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tokens: The fall-off dependence of the dark-energy density as a function of r is given by the parameter n (c.f. eq. 1 in paper II). For a value of n = 3 the dark-energy density versus radius dependence does not contradict the tests of standard GR in the Solar system. Nielsen Birnholz ( 2018 ) have pointed out that a larger value of n is required to account for the results obtained from gravitational wave observations (c.f. their eq. 4). Paper II shows that for larger values of n , the predicted intensity and velocity structures will be almost identical within pc-GR, with only slight changes in the absolute values. For instance, increasing n from 3 to 4 results in a shift in the maximum orbital frequency from 1.72 to 1.89 m and a shift in the maximum orbital frequency from 0.21 to 0.22 (c.f. eq. 4 of paper II and Fig. 2 in this paper). Therefore the appearance of a dark and a bright ring in the intensity profiles discussed in Section 2 are robust and will not change for steeper values of n . In this paper we assume a value of n = 4 for the tests on the timing properties to account for the detection of gravitational waves. We assume a value of n = 3 for the ray-tracing simulations, as the structures in the intensity behaviour will not change. The Galactic Centre has been studied in great detail with near-infrared observations. Based on the orbital motions of stars in the vicinity of the Galactic Centre, the mass of the central black hole has been constrained to [Gillessen et al. ( 2009 ), see also Genzel et al. ( 1996 ) and Eckart Genzel ( 1997 )]. Gravity Collaboration et al. ( 2018a ) have, for the first time, measured the gravitational redshift of the star S2 near the Galactic Centre. In addition, Gravity Collaboration et al. ( 2018b ) have detected bright flares at distances of approximately 150 μas from the central black hole. In this paper we summarize our imaging and timing predictions based on the pc-GR theory for the Galactic Centre. In Section 2.1 the ray-tracing simulations are summarized. In Section 2.2 we predict the orbital velocities of particles which can be compared to Event Horizon Telescope (EHT) observations at different epochs. Finally in Section 2.3 we compare the emission profiles predicted by pc-GR and standard GR, which show remarkable differences. The theory of pc-GR in general, along with a specific focus on the tests discussed in this work, is presented in Hess et al. ( 2019 ) (hereafter Paper II : Theory and robust predictions). 2 OBSERVATIONAL TESTS In this section we describe the observational tests we have developed to date to verify the predictions of the pc-GR theory in preparation for the upcoming EHT observations. These tests include ray-tracing simulations of the flow of accreting matter around black holes using both standard GR and pc-GR. In addition, we have produced diagnostic plots comparing both theories with regard to emissivity profiles and the timing properties of orbiting matter. The main results are