are omitted from the background noise measurement, providing some resistance to bleeding in of flux from nearby objects.