Data Naming Convention

NOTE: A suffix _xx below denotes the object identification, where xx = T1, C2, C3, C4, …

Saturated – zero indicates that the peak value of the target and all comparison stars is less than the value set in the “Set_Apertures” module. A number other than zero indicates that highest peak value that exceeded the set limit.

J.D.-2400000 – Julian Day of the observation (UTC based). Availability requires UTC time-of-day information in the FITS header of the observed data.

JD_MOBS – Julian Day of the mid-point of the exposure for this observation (UTC-based). This value is inserted into the FITS header by the Data Processor module when the “FITS Header Updates” option is enabled and target coordinates and observatory geographic location are provided. In addition, UTC time-of-day and exposure time information are required to exist in the FITS header of the observed data.

HJD_MOBS – Heliocentric Julian Day of the mid-point of the exposure for this observation (UTC-based). This value is inserted into the FITS header by the Data Processor module when the “FITS Header Updates” option is enabled and the target coordinates and observatory geographic location are provided. In addition, UTC time-of-day and exposure time information are required to exist in the FITS header of the observed data.

BJD_MOBSBarycentric Julian Day of the mid-point of the exposure for this observation (BJDTDB-based). This value is inserted into the FITS header by the Data Processor module when the “FITS Header Updates” option is enabled and the target coordinates and observatory geographic location are provided. In addition, UTC time-of-day and exposure time information are required to exist in the FITS header of the observed data.

ALT_OBJ – altitude above the horizon of the target object at mid-exposure. This value is inserted into the FITS header by the Data Processor module when the “FITS Header Updates” option is enabled and the target coordinates and observatory geographic location are provided. In addition, UTC time-of-day and exposure time information are required to exist in the FITS header of the observed data.

AIRMASS – airmass of the target object at mid-exposure. This value is inserted into the FITS header by the Data Processor module when the “FITS Header Updates” option is enabled and the target coordinates and observatory geographic location are provided. In addition, UTC time-of-day and exposure time information are required to exist in the FITS header of the observed data.

Source_Radius – radius of the aperture used to calculate the photometric values

Sky_Radius(min) – radius of the inner edge of the annulus used to calculate the sky background

Sky_Radius(max) – radius of the outer edge of the annulus used to calculate the sky background

X(IJ)_xx – x-location in ImageJ coordinates of the center of the aperture located at object xx

Y(IJ)_xx – y-location in ImageJ coordinates of the center of the aperture located at object xx

X(FITS)_xx – x-location in FITS coordinates of the center of the aperture located at object xx

Y(FITS)_xx – y-location in FITS coordinates of the center of the aperture located at object xx

rel_flux_T1 – the ratio of target T1’s net integrated counts to the total of all comparison star net integrated counts. Mathematically the value is Source-Sky_T1 / (Source-Sky_C2 + Source-Sky_C3 + Source-Sky_C4 + …).

rel_flux_Cx – the ratio of the comparison star Cx’s net integrated counts to the total of all OTHER comparison star net integrated counts. This value requires at least two comparison stars be selected during a Multi-aperture run. Mathematically the value is Source-Sky_Cn / (SumOf(Source-Sky_Cx)), where x not equal n. For clarification, the target star T1’s net integrated counts are not used for these calculations.

rel_flux_err_xx – the error in the relative flux for object xx. The error is calculated by propagating all Source_Error_xx values through the equations defined for rel_flux_xx above.

rel_flux_SNR_xx – signal-to-noise ratio for rel_flux_xx. This value is simply rel_flux_xx / rel_flux_err_xx.

Source-Sky_xx – net integrated counts within the aperture located at object xx. Net integrated counts is defined as the sum of all pixels whose center falls within the aperture source radius, less the sky background per pixel. Sky background is either the average value of the pixels in the annulus defined by Sky_Radius(min) and Sky_Radius(max), or the value from a plane fitted to the values in the sky annulus. The user can select which method to use for calculation of sky background in the “Set_Aperture” module.

Source_Error_xx – error in Source-Sky_xx. The calculation includes contributions from read-out-noise, dark current, and source and sky poisson noise as defined by Merline, W. & Howell, S.B., 1995, EXP. ASTRON., 6, 163. The equation is:
SourceError = SquareRoot ((NetSourceCounts * gain +SourcePixelCount * (1 + SourcePixelCount / SkyPixelCount) * (TotalSkyCounts * CCDgain + DarkNoisePerPixel + ReadOutNoisePerPixel * ReadOutNoisePerPixel + CCDgain * CCDgain * 0.289)) / CCDgain)

Source_SNR_xx – signal-to-noise ratio for Source-Sky_xx. This value is simply Source-Sky_xx / Source_Error_xx.

tot_C_cnts – the sum of all comparison star net integrated counts. tot_C_cnts = Source-Sky_C2 + Source-Sky_C3 + …

tot_C_err – the error in tot_C_cnts. The error is calculated by combining Source_Error_C2 + Source_Error_C3 + … in quadrature.

tot_C_cnts-Cn – the sum of all comparison star net integrated counts excluding object Cn. tot_C_cnts-Cn = SumOf(Source-Sky_Cx), where x includes all defined apertures >= 2, except aperture n.

tot_C_err-Cn – the error in tot_C_cnts-Cn. The error is calculated by combining all Source_Error_Cx in quadrature, where x includes all defined apertures >= 2, except aperture n.

Peak_xx – the highest pixel value less the sky-background within the aperture for object xx.

Sky/Pixel_xx – the average pixel value within the sky-background annulus for object xx.

X-Width_xx – the X-direction FWHM of the PSF of object xx. The aperture radius must extend beyond the object’s PSF for this number to be accurate.

Y-Width_xx – the Y-direction FWHM of the PSF of object xx. The aperture radius must extend beyond the object’s PSF for this number to be accurate.

Width_xx – the mean of the X- and Y-direction FWHM of object xx. The aperture radius must extend beyond the object’s PSF for this number to be accurate.