天體觀測高度程式之開發

The Developed Program for Observed Altitude of Celestial Bodies

天體觀測高度是決定天文觀測船位的關鍵變數，而航海者一般都採用航海曆作為查表計算之工具。在人工查閱航海曆的過程中，存在著複雜、耗時與準確度受限等眾多缺失，然而在目前海事教育及海上實務作業裡，計算方法卻不是主要的求解方式，此引發本論文的研究動機。另外，發現在美國地理空間情報局的網站上，其程式缺乏完整性，而美國海軍所開發的STELLA軟體又不對外公開。針對上述缺憾，本論文採用MATLAB(上标 ®)程式語言中內建的使用者圖形介面成功地開發出天體觀測高度程式，此自行開發程式均透過例題確認無誤。

Navigators usually used the nautical almanac as a tool to obtain the observed altitude of celestial bodies, and it is a key variable to determine astronomical vessel position. It is known that several shortcomings have arisen in artificial process, such as complexity, time-consuming, and/or limited precision. However, computational approaches are not dominant solving tools in the currently maritime education or practical operation and thus, it leads to the motivation of this article. Besides, it is also found that the observed altitude program posed at NGA website is not complete and the U.S. Navy's STELLA software is not available to the public. Aimed at these drawbacks, the Graphical User Interface, built in the MATLAB(superscript ®) is adopted to develop the program, namely the ObsAlt, to obtain observed altitude of celestial bodies. This self-developed program is verified with several examples presented in artificial process.