On 2022 September 26, NASA's DART mission intentionally impacted Dimorphos, the moon of near-Earth asteroid (65803) Didymos, changing the binary system's orbital period. The system was studied intensively from the ground over the ensuing months until February 2023 when its brightness and low solar elongation precluded further observations. These observations revealed a clear period change of 33 minutes due to the DART impact (Thomas et al. 2023). However, there is uncertainty on whether there was a single impulsive change in the orbital period resulting in a constant post-impact value, or if there is (or was) an evolution in the period with time as the system settled into a new configuration. Careful analysis of the full post-DART lightcurve dataset (through February 2023) showed that there was insufficient data to distinguish between constant or changing post-impact orbital periods (Naidu et al. 2024, Scheirich et al. 2024). In order to understand the final outcome of the DART mission, it is therefore critical to monitor the evolution of the Didymos system prior to the European Space Agency's Hera mission arrival in late 2026. Observations from Hera will be too far removed from the time of impact to reveal whether or not the orbit period was changing over months as the asteroid system reached a new equilibrium. Our team obtained data during 2024 June to August on Magellan (6.5-m, PI: Thomas), SOAR (4.1-m, Program ID 2024A-120042), NTT (3.6-m, PI: Snodgrass), and Faulkes Telescope South (2-m, PI: Lister), but poor weather at all sites plus Didymos's positioning in front of the galactic plane throughout the visibility window prevented our analyses from attaining the needed sensitivity. The next visibility window occurred from late January through early March 2025, and our team was awarded time on Faulkes Telescope North (FTN, 2-m, PI: Lister), Lowell Discovery Telescope (LDT, 4.3-m, PI: Moskovitz), Palomar (5.1-m, PI: Chesley), Gemini-N (8.1-m, Program ID GN-2025A-Q-142), and Gran Telescopio Canarias (GTC, 10.4-m, PI: de Leon). Here we report on Gemini-N observations obtained on 2025 February 24, 26, and 28 when Didymos was at an apparent V magnitude about 20.3. The GTC observing run was weathered out. Observations acquired with FTN, LDT, and Palomar were successfully acquired, but are still being analyzed. Our Gemini observations were timed to optimize coverage of the Didymos binary orbit within the run and to provide complementary observations with neighboring runs scheduled on Palomar and GTC. We observed Didymos for 3.7 hr at the start of each night using the SDSS-i filter. We tracked at the sidereal rate and limited individual exposure times to 20 sec to keep the asteroid's trailing from significantly exceeding the stellar point spread function. Images were processed using the Gemini DRAGONS pipeline (Labrie et al. 2023) and photometry was measured using Photometry Pipeline (Mommert 2017). After manually removing frames that were contaminated by nearby stars or other image artifacts, lightcurve deconvolution was performed using the binary asteroid lightcurve decomposition method as earlier Didymos datasets (Pravec et al. 2022, 2024). Our preliminary analysis finds that mutual events occurred about 70 min earlier than the nominal prediction (see Figure 1), a difference of 1.6-sigma. This yields a binary orbital period of 11.3667 +/- 0.0002 hr (3-sigma), assuming that the period has been constant since 2022/2023. With the much longer time baseline, these observations reduce the uncertainty in the binary period by about a factor of 6 compared to the previously published 3-sigma measurement of 11.3675 +/- 0.0012 hr (Scheirich et al. 2024). As expected, the data quality was insufficient to constrain Dimorphos' rotation (which needed rms residuals of 0.004-0.007 mag, while residuals of 0.017 mag were obtained). Deep stacking of all images collected on a night did not reveal evidence of a tail or any remaining large fragments, though we have not yet quantified these non-detections. We will provide updated results on the full 2025 dataset. If ongoing analyses of the FTN, LDT, and/or Palomar datasets yield sufficiently small rms residuals, the lightcurve deconvolution will be re-run on the larger dataset, though the solution is not expected to change appreciably. The question of whether or not the orbital period has changed or if the apparently shorter period is just a statistical fluke is unlikely to be resolved from these data since they were all acquired relatively close to the Gemini observations. We plan to propose for similar observations during Didymos's next apparition in 2026 July to attempt to resolve this question.Acknowledgements: The work at Ondřejov has been supported by the "Praemium Academiae" award by the Academy of Sciences of the Czech Republic, grant AP2401.References Labrie et al., RNAAS 7, id.214 (2023) Mommert, M. Astronomy & Computing 18, 47 (2017) Naidu et al., PSJ 5, 74 (2024) Pravec et al., PSJ 3, 175 (2022) Pravec et al., Icarus 418, id.116138 (2024) Scheirich et al., PSJ 5, 17 (2024) Thomas et al., Nature 616, 448 (2023) Figure 1: Decomposition of Didymos system lightcurve from 2025 February 24-28 (a) into signals from mutual events (b), and primary rotation (c). The top panel (a) shows the combined lightcurve over 11.37 hr. The full lightcurve can be decomposed into a contribution from the 2.260-hr rotation of Didymos (bottom panel c) and a contribution due to mutual events. The mutual events are indicated by horizontal lines underneath the lightcurve in panel (b). The blue lines are the observed mutual events (PE = primary eclipse, PO = primary occultation, SE = secondary eclipse, SO = secondary occultation), while the red lines are the nominal predictions of these same events from Scheirich et al. (2024), which occurred ~70 minutes later than observed.