What is Declination: Definition and 28 Discussions

In astronomy, declination (abbreviated dec; symbol δ) is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the celestial equator, along the hour circle passing through the point in question.

The root of the word declination (Latin, declinatio) means "a bending away" or "a bending down". It comes from the same root as the words incline ("bend toward") and recline ("bend backward").In some 18th and 19th century astronomical texts, declination is given as North Pole Distance (N.P.D.), which is equivalent to 90 – (declination). For instance an object marked as declination −5 would have a NPD of 95, and a declination of −90 (the south celestial pole) would have a NPD of 180.

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  1. collinsmark

    Stargazing Fixing declination runaway on a Meade LX200 telescope

    Part I: Introduction to the problem. I made this thread to document and discuss the repairs I made to my 10" LX2000-ACF telescope to fix a declination runaway problem. It involves replacing an optical encoder attached to the declination/altitude motor. I expect this documentation will be broken...
  2. S

    I Confused about declination, elevation & altitude

    They seem to be similar terms, although elevation & altitude seem to be the exact same thing. AIUI, the declination of astronomical object refers to the latitude on Earth where it is at the celestial zenith - i.e., straight up, along the line from the Earth's center and surface at such zenith...
  3. U

    I Error in declination of linear regression

    During a lab exercise we measured different masses of a magnetic material on a scale while changing the strength of the magnetic field it was in. Afterwards we plotted the masses and the fieldstrength hoping to find a linear slope. Then we drew a linear slope by using linear regression and found...
  4. Jadaav

    I RA and declination of Sun & phase of Moon program

    Hello there, I want to write a fortran program which gives me the right ascension and declination of the sun and the phase of the moon when a date and time is given. I just want to know how to write it and if there are any references that can help me. Thanks, Jadaav.
  5. Philosophaie

    I The declination at the horizon in the east at a latitude

    I am trying to find the declination at the horizon in the east at a particular latitude. The equation is: delta = asin(sin(lat)*sin(Alt) - cos(lat)*cos(Alt)*cos(Azi)) where Azi is the azimuth and is equal to 90 degrees in the eastern most direction. Alt is the Altitude and is equal to 0...
  6. K

    I Different densities of the universe on different angles?

    Does anybody know of a resource that I could use to determine the density of the universe along a specific line of sight? (right ascension and declination)I am investigating inertial forces and looking to identify both the most and least dense directions in space and determine by how much they...
  7. Barely_Conscious

    I How would one know whether a star would be observable?

    I'd like to answer this yes or no question for a number of objects: "Is this star, at any point between these two times, going to be above the local horizon?". Say, I'm at the prime meridian at a latitude of 50 degrees, and I want to know whether, between the sidereal times of 11:00:00 and...
  8. F

    Astronomy: Sun azimuth from altitude, hour angle, and declination

    Homework Statement Hi everybody, I am trying to do a numerical aplication of change of coordinate system to another; the objective is to calculate the azimut of the sun knowing the altitude, hour angle and declination . Homework Equations Cosh * Sina = Cosδ * Sin H where a is the azimut h is...
  9. W

    How Much Declination Do Stars Need for a Luck City at Latitude 35°?

    People in the past thought that a city which the length of the visible arc of a star's path in that city is longer, that city is the luck city; Now, for a city with a latitude of 35° how much should be the star's declination to be the luck city?
  10. nicolauslamsiu

    Determine the least value of declination of stars so that stars can be seen?

    For stars to be observed in a certain place, the stars must be at a position above the horizon. Yet, how to determine the least value of declination of stars so that stars can be seen?
  11. R

    How can I determine right ascension and declination of a star in the sky?

    I have a location of approximately 35 deg 14' S and 149 deg 4' E, and I have measured the position of the star Antares to be at an altitude of 27 deg 00' using an inclinometer, and direction 247 deg using a compass. Using this information can I calculate the direction of the star on the...
  12. S

    Right Ascension and Declination

    Homework Statement Can someone help me to understand this problem: You observe an object at location(longitude –16°30’E, Latitude 28°18’N) passing the meridian (azimuth=0) at 5h (am) Coordination Universal Time (UCT). The star's elevation is 43°40’ and the stellar time at Greenwich at 0h...
  13. B

    How do you calculate declination and Right Ascension from Earth Coordinates?

