Questions tagged [coordinate]

Questions on systems to uniquely determine position of a point or other geometric element on a manifold such as Euclidean space.

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Where is it possible to observe the Moon for 24 hours?

I wrote an astronomy olympiad yesterday and there was one task I couldn't figure out an answer to: Estimate at what latitudes it is possible to observe the Moon for at least 24 hours. Under what ...
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2answers
69 views

Mathematics for Conversion between ICRS and AltAz

I am writing some software, for my own learning experience, to convert astronomical coordinates to different frames of reference. An example of this would be conversion between ICRS which a lot of ...
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1answer
49 views

At what time of the day of autumnal equinox the Sun's equatorial coordinates reach max value?

I'm trying to solve this task: At what point in time of autumnal equinox day, at sunrise or sunset will a) the declination of the Sun b) the right ascension of the Sun reach the maximum value? I'm ...
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1answer
66 views

Altitude of Polaris is latitude

How to prove geometrically that the altitude of Polaris is equal to the latitude? I have seen in handouts that the altitude of the pole star gives the latitude of that place.
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48 views

What is the Sun's absolute direction called?

Like the Sun's direction relative to the local standard of rest is called "solar apex" What term can I google instead to find info about the Sun's direction relative to the CBBR? I ...
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2answers
42 views

Given a location and a time on another planet, how do you determine how many hours before or after sunrise is it there?

I'm actually not so much interested in sunrise/sunset times. What I want to know is how to relate local planetary coordinates (e.g., planetary lat/lon) to, for example, heliocentric coordinates at a ...
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2answers
127 views

How come I can point to two places with telescope and have the same coordinates?

Absolute beginner here. I read through the telescope manual, watched many videos, and got a pretty decent understanding of DEC and R.A. However, I don't understand one thing (where theory doesn't ...
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0answers
31 views

How does the rock Simurgh Saxum (-25.32°, 4.05°) on 101955 Bennu define its prime meridian and serve as the basis for its coordinate system?

Spaceref's NASA's "Tour of Asteroid Bennu" Selected for Prestigious Computer Graphics Film Festival says: It's hard to imagine what the surface of asteroid Bennu might look like - it's ...
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1answer
118 views

Understanding the constant 6.697374558 when finding GMST

I'm trying to understand the constant 6.697374558 mentioned in this question: The Astronomical Almanac gives an expression for approximate mean sidereal time, in hours: $$\mathit{GMST}=6.697374558+0....
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1answer
526 views

Conventional units for astronomical object coordinates

I would like to know what the conventional units for identifying a celestial object (J2000.0) are. For instance, I am reading a paper in which they refer to object SDSSJ170013.70+400855.6; I am ...
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1answer
66 views

What are the aspects does the moon differs between cities located on the same latitude?

What are the aspects does the moon (astronomical position and other astronomical aspects) differs between cities located in the same latitude? - For example: Seattle, Munich, Vienna, and Ulaanbaator ...
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2answers
193 views

If I was in a coma and woke up at night in the desert, what knowledge would I know instantly and after 30 days?

If I was in a coma and woke up at night in the desert, what knowledge would I know instantly and after 30 days of observation? Can I figure out the general directions, i.e. where North, South, East, ...
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1answer
74 views

Understanding the difference between local time and local sidereal time

I am currently attempting to understand different systems of telling the time: particularly, distinguishing local time (LT) from local sidereal time (LST). I understand that they often differ; despite ...
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1answer
49 views

What do these latitudinal and longitudinal lines and accompanying hours and degrees represent?

I'm a beginner in Astronomy. What do these latitudinal and longitudinal lines and accompanying hours and degrees represent (in blue: +12h , +11h.. and +45° +60°.. , in orange: +330° , +15°) ?
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rotate right ascension, declination based on delta time

Assuming I was observing a source at a given right ascension $\alpha_0$ declination $\delta_0$ at a given time $t_0$ under a certain azimuth $A$ and elevation $a$ angle. If I now change my time to $...
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2answers
107 views

Conversion of Moon's Celestial Position (RA and dec) to Horizontal Coordinates [closed]

I'm currently attempting to calculate the equatorial sky position of the Moon for any given Geostatic position (longitude / latitude) for any given datetime. I have tested my altitude and azimuth ...
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1answer
340 views

Can someone explain to me the TEME reference frame in defining orbital coordinates?

