![]() The altitudeĬorrection values strictly apply only in the case where the observations Obtain the altitude intercept in the usual way. Removing instrumental and dip (height of eye) corrections. The altitude corrections are intended for use during sight reduction.įor a given object, to obtain the observed altitude (Ho), the sum of theĪltitude corrections (in the rightmost column) is added to the apparentĪltitude (ha), which is itself obtained from the sextant altitude (hs) by Navigational stars are also shown in black. ) are shown in blue providing that their Hc values are between 15 andĦ5° otherwise they are shown in black. Data for the stars that are listed in Sight Reduction Tablesįor Air Navigation Vol. 1 (Selected Stars) ![]() The data are color-coded as follows: Data for solar system objectsĪre shown in red and always appear first in the The GHA of Aries is always shown at the end of the list of objects. Stars and data for objects that may be too close to the Sun for observation Whether observations of them are practical. 3° when data for the Moon is shown, a note on its phaseĭata are shown for objects above the horizon without regard to Almanac data for the Moon is shown if its Hc is greater than Twilight (this is intended as an aid in judging the brightness of the Shown if its Hc is greater than -12°, the limit for nautical Or to convert between Degrees-Minutes-Seconds (DMS) and Decimal Degrees.ĭata can be produced for any date and time from year 1800 through yearĭata are shown for the navigational stars and planets only if theirĬomputed geocentric altitude, Hc, is equal to or greater than Use the buttons under Location to find coordinates of cities or towns in the U.S. Position you provide without any table lookup. The coordinate values, since all data is computed specifically for the exact Of your actual location (e.g., your DR position) there is no need to round The assumed position that you enter below can be your best estimate ![]() It is assumed that the center of light is observed. The SD values are non-zero only for the Sun and Moon for all other objects, Semidiameter (SD), parallax in altitude (PA), and the sum of the altitude corrections The altitude corrections consist of atmospheric refraction (Refr), The almanac data consist of Greenwich hour angle (GHA),ĭeclination (Dec), computed altitude (Hc), and computed azimuth (Zn). The output table gives both almanac data andĪltitude corrections for each celestial body that is above the horizonĪt the place and time that you specify. Simply fill in the form below and click on the "Get Data" Plot navigational lines of position from observations of the altitudes of celestialīodies. This data service provides all the astronomical information necessary to Celestial Navigation Data for Assumed Position and TimeĬelestial Navigation Data for Assumed Position and Time.Earth's Seasons - Equinoxes, Solstices, Perihelion, and Aphelion.Topocentric Positions of Major Solar System Objects and Bright Stars.Geocentric Positions of Major Solar System Objects and Bright Stars.Topocentric Configuration of Major Solar System Bodies.Altitude and Azimuth of the Sun or Moon During One Day.Positions of Selected Celestial Objects.Duration of Daylight and Darkness Table for One Year.Rise/Set/Transit Times for Major Solar System Objects and Bright Stars.Table of Sunrise/Sunset, Moonrise/Moonset, or Twilight Times for an Entire Year.
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