deletions | additions       diff --git a/subsection_Photometric_Accuracy_textbf_Relative__.tex b/subsection_Photometric_Accuracy_textbf_Relative__.tex  index a42faab..827b5d4 100644  --- a/subsection_Photometric_Accuracy_textbf_Relative__.tex  +++ b/subsection_Photometric_Accuracy_textbf_Relative__.tex 
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\begin{tabular}{ rrrr }  Quantity & Design Spec & Minimum Spec & Stretch Goal \\  \hline  PA5 (mmag) &10 &15  & 15 20  & 5 10  \\ \hline  \end{tabular}   \caption{\label{tbl:color_zp} The specifications for the color spatial uniformity of the photometric  zeropoints.} \end{table}  This requirement is primarily driven by supernovae and the ability to accurately determine their distance modulii based on color-curves.  \textbf{Absolute Photometric Calibration} Many of the ``bread and butter'' science goals of ZTF require a precise and accurate absolute photometric calibration (e.g., cosmography with Type Ia SNe, mapping Galactic structure with RRL). Recently, PS1 has demonstrated the ability to produce an absolute calibration, relative to the Sloan Digital Sky Survey and \textit{Hubble Space Telescope} Calspec stars of $\sim$30 mmag \citep{Tonry_2012}. PTF achieved $20\,\textrm{mmag}$ scatter compared with the SDSS \citep{Ofek_2012}. However, since PTF observed mostly in a single filter, one needs to know the star color in order to achieve the this accuracy.  The first requirement is that ZTF will observe the sky in at least two bands.  The second requirement is that it will have uniformity of better than 20\,mmag over the entire sky,