  We analyze a [C II] 158 micron map obtained with the L2 GREAT receiver on
SOFIA of the emission/reflection nebula illuminated by the early B star S1 in
the rho-OphA cloud core. This data set has been complemented with maps of
CO(3-2), 13CO(3-2) and C18O(3-2), observed as a part of the JCMT Gould Belt
Survey, with archival HCO^+(4-3) JCMT data, as well as with [O I] 63 and 145
micron imaging with Herschel/PACS. The [C II] emission is completely dominated
by the strong PDR emission from the nebula surrounding S1 expanding into the
dense Oph A molecular cloud west and south of S1. The [C II] emission is
significantly blue shifted relative to the CO spectra and also relative to the
systemic velocity, particularly in the northwestern part of the nebula. The [C
II] lines are broader towards the center of the S1 nebula and narrower towards
the PDR shell. The [C II] lines are strongly self-absorbed over an extended
region in the S1 PDR. Based on the strength of the [13C II] F = 2-1 hyperfine
component, [C II] is significantly optically thick over most of the nebula. CO
and 13CO(3-2) spectra are strongly self-absorbed, while C18O(3-2) is single
peaked and centered in the middle of the self-absorption. We have used a simple
two-layer LTE model to characterize the background and foreground cloud
contributing to the [C II] emission. From this analysis we estimate the
extinction due to the foreground cloud to be ~9.9 mag, which is slightly less
than the reddening estimated towards S1. Since some of the hot gas in the PDR
is not traced by low J CO emission, this result appears quite plausible. Using
a plane parallel PDR model with the observed [OI(145)]/[C II] brightness ratio
and an estimated FUV intensity of 3100-5000 G0 suggests that the density of the
[C II] emitting gas is ~3-4x10^3 cm^-3.