I am undertaking a project of developing a "surface station" for my desktop, which will track the position of different satellites as they fly overhead. I have zero background in ...
3
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1answer
150 views

Is this how stars’ right ascensions correlate to planets’ longitudes on a 2d map?

This is my first ever online question, so please bear with me: I’m working on an A1-sized map of at least 100 of the largest solar system bodies (henceforth just called ‘planets’, ignorning the IAU ...
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0answers
23 views

Filtering local region in SIMBAD

I am completely new to astrophysics and currently writing a paper on Cepheid variables for high school physics. I would like to filter out all Cepheid variables in the local system which I would ...
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0answers
35 views

Converting Invariable plane to J2000 ecliptic

I've been following the answer given by Mike G here: How to calculate the orientation of planets at current epoch to get planets to have the correct orientation in my program, but all the angles are ...
5
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1answer
531 views

Coordinates in the Night Sky

I've learned about Orbits recently, and there are 6 orbital elements. Now, I've heard of three coordinate systems whereas, they can help you measure positions of stars in the night sky. The Altazimuth,...
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1answer
70 views

What is a "fundamental location", and why is Mosting A defined as one for the moon?

The crater Mosting A was chosen to be the "fundamental location" for the Moon's coordinate system (latitude and longitude). But what exactly is a "fundamental location"? What does ...
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What do these coordinates mean: MW - VP101 3° 12' 43.2'' S 5° 12' 39.6'' W?

I have a jacket with a tag that bears the label: MW - VP101 3° 12' 43.2'' S 5° 12' 39.6'' W When I looked it up, I discovered that these are the coordinates of the ...
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2answers
65 views

Plotting Equatorial coordinates to X,Y plane (simulating telescope/camera view)

I would like to simulate a telescope camera view, projecting (RA, Dec) coordinate sets to a 2D plane. So effectively the need is to convert Equatorial coordinates to (x, y) coordinates, when we can ...
3
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1answer
53 views

What is the longitude of the winter solstice for the various planets?

I am looking for data showing the longitude at which the various planets in the solar system reach their winter solstice. Where could I find this data?
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1answer
60 views

Orbit of Luhman 16?

I am studying some binary stars and brown dwarfs. Some orbits are known and easy to find, like Alpha Centauri. However, when I look for the orbital characteristics of Luhman 16 (AB), I only get the ...
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57 views

How to calculate longitude of Alcyone - η Tauri in the year 41050 BCE?

Using the following information from The Skylive, and simple arithmetic I tried to calculate longitude of Alcyone in the year 41050 BCE at a place: 29.9457 N , 78.1642 E. Galactic Longitude 166.67°, ...
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2answers
166 views

Solar Azimuth angle Derivation

I tried posting this on math stack exchange to no avail so I thought maybe it's more relevant here : I know a similar question has been posted here before but no links to any mathematical derivations ...
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0answers
59 views

How is the incidence angle of the Sun related to the lean angle of the Cooks pines?

Auracaria columnaris (Cooks pine) on average lean towards the equator. Most of the pines in the Northern Hemisphere lean southward and most of the pines in the Southern Hemisphere lean northward. ...
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50 views

Getting XYZ coordinates of Luminous Red Galaxies catalogue

So I want to get the XYZ (rectangular/Cartesian) coordinates of the LRG (luminous red galaxies) catalog. The catalog is available for download from here: https://data.sdss.org/sas/dr16/eboss/lss/...
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1answer
81 views

Converting equatorial coordinates to Cartesian coordinates for extragalactic distances

I'm trying to search for galaxy clusters with the friends-of-friends (FoF) algorithm. I have the equatorial coordinates ($\alpha, \delta$) and redshifts ($0.5<z<2.5$) of galaxies that I wish to ...
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136 views

Time evolution data of the Great Red Spot on Jupiter?

Jupiter's Great Red Spot fascinates scientists for ages, so it does me. Where can I find a table (e.g. as CSV-file) with the time evolution of longitude, latitude, horizontal and vertical extension of ...
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2answers
77 views

When (yyyy-mm-dd) does the north pole of uranus most nearly point towards the sun?