    Say a person is positioned here: 40.23°N and 15.89°E and was examining the night sky. How do you calculate the declination and Right Ascension from that location's coordinates? I know the RA is measured in hours up to 24 and Declination in degrees. Any ideas?
  14. S

    How does declination and right ascension relate to latitude / longetude?

    It seems to me declination lines are vertical like longitude, and coordinates is measured horizontally (but if it runs vertical than how could it be measured as 0° at the equator?), and right ascension lines run horizontal like latitude with coordinates measured vertically. However this...
  15. D

    Failure to calculate equation of time and declination of the sun

    Calculating the equation of time and the declination of the sun Hi, I'm trying to calculate the equation of time and the declination of the sun in the prettiest way possible: https://gist.github.com/1278755" But right now I'm getting some unexpected values: 1) Failure...
  16. P

    Help me to get the names of all stars with their declination?

    I want to check circumpolar stars for the observer whose latitude is 26 degree 28 minute 12 second North (My office). From here, latitude = 26 degree 28 minute 12 second North, all stars with a declination higher than +63 degree 31 minute 48 second are such circumpolar stars. And stars with a...
  17. T

    Circumpolar star declination problem

    hi, heres' problem from an international olympiad "The Damavand Mountain is located at the North part of Iran, in south coast of Caspian Sea. Consider an observer standing on the Damavand mountaintop (latitude = 35° 57′ N; longitude = 52° 6' E; altitude 5.6 x 10^3m from the mean sea level)...
  18. T

    Circumpolar star declination problem

    The Damavand Mountain is located at the North part of Iran, in south coast of Caspian Sea. Consider an observer standing on the Damavand mountaintop (latitude = 35° 57′ N; longitude = 52° 6' E; altitude 5.6 x10^3m from the mean sea level) and looking at the sky over the Caspian Sea. What...
  19. Philosophaie

    Right Ascension and Declination to the Horizon

    Let's just say I was on a ship in the middle of the ocean. I am at a certain Longitude and Latitude with a Right Ascension (RA0) and Declination (DEC0) looking straight up into the heavens. If I look East how many degrees (RA and DEC) difference from my initial location to the horizon? Also...
  20. B

    Solar declination / solar panel array design

    I need some help, I am planning on installing a 10 kilowatt solar panel array in the next couple of months. I will not be using a solar tracking device. The plan thus far is to determine the solar south bearing and face the panels in that direction and work out an appropriate angle for the...
  21. Philosophaie

    Right Ascension and Declination

    How do you find Right Ascension and Declination from basic Keplerian data?
  22. J

    How do I map a celestial object's declination ?

    to my local meridian at various times of the year. An object's declination will be fixed - relatively speaking - but its altitude on my local horizon varies from season to season because of Earth's movement, doesn't it? Also, if I'm at a lat. 47.3 N shouldn't celestial objects w/dec. of -{90 -...
  23. A

    Declination and Right Ascention

    I have two questions I cannot figure out: How is declination measured in the celestial sphere, in comparison with how terrestrial latitude is measure on earth How is RA measured in the celestial sphere, in comparison with how terrestrial longitude is measure on earth. Thanks!
  24. M

    Answer: Declination of the Sun - Spring Equinox

    Hi, This might sound like a simple question, but it's not for me. I'm standing at the Tropic of Cancer - what would be the declination of the Sun on the Spring equinox. I believe it should be zero degrees, but my brother says it's 23.5 degrees. Can anybody shed light? Thanks in advance...
  25. I

    Satellite Right Acension and Declination Calculations

    Hi Everyone... I really want to be able to calculate the RA/DEC of a Satellite from TLE data. For example, the International Space Station (ISS) Can anyone help to point me in the direction of where to find the claculations I need to perform this conversion from TLE data to RA/DEC? I...
  26. C

    Graph Right Ascension & Declination on Globe Graph

    Can anyone explain how to graph Right Ascension and Declination on a globe graph?
  27. G

    (problem) Spherical trigonometry and star declination

    I am looking for a general approach for a type of problems as follows... Certain circumpolar star has a maximum azimuth A given for example as an angle from North to East and from North to West. Whats the declination of that star? The problem looks like this: draw a celestial sphere and...
  28. B

    Right Ascension and Declination

    Hi guys, This might be a stupid question and all, but I was wondering how would you know what Right Ascension and Declination coordinates are visible from a particular location? I mean I was having a look at an old almanac lying around here and couldn't really make sense of how you can see...
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