Questions tagged [positional-astronomy]

Questions about positions of objects in the sky, either relative to a fixed coordinate system like the equatorial and ecliptic coordinate systems, or relative to an observer's point of view.

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36 votes
2 answers
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Where can I find the positions of the planets, stars, moons, artificial satellites, etc. and visualize them?

What resources are available to find the positions of planets, stars, moons, artificial satellites, asteroids, and other heavenly bodies?
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9 votes
2 answers
392 views

Is it possible to figure out your location in the Milky Way if you are suddenly wormholed to a random, distant location in the galaxy?

If you were flying along in your spacecraft somewhere in our solar system and then a large, stable wormhole suddenly opened and you flew into it and were whisked away to some distant location in the ...
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  • 203
8 votes
4 answers
2k views

Generate a uniform distribution on the sky

How to generate a uniform distribution of stars on the sky ? What I want is make a simulation of random points following uniform distribution on a part of the sky (making the assuption that we have ...
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  • 301
8 votes
1 answer
3k views

What is the Galactic Latitude and Galactic Longitude? How is different from the latitude and longitude we use on Earth?

It has to something with the positioning of sun and galactic center of the milky way but I wasn't able to understand how for a given star, its co-ordinates are calculated. Some explanation would be ...
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5 votes
0 answers
198 views

Viewing "Diamond Fuji"

Diamond Fuji is a phenomenon in which the (typically) setting sun is positioned directly atop Mt Fuji. Some relatively detailed predictions for viewing times at a nearby park are available here. I ...
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  • 151
4 votes
1 answer
322 views

Stellarium simulation

I'm interested lately in Stellarium and the functionalities which it provides especially scripting. I want to make a simulation that shows the celestial sphere with some planets like Venus, Mars, and ...
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  • 141
30 votes
1 answer
4k views

If dark matter bends light, how do we know the stuff in the sky is where we think it is?

We measure movement, position, and many other things of an object in space because of its light and what we can measure with it. But as far as I know there's supposed to be a HUGE amount of dark ...
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7 votes
3 answers
786 views

How/where to check where the Sun is (constellation)?

I would like to check in which constellation the Sun was in at some time in the past, any recommendations how to do that?
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6 votes
1 answer
641 views

Planets positions (azimuth, altitude) API

I'm looking for a simple API that will allow me to get positions of planets and the moon for a given date, location and time. Does anyone know an API like that? Any suggestions or alternatives would ...
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5 votes
2 answers
383 views

Tips of Crescent

Can it be shown mathematically that the line connecting tips of crescent is parallel to the North-South line and the line gives latitude of the plane ( When the Moon is sufficiently close to the ...
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4 votes
3 answers
576 views

What are the correct positions or alignment of planets in relation to each other and the Sun, is it vertical center, baseline or completely random

From a lot a illustrations and videos, the planets seem to align in vertical center to each other like this: Is this really true? I like to imagine that the planets are actually in weird alignment to ...
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10 votes
2 answers
1k views

JPL Horizons - "highly accurate measurements of planetary positions" - how do they do it?

According to JPL Horizons, with regard to their planetary position calculations, ... we integrate the equations of motion in Cartesian coordinates ($x,y,z$), and we adjust the initial conditions in ...
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  • 559
2 votes
1 answer
92 views

About coordinate systems and angle differences

If I want to measure the beam-width of a radio telescope sweeping through a ~ puntual object (the Sun) with a ~ constant flux output when measured: The value measured sweeping in one frame of ...
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  • 525
2 votes
1 answer
136 views

Where can I get J2000 epoch initial mean longitudes for all planets and celestial bodies?

I'm following this paper to calculate geocentric coordinates. The authors have provided the initial mean longitude values for the planets (provided in attached table) for 01.01.2000 @ 00.00 UT but I'...
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2 votes
1 answer
685 views

Help with Converting Right Ascension and Declination into 3D Vectors

Using the Right Ascension and Declination values from the HYG Database from The Astronomy Nexus: Right ascension is measured in hours and declination is measured in degrees. 1 - Convert right ...
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  • 225
2 votes
1 answer
444 views

Jean Meeus - calculating moon rise, transit and set times - help isolating error in logic

I've been working my way through the Jean Meeus Astronomical Algorithms book for a few weeks, to implement some of the key algorithms for a personal project. This task has been a little more complex ...
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  • 21
2 votes
2 answers
147 views

The Jupiter Effect Book

This evening I have been thinking about the anxiety caused in 1982 by predictions in John Gribbin and Stephen Plagemann 1974 book The Jupiter Effect. I was a teenager in 1982. The planets aligning ...
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