Journal of the Korean earth science society (한국지구과학회지)

The Korean Earth Science Society (한국지구과학회)
권호 표지
DOI QR코드

DOI QR Code

Measuring Night Sky Brightness over the Downtown Using a DSLR Camera

DSLR 카메라를 이용한 도심지의 밤하늘 밝기 측정

  • Lee, Dongseob (Department of Earth Science Education, Kyungpook National University) ;
  • Shim, Hyunjin (Department of Earth Science Education, Kyungpook National University)
  • 이동섭 (경북대학교 지구과학교육과) ;
  • 심현진 (경북대학교 지구과학교육과)
  • Received : 2019.09.27
  • Accepted : 2019.10.15
  • Published : 2019.10.31
Download PDF
⟨ Previous Next ⟩

Abstract

We measured night sky brightness (NSB) over the downtown using a Digital Single Lens Reflex (DSLR) camera combined to a small telescope for educational purpose, considering that most secondary schools are located in urban areas and have limitation in the equipment for astronomical observation. Raw format images from DSLR camera are not affected by various camera settings except for the ISO, and the typical photometric uncertainty including filter transformation is about 0.1 mag. Near the zenith, the NSB of the B, V, and r-band is 17.5, 17.1, and $16.9mag\;arcsec^{-2}$, respectively. The approximate limiting magnitude is derived to be 17.5 mag at B-band and 17 mag at V, r-band. A large scale artificial light close to the observation site is the dominant cause for making observing condition worse, increasing the NSB by $0.6mag\;arcseec^{-2}$ regardless of the altitude and filter.

대부분의 중 고등학교가 도심지에 위치하며 사용할 수 있는 천문 관측 장비에 제한이 있다는 점을 고려하여 DSLR 카메라와 교육용 소형 망원경을 결합하여 도심지 밤하늘 밝기를 측정하였다. DSLR 카메라의 다양한 설정은 ISO 설정 외에는 원본 파일에 영향을 주지 않았으며, 필터 변환까지 고려한 일반적인 측광 정밀도는 대략 0.1 등급이다. 밤하늘 밝기는 천정 부근의 경우 B, V, r 필터에서 각각 약 17.5, 17.1, $16.9mag\;arcsec^{-2}$으로 측정되었다. 이를 통해 도심지의 대략적인 한계등급은 B 필터에서 17.5 등급, V와 r 필터에서 17등급으로 추정할 수 있다. 관측지점과 가까운 대규모 인공 조명은 고도와 필터에 무관하게 밤하늘 밝기를 약 $0.6mag\;arcsec^{-2}$ 증가시킴으로써 관측 환경을 악화시키는 주요인으로 나타났다.

