deletions | additions       diff --git a/Observations.tex b/Observations.tex  index 8a68e73..41b88ce 100644  --- a/Observations.tex  +++ b/Observations.tex 
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\citep{Benitez:2000}, and $z=0.92\pm0.05$, derived using the EAZY  program \citep{Brammer:2008}.  Table~\ref{tab:Photometry} presents photometry of the \spock\ events from all available HST observations. The flux was measured on difference images, first  using both simple apertures aperture photometry with a 0\farcsec3 radius,  and also  by fitting with an empirical point spread function (PSF). The PSF model was defined using HST observations of  the DA white dwarf G2V standard  star P330E, observed in a separateHST  calibration program. Owing A separate PSF model was defined for each filter, but owing  to the long-term stability of the HST PSF, PSF  we made no corrections to used  the PSF same  model epoch by epoch. in all epochs. All of the aperture and PSF fitting photometry was carried out using the {\tt PyPhot} software package \citep{Jones:2015}.  TODO : add more detail on aperture and psf photometry?  TODO: add a table with photometry.     
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