This study aimed to standardize the BVR CCD photometry system of the Gwangju Science High School Observatory. We have observed Landolt standard stars using the CDK14 telescope and the STX-16803 CCD camera and carried out the data reduction by Maxim DL. As a result, we estimated the atmospheric extinction coefficients using the observation on August 29 and 31, 2024. By a standardization procedure, we calculated instrumental magnitudes and color indices outside the atmosphere. The instrumental magnitudes of celestial objects measured on the ground by the atmospheric correction were successfully transformed into standard magnitudes, with the standardization conversion formulas provided as following equations.                         The observational analysis revealed that atmospheric extinction coefficients vary depending on the observing conditions and that extinction increases at short wavelength. Additionally, the B filter exhibited significant second-order extinction effects due to color indices, suggesting the necessity of applying second-order atmospheric extinction coefficients for precise observations. This study suggests that Gwangju Science High School Observatory can serve as reliable resources for both educational and research purposes. Furthermore, this study demonstrates the potential for producing high-precision photometric data that meet international standards, even at a secondary school-level observatory. These findings are expected to contribute significantly to future astronomical education and research.

ABSTRACT
1. 서론
2. 연구 방법
    2.1 광주과학고등핚교 천문대 측광계 특성
    2.2 표준성 선정 및 관측
3. 연구 결과
    3.1 측광 및 자료 분석
    3.2 1차 대기소광계수 및 고유 등급
    3.3 표준화 계수
    3.4 2차 대기소광계수 및 고유 등급의 필터별 색효과
4. 결론 및 제언
ACKNOWLEDGEMENT
REFERENCES

• 조현웅(광주과학고등학교, 전남대학교 대학원 과학교육학과) | HYUN-WUNG CHO (Gwangju Science Academy for the Gifted, Gwangju, 61005, Korea, Department of Science Education, Chonnam National University, Gwangju, 61186, Korea)
• 강원석((주)스페이스빔) | WONSEOK KANG (Spacebeam Inc., Cheongju, 28165, Korea)
• 오수연(전남대학교 지구과학교육과) | SUYEON OH (Department of Earth Science Education, Chonnam National University, Gwangju 61186, Korea) Corresponding author