We measure the baryon acoustic oscillation (BAO) observables
,
, and
as a function of red shift
z in the range 0.1 to 0.7 with Sloan Digital Sky Survey (SDSS) data release DR13. These observables are independent and satisfy a consistency relation that provides discrimination against miss-fits due to background fluctuations. From these measurements and the correlation angle
of fluctuations of the Cosmic Microwave Background (CMB), we obtain
,
and
for dark energy density allowed to vary as
. We present measurements of
at six values of the expansion parameter
a. Fits with several scenarios and data sets are presented. The data is consistent with space curvature parameter
and
constant.