• 한국지구과학회지
• /
• 제33권7호
• /
• pp.608-617
• /
• 2012

분해능이 ${\Delta}{\lambda}{\sim}-0.1{\AA}$인 고분산 분광기를 사용하여 공생별 Z Andromedae (And)의 분광자료를 연구하였다. 분광 관측은 (1) 2001년 8월 30일(위상 ${\Phi}$=0.77)과 2002년 8월 12일(위상 ${\Phi}$ =0.22)에 Lick 천문대의 Hamilton Echelle Spectrograph (HES)를 사용하여, 1800초와 3600초 노출의 고분산 자료를 얻었으며, (2) 2009년 10월 21일(위상 ${\Phi}$=0.70)에는 보현산 천문대의 Bohyunsan Echelle Spectrograph (BOES)를 사용하여 1200초 노출 시간의 고분산 자료를 얻었다. 약 $3600{\AA}-9500{\AA}$파장대의 HES와 BOES 관측 자료로 부터 HI, HeI, HeII에 대한 방출선을 선택하여 분석하였다. 이 선들의 선 윤곽 분석 작업을 통해 2개 또는 3개로 분리시키고, 위상별로 각 성분이 어떤 지역에서 형성되고, 백색왜성과 적색거성의 궤도 운동과 어떠한 관련이 있는지를 조사하였다. 라만 산란(Raman scattering)된 $H{\alpha}$선 선폭 및 HI, HeI, HeII의 위상별 변화를 보이는 방출선의 특성으로부터, 방출선들은 백색왜성 주위를 감싸는 강착원반과 이 원반 안의 두 라그랑지안(Lagrangian) 포인트 $L_1$과 $L_2$지역에서 주로 생성된 것으로 결론지었다. Z And는 활동성이 2009년과 2001년에 가장 활발했고, 2002년의 선 윤곽은 매우 복잡한 양상을 보임에도 불구하고, 활동성은 비교적 조용하였음을 암시하고 있다.

• 복식
• /
• 제5권
• /
• pp.141-152
• /
• 1981

Various ceremonial flags were of great importance to the rulers who wished to have the absolute authorities for governing the people. Perhaps nothing indicated the ideas, thoughts and symbols of a certain period and people than the ceremonial flags. The ceremonial flags used in the old China and Korea took the shapes of the heaven and the earth, representing the social backgrounds and thoughts. This study was limited only to the discussion of the heaven-shaped patterns of the ceremonial flags. The 28 constellations of the heaven, in the Oriental way of thinking, were considered to express the immortal powers of Providence and the political domination of the earth. Hence the Polaris, the center of the heaven, symbolized the whole family of king, prince, child born of a concubine and royal harem. Among the constellation pictures were those of Han period, wall painting of old tombs in Koguryeo kingdom and old Japanese kingdom. Referring to the Emperor's ceremonial flags in Daemyeongjibyei, symbolic meanings changed historically and the complete systems of the ceremonial flags were established in Song period when the divine person was drawn on the flags. Animals concerned properly with the particular star and the shapes of the star were both drawn on the flags in Won period and only the shapes of the particular star in Myeong period. In the Imperial enthronement of Kojong the ceremonial flags might be made by the examples of those of Myeong period and remains are now found at Changdeok Palace, which need a further study because the references in detail are not available.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.1867-1870
• /
• 2005

The celestial navigation is one of alternatives to GPS system and can be used as a backup of GPS. In the celestial navigation system using more than two star trackers, the vehicle's ground position can be solved based on the star trackers' attitude information if the vehicle's local vertical or horizontal angle is given. In order to determine accurate ground position of flight vehicle, the high accurate local vertical angle measurement is one of the most important factors for navigation performance. In this paper, the Earth geophysical deflection was analyzed in the assumption of using the modern electrolyte tilt sensor as a local vertical sensor for celestial navigation system. According to the tilt sensor principle, the sensor measures the tilt angle from gravity direction which depends on the Earth geoid surface at a given position. In order to determine the local vertical angle from tilt sensor measurement, the relationship between the direction of gravity and the direction of the Earth center should be analyzed. Using a precision orbit determination software which includes the JGM-3 Earth geoid model, the direction of the Earth center and the direction of gravity are extracted and analyzed. Appling vector inner product and cross product to the both extracted vectors, the magnitude and phase of deflection angle between the direction of gravity and the direction of the Earth center are achieved successfully. And the result shows that the angle differences vary as a function of latitude and altitude. The maximum 0.094$^{circ}$angle difference occurs at 45$^{circ}$latitude in case of 1000 Km altitude condition.

• Journal of Astronomy and Space Sciences
• /
• 제28권4호
• /
• pp.273-284
• /
• 2011

A method of stellar source selection for validating the quality of image is investigated for a low Earth orbit optical remote sensing satellite. Image performance of the optical payload needs to be validated after its launch into orbit. The stellar sources are ideal source points that can be used to validate the quality of optical images. For the image validation, stellar sources should be the brightest as possible in the charge-coupled device dynamic range. The time delayed and integration technique, which is used to observe the ground, is also performed to observe the selected stars. The relations between the incident radiance at aperture and V magnitude of a star are established using Gunn & Stryker's star catalogue of spectrum. Applying this result, an appropriate image performance index is determined, and suitable stars and areas of the sky scene are selected for the optical payload on a remote sensing satellite to observe. The result of this research can be utilized to validate the quality of optical payload of a satellite in orbit.