When (yyyy-mm-dd) does the north pole of uranus most nearly point towards the sun? The information I've found suggests this happened in 1944 or 1945, but would like to find a more precise date or ...
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0answers
42 views

Calculate Global (ECEF) coordinates of Observer

I have the local coordinates of satellite and global coordinates of satellites. I want to calculate the observer position in global (ECEF) system. How can I do this? I also explain this question with ...
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1answer
44 views

Third rotational angle in equatorial coordinates

Right ascension and declination identify an object's position in the sky, but if we are looking at something through a telescope, there is a third angle of interest, namely how our view is rotated ...
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0answers
33 views

What are Native coordinates in the World Coordinate System?

i am writing my first paper about our solar telescope, and i need to explain the optical transformations in terms of World Coordinate Systems. I am not sure if i got the following right, and would be ...
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0answers
117 views

Clarifications about distances in cosmology

I would like to get clarifications about some usual notions of distances in cosmology. First, is the comoving distance the current distance of objects whose light has been reached by us now, i.e. ...
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2answers
228 views

How to calculate geocentric transformation to heliocentric coordinates?

I have Sun data (lon+lat+distance) in geocentric coordinates: but I want to visualize in heliocentric way. How to calculate that?
3
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1answer
599 views

How to plot celestial equator in galactic coordinates? Why does my plot appear "backwards"? [duplicate]

I'm trying to plot celestial equator in galactic coordinates. Here is my code (based on this answer): ...
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1answer
46 views

What is a UBV source for stars or stellar objects?

I was using the V19(VizieR) catalog and the main identifier of the stars was in terms of an 'ID' number which they mentioned as being 'Star number in UBV source' I have no idea what that means. How ...
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2answers
329 views

Data to "check" Kepler’s first law

I want to "check" Kepler’s first law by using real data of Mars. From the equation of the ellipse, I derived $$\frac{1}{r}=\frac{a}{b^2}+\frac{a}{b^2}\cdot\epsilon\cdot\cos(\varphi),$$ where ...
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0answers
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Data for "milky way outline" [duplicate]

I am trying to make a software generated star chart, and want to include the outline of the milky way as shown in many such star charts. Does anyone have any idea where to obtain the data for that? ...
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1answer
91 views

Figure out the location of celestial objects relative to the Milky Way in x, y, z co-ordinates

I am trying to place various celestial objects the correct distance from the Milky Way, using x, y, z co-ordinates. So assuming the centre-of-mass of the Milky Way is at 0, 0, 0 - how can I figure out ...
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1answer
40 views

Why does M101 search string have RA variable from 0 to 360 and Dec variable from -90 to +90 in the Hubble Legacy Archive?

I was scraping some images off the Hubble Legacy Archive and I found that searching M101 with RA in range 0-360 and Dec in range -90 to +90 yields results. Now I understand that Messier 101 galaxy has ...
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2answers
187 views

Is the "mean orbit" centered on ellipse center or ellipse focus?

Mean longitude and mean anomaly of a body are calculated as the angle covered by the body along a fictious circular orbit, and this is ok. But where is this orbit centered? Five different sources say ...
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1answer
314 views

What is the difference between azimuth angle and hour angle?

What is the difference between an hour angle and an azimuth angle? When I see illustrations of the two, the angles look very similar.
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2answers
74 views

Ecliptic coordinate ranges in radians

In ecliptic coordinates, what are the ranges of ecliptic longitude and latitude in radians? Do they both go from $-\pi$ to $\pi$?
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0answers
33 views

Using altitude, azimuth to determine a baseline vector?

I know the equatorial coordinates of a “beam” pointing from an Earth-based observer toward some distant star. I have converted those coordinates to altazimuth coordinates for that observer and a ...
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1answer
154 views

Horizontal to Equatorial Conversion - Code

Following this tutorial I have been able to convert from Equatorial to Horizontal Coordinates and am now searching for a way to do the reverse. I understand this kind of question has been asked and ...
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1answer
190 views

Calculation to Convert from Equatorial to Heliocentric coordinate systems

Can anyone help me with the formulas to convert Equatorial coordinates (Right Ascension / Declination) into Heliocentric coordinates (Angle and Distance in relation to the Sun) ? i.e. Ra/Dec of 6.7659/...

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