We present two transit observations of the inflated hot Jupiter WASP-52b (K2V host, ), obtained in the RC and V bands, alternated frame by frame using a single camera on a 0.3 m Newtonian telescope at the P64 Observatory, an urban site in Suwon, Korea, on UT 2024 August 30 and September 27. The data were reduced using a pipeline designed for urban small-telescope photometry that mitigates two reduction-induced systematics capable of mimicking a transit: the use of a per-frame, seeing-proportional aperture, and the saturation of bright targets. When applied to a blend-contaminated comparison-star ensemble, a seeing-scaled aperture inflated the fitted radius ratio by approximately a factor of two, whereas a fixed aperture recovered the literature value from the same ensemble. Thus, the seeing-coupled aperture does not bias the transit depth by itself but can amplify defects in the comparison-star ensemble, such as blended neighbours, into a transit-shaped systematic; using a fixed aperture suppresses this effect. The controlled pipeline employs a fixed aperture (3.5 times the nightly median stellar full width at half maximum, FWHM, with a minimum of 12 pixels), per-star centroiding, sigma-clipped sky estimation, and frame-level saturation control. The highersignal- to-noise 2024 August 30 light curve yields a planet-to-star radius ratio of Rp/Rs = 0.172 ± 0.016, consistent within 0.5 with the literature value of 0.1646. The shorter-exposure September 27 epoch gives 0.191 ± 0.035, and the weighted mean is 0.175 ± 0.014; all uncertainties include an a posteriori red-noise assessment ( = 1.0 and 1.5). The August 30 mid-transit time agrees with the discovery ephemeris (OC = +1.4 ± 5.1 min, approximately 2,700 orbits after discovery), confirming the ephemeris to within ±5 min. Although based on only two transits obtained from a single site and instrument, these results suggest that urban 0.3 m telescopes can contribute useful photometry to ephemeris-maintenance efforts such as ExoClock in support of ESA’s Ariel mission.

Abstract
1. Introduction
2. Observations and Methods
3. Results
4. Discussion
5. Conclusions
References

• Kiehyun Park(Cheolsan Middle School, Gwangmyeong 14243, Korea) Corresponding author
• Hyunjong Kim(Songtan High School, Pyeongtaek 18007, Korea)