During the reign of King Sejong in the Joseon Dynasty (1433-1438), the Daegyupyo (large gnomon) was produced. The Daegyupyo, with a crossbar (horizontal bar), was used to observe the length of the gnomon’s shadow cast by the sun passing at the meridian. The shadow of this crossbar can be obtained using a measurable device called the Yeongbu (shadow definer). These Daegyupyo and Yeongbu are described in detail in the “Treatise on Astronomy” of Yuan History or “Celestial Spheres and Globes” of Jega-Yeoksang-Jjp (Collected Discourses on the Astronomy and Calendrical Science of the Chinese Masters). According to Jega-Yeoksang-Jjp, the Yeongbu had a structure similar to a door attached to its frame. A pinhole is located in the center of a copper leaf corresponding to the door of the Yeongbu. The image of the sun’s meridian transit and the shadow of the crossbar through the pinhole are projected onto the surface of the Daegyupyo’s ruler stone. Unlike the width and length of the Yeongbu, the height of the Yeongbu is not recorded. This research analyzed the height of the Yeongbu required to maintain the constant distance from the pinhole to the ruler stone surface. Based on these assumptions, it was estimated that 8 to 13 Yeongbu of different heights would be needed for observations using the Daegyupyo in Seoul. To accommodate the need for Yeongbu of various heights, this study proposed a model for a stackable Yeongbu with an adjustable height.

ABSTRACT
1. 서론
2. 대규표와 영부
    2.1. 대규표
    2.2 영부
3. 영부의 구조와 모델 설계
    3.1 영부의 외형
    3.2 영부 초점거리
    3.3 영부의 모델 설계
4. 결론
ACKNOWLEDGMENT
REFERENCES

• 유경한(충북대학교, 충북Pro메이커센터) | GYEONG-HAN YOO (Chungbuk National University, Cheongju 28644, Korea, Chungbuk Pro Maker Center, Cheongju 28644, Korea)
• 김용기(충북대학교, 충북Pro메이커센터) | YONGGI KIM (Chungbuk National University, Cheongju 28644, Korea, Chungbuk Pro Maker Center, Cheongju 28644, Korea)
• 민병희(충북대학교, 한국천문연구원, 과학기술연합대학원대학교) | BYEONG-HEE MIHN (Chungbuk National University, Cheongju 28644, Korea, Korea Astronomy and Space Science Institute, Daejeon 34055, Korea, Korea University of Science and Technology, Daejeon 34113, Korea) Corresponding author
• 김상혁(한국천문연구원) | SANG HYUK KIM (Korea Astronomy and Space Science Institute, Daejeon 34055, Korea)