Celestial navigation

Astronavigation:the ancient art and science of position fixing Created by:

Student of IAN 409Anastasiia KovalovaKiev-2015

PRELIMINARY CONSIDERATI

ONSThe science of Astronomy studies the positions and motions of celestial bodies and seeks to understand and explain their physical properties.

Navigational astronomy deals with their coordinates, time, and motions.

Celestial navigation - a set of methods for the determination of navigation parameters of the object, based on the use of electromagnetic radiation of astronomical objects.

It is used to determine the course and navigational coordinates at ground targets, as well as to determine the orientation of the aircraft.

Solar and Sidereal DaysDAY-TO-DAY CHANGES

Typical Night SkySEASONAL CHANGES

The Zodiac 

Nor

th P

olar

C

onst

ella

tion

sCamelopardusCassiopeiaCepheusDracoUrsa MajorUrsa Minor

Sout

h Po

lar

Con

stel

lati

onsPavo

Triangulum AustraleTucanaVolans

HydrusMensaMuscaNormaOctans

ApusChamaeleonCircinusCruxDorado

— that half of the Earth which is east of the 0° line of longitude (Greenwich Meridian). 

Eastern Hemisphere — that half of the Earth which is west of the 0° line of longitude (Greenwich Meridian).

Western Hemisphere

 North of the EquatorThe 88 constellations :42 animals, 29 inanimate objects,17 humans or mythological characters. 

South of the Equator

The scheme of finding of navigation stars in The Southern Hemisphere

The scheme of finding of navigation stars in The Northern Hemisphere

Celestial coordinate system

 The system for specifying positions of celestial objects: satellites, planets, stars, galaxies, and so on. Coordinate systems can specify a position in 3-dimensional space, or merely the direction of the object on the celestial sphere, if its distance is not known or not important.

(Orientation of astronomical coordinates)

 Coordinate systems:1.1 Horizontal system1.2 Equatorial system1.3 Ecliptic system1.4 Galactic system1.5 Supergalactic system

Practical Navigational InstrumentsPhotoelectric servo systems (Photoelectric magnitude) (The Yearbook of Aviation Astronomy)

Modern automatic astronomical instruments:Photometers

(Visual magnitude)

THE PROBLEM OF daytime invisible of luminaries :To address the daily visibility of stars can be used difference maxima of radiation spectra of the stars and the Earth's atmosphere.

With an increase in the wavelength of the radiation intensity of the atmosphere decreases rapidly. At the same time the radiation spectra a fairly large number of stars have a significant long-wave, infrared component.

The use of servo devices, photocells that are sensitive to infrared rays, and optical filters that absorb blue rays will allow to allocate these "infra-red" stars and watch them sustainably in a day flight.

Radio sextant(radio signals magnitude of celestial bodies)

TELEVISION AND RADIOLOGICAL DF SYSTEM

The image forming areas of starry skyThe determining the position of the horizon lineThe DF of luminaries

Astrolabe  Is a very ancient astronomical computer for solving problems relating to time and the position of the Sun and stars in the sky. 

to show how the sky looks at a specific place at a given time;

done by drawing the sky on the face of the astrolabe and marking it so positions in the sky are easy to find;

 locating and predicting the positions of the Sun, Moon, planets, and stars;

 the astrolabe and the mariner's astrolabe:

 for determining latitude on land; for use on the heaving deck of a ship or in wind.

 "star-taker"

Rising Sign is in 14 Degrees Sagittarius

Sun is in 25 Degrees Libra. 

Moon is in 07 Degrees Capricorn. 

Mercury is in 08 Degrees Libra. 

Venus is in 09 Degrees Virgo. 

Mars is in 15 Degrees Virgo. 

Jupiter is in 14 Degrees Virgo. 

Saturn is in 02 Degrees Sagittarius. 

Uranus is in 18 Degrees Aries. 

Neptune is in 07 Degrees Pisces. 

Pluto is in 13 Degrees Capricorn. 

N. Node is in 00 Degrees Libra. 

Sextant  The doubly reflecting navigation instrument used

to measure the angle between any two visible objects.

The sextant makes use of two mirrors. Mirror A is half-silvered, which allows some light to

pass through. In navigating, you look at the horizon

through this mirror. Mirror B in the diagram is attached to a movable

arm. Light from an object (the sun), reflects off this

mirror. The arm can be moved to a position where the

sun's reflection off the mirror also reflects off mirror A and through the eyepiece.

What you see when this happens is one object (the sun) superimposed on the other (the horizon).

The angle between the two objects is then read off the scale.

What makes sextant impractical for modern air travel ?

Are sextants could be found in any cockpits today?

Can a sextant be used while?

Astrocompass  Navigational instrument for giving directional bearings from the centre of the earth to a

particular star. ~Can predict true north rather than magnetic north.

~The use of astrocompass in determining the exact direction of true north requires the accurate information of time, date, longitudinal and latitudinal location.

The operation is as follows:Getting the local time (by

means of a clock)Setting the latitudeSetting (in the alidade) the

star's local hour angle (LHA) for that day obtained by means of tables or a computer program

Pointing the compass pinnula to the star (sun or moon)

Reading the true course on the limb

OctantReflecting quadrant- the instrument's arc is one eighth of a circle;-reflecting quadrant derives from the instrument using mirrors to reflect the path of light to the observer and doubles the angle measured;

Judith Moulton WallaceCelestial Navigation Instuctor

Using a marine sextant to measure the altitude

of the sun above the horizon

The bubble octantFrom the early 1930s through the end of the 1950s, several types of civilian and military bubble octant instruments were produced for use aboard aircraft.

The sight was easy to align because the

horizon and the star seem to move

together as the ship pitched and rolled

Satellite Navigation - GPS - How It Works

Aviators needed faster, more accurate, and more reliable navigation.

It does nothing more than simply receives signals.It's the applied technology that gives GPSits

versatility.Aviation GPS units are sophisticated and

specialized. 

The principles involved are the same as any standard system but the software is much more highly developed.

The GPS constellation consists of 24 non-geosynchronous satellites and is designed so that a minimum of five are always in view by a user anywhere on Earth.

 Three satellites provide the intersection point and the fourth is used to check that the positioning is accurate.

.

The GPS receiver needs at least four satellites to give a three-dimensional position (latitude,

longitude, and altitude). The GPS software interprets the signal, identifying the satellite that it came from, where it was

located, and the time that it took for the signal to reach the system.

Thank you for attention!