Horizontal + Celestial Coordinates to Geographic Coordinates

In summary: LongitudeWest = Right Ascension - (LMST + 15*(hour + min/60 + sec/3600 - TimezoneWest - dst))where hour, min, and sec are in local timeTimezoneWest (Western = +5) where West is positivedst = 1 for Daylight Savings Time and dst = 0 for notIn summary, the conversation discusses the possibility of calculating geographic coordinates on Earth using horizontal and celestial coordinates of a celestial body, along with the date, time, and other factors. The process involves calculating Right Ascension, Declination, Hour Angle, and other variables, and may require some effort to understand. It is recommended to consult resources on celestial navigation for a better understanding.
  • #1
Weskhan
4
0
Hey everyone,

I cannot seem to figure this out and I'm having a hard time finding any guides online for this stuff. All I can find are calculators. I was wondering if it would be possible to calculate my Geographic Coordinates on Earth if I had the Horizontal and Celestial coordinates of a celestial body as well as the date, time, etc. Could anybody give me hints on this? I've been trying to figure it out for awhile.

Thank you!
 
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  • #2
Well you have Right Ascension and Declination which are Celestial Coordinates.

They are fixed in the Sky.

Right Ascension is a product of: Local Sidereal Time + 15*(hour + min/60 + sec/3600 - Timezone - dst) + Longitude.

Local Sidereal Time is the distance in degrees from the Vernal Equinox.

DST is Daylight Savings Time 1 for on and 0 for off.

Declination is just the Latitude.

Hour Angle = Local Sidereal Time - Right Ascension

From Hour Angle, Latitude and Declination you find Azimuth and Altitude or Horizontal Coordinates.
 
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  • #3
I can recommend "Practical Astronomy with your Calculator" by Peter Duffet-Smith. You should be able to find a copy in your local library or, if you know how to use google, on the net.
 
  • #4
Thanks guys, I'll check out the book. Philosophaie I think you misunderstood. I am looking for calculate MY Geographical coordinates (longitude and latitude) from KNOWING the Celestial coordinates (right ascension, declination) of a celestial body AND the Horizontal coordinates of that body (azimuth, angle). I can't figure out how to reverse the calculations. :(

But thanks!
 
  • #5
I couldn't figure it out :( I have very very little experience with Astronomy. Is there anyone who could maybe help me out a little more? Thanks...
 
  • #6
Latitude = Declination.

LongitudeEast = Right Ascension - (Sidereal Time + 15*(hour + min/60 + sec/3600 - TimezoneEast - dst) ).

where hour, min and sec are in local time.

TimezoneEast (Eastern=-5) where East is positive.

dst =1 for Daylight Savings Time and dst = 0 for not.

Sidereal Time is LMST = (18.697374558 + 24.0657098244191 * d) + LongitudeEast
where d = JulianDate-2451545

Do the math.
 
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  • #7
I kind of missed that you wanted to calculate latitude and longitude from azimuth and elevation of a known star at a known time, and the other way around.

What you ask for is in general and in practice a bit more complicated to perform than the reference I suggested can hope to explain. Perhaps you can search for "celestial navigation" and "sight reduction"? It seems there are some good site that tries to explain this, like for instance [1], but as the subject is involved it may require some effort on your part. If you want a more simple approach you can perhaps follow the guide at [2].[1] http://www.celnav.de/
[2] http://www.eaae-astronomy.org/WG3-SS/WorkShops/LongLatOneStar.html
 
  • #8
Note: LMST = 15* (18.697374558 + 24.0657098244191 * d) - LongitudeEast where d is the time in days since 1-1-2000 @00:00:00 and LongitudeEast is in Degrees.
 
  • #9
Declination is only equal to Latitude when Azimuth = 0 and Altitude = 90deg or straight up. Other than up:

Declination = asin(sin(Lat)*sin(Alt) - cos(Lat)*cos(Alt)*cos(Azi)
 

1. What is the difference between horizontal and celestial coordinates?

Horizontal coordinates are a way of locating objects in the sky relative to the observer's position on Earth, while celestial coordinates are a way of locating objects in the sky relative to the celestial sphere. The celestial sphere is an imaginary sphere surrounding Earth, with the Earth at its center and the stars fixed on its surface.

2. How are horizontal coordinates represented?

Horizontal coordinates are usually represented by two values: altitude and azimuth. Altitude is the angle above the horizon, and azimuth is the angle measured clockwise from north.

3. What are geographic coordinates?

Geographic coordinates are a way of locating a point on Earth's surface using latitude and longitude. Latitude measures the distance north or south of the equator, while longitude measures the distance east or west of the prime meridian.

4. How do you convert horizontal and celestial coordinates to geographic coordinates?

To convert from horizontal and celestial coordinates to geographic coordinates, you will need to know your location on Earth and the time of observation. Using this information, you can use a mathematical formula or software program to calculate the corresponding latitude and longitude.

5. Why is it important to convert between different coordinate systems?

Converting between different coordinate systems allows us to accurately locate objects in the sky and on Earth's surface. It also allows us to compare data from different sources and make connections between different areas of study, such as astronomy and geography.

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