• Journal of Astronomy and Space Sciences
• /
• 제9권1호
• /
• pp.111-119
• /
• 1992

The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately 30000K, based on the flux distributions during egress. Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 2350 ${\AA}$, 2550 ${\AA}$ and 2850 ${\AA}$ have been analyzed by the modified Wilson and Devinney light curve program. The radii of the B star and M star were deduced to 0.05 and 0.22 of unit separation, respectively. The UV light curves show an evidence that the light was attenuated by the highly opaque atmosphere of the M star.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 1992년도 한국우주과학회보 제1권1호
• /
• pp.14-14
• /
• 1992

The IUE archival spectra of VV Cephei were collected to investigate the eclipse nature in the ultraviolet. The temperature of the B star has been determined, as approximately30,OOOK, based en the flux distributions durstributions during egress, Light curves of VV Cephei were reduced from the spectrophotometry of the IUE archival spectra. Three light curves at the center wavelengths of 2350A,2550A and :!850A have been analyzed by the modified Wilson and Oevinney light curve program. the radii of the B star and M star were deduced to 0.05 and 0.22 of uint separation, respectively. The UV light curves show anevidence that the light was attenuated by the highly opaque atmosphere of the M star

• 대한지구과학교육학회지
• /
• 제4권1호
• /
• pp.32-42
• /
• 2011

The purpose of this study is to provide meaningful basic materials for organizing a science curriculum in future by analyzing the status and changes of contents about astronomical phenomena in textbooks according to the changes of the science curriculum of elementary school. A main target of analysis is science textbooks of elementary school in curriculums from 1st to 7th. For the analysis, the analytic frame based on contents in astronomy textbooks of teachers colleges and colleges of education was used. The result of the analysis is as in the following. First, astronomy accounted for average about 7% of all pages of textbooks in all of science curriculums. The 1st educational curriculum had the most learning quantity of 10.40%, and the 6th curriculum had the least quantity of 4.39%. These results show that astronomy was not a small part and was considered important in each science curriculum of elementary school considering that earth science accounted for 17-26% of all pages in elementary school science curriculum. Second, the things that have been dealt with in common in all science curriculums from 1st to 7th of elementary school are the shape of the earth, the rotation and the revolution of the earth, the occurrence of the seasons, the apparent motion of the sun, the status and motion of the moon, the movement of a star, the brightness and distance of a star, constellations, the sun, planets and others. These contents are expected to be dealt with continuously as basic contents to organize astronomy regardless of the changes of curriculum. Third, in science curriculum of elementary school, astronomical phenomena based on life experiences regarding the earth, the moon and the sun are mainly dealt with in the first and the second grade. Contents requiring principles-understanding and research are dealt with in the fifth and sixth grade. These results show that elementary school science curriculum dealing with astronomy reflects the developmental stages of students and considers principle of learning possibility.

• 천문학회지
• /
• 제2권1호
• /
• pp.33-39
• /
• 1969

The gain of internal energy of a star cluster caused by the tidal attraction of our Galaxy is examined. Expressions are derived which include the effects of a two-body orbit and internal motions of the cluster. These formulae are compared with previous results based on (i) uniform rectilinear motion and (ii) neglect of internal motions induced by cluster gravitation(i.e., impulsive approximation), and it is found that these simplifying assumptions generally introduce significant uncertainties.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
• /
• pp.694-697
• /
• 2005

A conceptual study about the angle information based orbit determination technique for a geostationary satellite was performed. With an assumption that the simultaneous observing of the earth and nearby stars is possible, we confirmed that the view angles between the earth and stars can be use as inputs for orbit determination process. By the MA TLAB simulation with least square method, the convergence is confirmed. This conceptual study was performed with the COMS for instance. This technique will be able to use as a back-up of ground station's orbit determination or a part of autonomous satellite operation.

• 한국지구과학회지
• /
• 제31권7호
• /
• pp.827-838
• /
• 2010

본 연구의 목적은 현직 초등학교 교사들의 천문학적 거리 개념을 확인하고 천문학적 거리에 대한 편차 규모와 천문학적 거리를 점점 확대 시켰을 때 정확성을 알아보기 위한 것이다. 경기도 소재 초등학교 교사 69명을 대상으로 천문학적 거리 관련 질문지를 배포하여 결과를 분석한 후 3명을 임의 추출하여 그들이 작성한 질문지를 바탕으로 인터뷰를 실시하여 그들의 천문학적 거리 개념을 분석하였다. 많은 초등학교 교사들이 지구와 달, 태양 사이의 거리를 과대 평가하였고, 항성 및 은하까지의 거리는 매우 과소평가하였으며, 천문학적 거리를 이론적(계산적) 척도와 직관적(심리적) 척도를 활용하여 추정하였다. 그들은 AU, 광년과 같은 단어를 익히 들어 잘 알고 있으나 그 의미를 정확하게 이해하지 못하는 사례도 있었으며, 지구에서 해왕성까지의 거리가 항성까지 거리 보다 더 멀다고 인식하는 사례도 있었다. 천문학적 거리를 추정할 때 상당한 변이성이 존재하며, 태양계 내에서 태양계 밖에 존재하는 천체로 거리를 늘려나갈수록 초등 교사들은 그 거리를 점점 더 과소평가하였다.