Keywords

References

  1. An, S.-H., Bae, H.-J., Yu, J., Roh, E., Chiang, H., Kim, J., Kim, S., and Park, S., 2015, The second survey of night sky brightness in the capital region of Korea, The bulletin of the Korean astronomical society, 40(1), 882. (in Korean)
  2. Andreic, Z., 2018, Night sky brightness above Zagreb 2012.-2017., The mining geological petroleum engineering bulletin, 33(3), 85-94.
  3. Boo, G.-W., Gill, Y., Sohn, J., Kim, S., 2013, Sunspots observation using DSLR and measuring the differential rotation period, The Korean society for school science, 7(3), 182-192. (in Korean)
  4. Buchheim, R., Collins, D., Hager, T., Manske, B., and Templeton, M., 2016, Image acquisition and processing. In Blackford, M. (ed.), The AAVSO DSLR observing manual. American association of variable star observers, Cambridge, MA, USA, 38 p.
  5. Buil, C., 2005, IRIS: Astronomical image-processing software. In Ratledge, D. (ed.), Digital astrophotography: The state of the art. Springer-Verlag London Limited, London, UK, 79-88.
  6. Falchi, F., Cinzano, P., Duriscoe, D., Kyba, C.C.M., Elvidge, C.D., Baugh, K., Portnov, B.A., Rybnikova, N.A., and Furgoni, R., 2016, The new world atlas of artificial night sky brightness, Science advances, 2(6), e1600377. https://doi.org/10.1126/sciadv.1600377
  7. Garstang, R.H., 1986, Model for artificial night-sky illumination, Publications of the astronomical society of the Pacific, 98, 364-375. https://doi.org/10.1086/131768
  8. Guo, D.-F., Hu, S.-M., Chen, X., Gao, D.-Y., and Du, J.-J., 2014, Sky brightness at Weihai observatory of Shandong university, Publications of the astronomical society of the Pacific, 126, 496-503. https://doi.org/10.1086/676819
  9. Henden, A. and Munari, U., 2014, The APASS all-sky, multi-epoch BVgri photometric survey, Contributions of the astronomical observatory Skalnate Pleso, 43(5), 518-522.
  10. Hoot, J.E., 2007, Photometry with DSLR cameras, In Warnet B.D. et al. (eds.), Proceedings for the 26th annual conference of the society for astronomical sciences, Society for astronomical sciences, Rancho Cucamonga, CA, USA, 67-72.
  11. Kim, S.-H., Lee, H., Lee, H.-D., and Jeong, J.-H., 2008, Development and application of an after-school program for an astronomy observation club in a highschool: Standardized coefficient decision program in consideration of the observation site's environment, Journal of Korean earth science society, 29(6), 495-505. (in Korean) https://doi.org/10.5467/JKESS.2008.29.6.495
  12. Kloppenborg, B.K., Pieri, R., Eggenstein, H.-B., Maravelias, G., and Pearson, T., 2012, A demonstration of accurate wide-field V-band photometry using a consumer-grade DSLR camera, Journal of the American association of variable star observers, 40(2), 815-833.
  13. Lee, J., Choe, S.-U., Jung, J.-H., and Woo, H.-G., 2009, Astronomical observation environment study focusing on night sky brightness variation under light pollution, Journal of the Korean earth science society, 30(3), 344-353. (in Korean) https://doi.org/10.5467/JKESS.2009.30.3.344
  14. Loughney, D., 2010, Variable star photometry with a DSLR camera, Journal of the British astronomical association, 120(3), 157-160.
  15. Mauer, C., 2009, Measurement of the spectral response of digital cameras with a set of interference filters (Thesis at the department of media and phototechnology), University of applied sciences cologne.
  16. Park, W., Pak, S., Shim, H., Le, H.A.N., Im, M. Chang, S., and Yu, J., 2016, Photometric transformation from RGB Bayer filter system to Johnson-Cousins BVR filter system, Advances in space research, 57(1), 509-518. https://doi.org/10.1016/j.asr.2015.08.004
  17. Pilachowski, C.A., Africano, J.L., Goodrich, B.D., and Binkert, W.S., 1989, Sky brightness at the Kitt Peak national observatory, Publications of the astronomical society of the Pacific, 101, 707-712. https://doi.org/10.1086/132494
  18. Pun, C.S.J., So, C.W., Leung, W.Y., and Wong, C.F., 2014, Contributions of artificial lighting sources on light pollution in Hong Kong measured through a night sky brightness monitoring network, Journal of quantitative spectroscopy and radiative transfer, 139, 90-108. https://doi.org/10.1016/j.jqsrt.2013.12.014
  19. Puschnig, J., Schwope, A., Posch, T., and Schwarz, R., 2014, The night sky brightness at Potsdam-Babelsberg including overcast and moonlit conditions, Journal of quantitative Spectroscopy and radiative transfer, 139, 76-81. https://doi.org/10.1016/j.jqsrt.2013.12.011
  20. Ryu, S.-R. and Lee, T.D., 2013, Observation of the surface of the sun by using a small telescope and solar filters, New physics: Sae Mulli, 63(2), 219-225. (in Korean) https://doi.org/10.3938/NPSM.63.219
  21. Shim, H., 2017, Evaluation of popular photometry analysis software using DSLR camera, Journal of Korean earth science society, 38(5), 323-332. https://doi.org/10.5467/JKESS.2017.38.5.323
  22. Tody, D., 1986, The IRAF data reduction and analysis system. In Crawford, D.L. (ed.), Instrumentation in Astronomy VI., Society of photo-optical instrumentation engineers, Bellingham, WA, USA, 733-752.
  23. Zacharias, N., Finch, C.T., Girard, T.M., Henden, A., Bartlett, J.L., Monet, D.G., and Zacharias, M.I., 2013, The fourth US Naval Observatory CCD astrograph catalog (UCAC4), The astronomical journal, 145(2), 44-57. https://doi.org/10.1088/0004-6256/145/2/44