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Questions tagged [parallax]

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Why do we have to wait half a year to measure stellar parallax

To measure distance of astronomical objects, often we may use parallax, the angle it makes with the earth-sun and trigonometry to determine the distance. The thing I don't get is why do we need to ...
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How accurately can the distance of a star be measured?

With the launch of the GAIA mission some years ago, a new precedent was set in mankind's ability to map our universe. However, how accurate are the distances created by this? From ESA's website, I ...
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What is the simplest way to find the distance of stars?

Once, I was staring at the sky and wanted to know the distance to stars I could see. I searched the Internet but didn't find any easy to use tools. The distance to stars can be measured using ...
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Parallax versus Redshift when measuring astronomical distances?

From my understanding, the most common method for calculating how far away stars and galaxies are relative to us is by accounting for their redshift. I feel that this method could be inaccurate, ...
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How to use parallax and Cepheids together to measure distances?

I can't quite grasp the simple version of how the Cepheid method uses the parallax method to measure the distance to distant galaxies. What I know is that Cepheids exhibit a period vs luminosity ...
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Parallax calculation

I am asked to find the parallax of a star "Spica" as observed at $30.1$ $AU$ from the Sun. I want to use the small-angle formula: $\alpha=\frac{206265*D}{d}$ where $D$ is the baseline, $d$ the ...
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Negative Parallax

I am constructing a Hertzsprung-Russel diagram for stars within a radius around Pleiades and have repeatedly come across stars that have negative parallaxes. For example, http://vizier.u-strasbg.fr/...
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How to account for the movement of stars during measurement of parallax?

In my GCSE physics class today I was doing revision for my upcoming GCSEs, and we came to parallax measurements, as before my teacher explained that two measurements are taken six months apart as the ...
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3D movie optics mathematics

I get the idea that we use two polarized light sources and a parallax rendered film such that the objects seem to resemble true parallax in our eyes once it passes through the polarized glasses, but I'...
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Describe a path that a star moves around the sky [closed]

Suppose a star in the ecliptic plane has a parallax of p = 0.5 arcsec and a proper motion perpendicular to the ecliptic plane of µ = 1.0 arcsec/year. I need to describe the path that the star ...
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Measuring parallaxes from the moon

If one were to measure star parallaxes from the moon, what (if any) changes would you have to make compared to someone making the calculation from earth? What about on another planet in our solar ...
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Quick question on astronomical units

I'm trying to solve for $\frac{M*}{M_0}$ and $p''$ using these two equations: Here is the lecturer's working, I worked it out several times and I got a different answer! Surely when you use Kepler's ...
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Quick question on parallax and parsec

I know that 1 parsec (pc) is the distance of star at which 1 AU subtends 1 arcsecond. so $1 pc = \frac{1 AU}{1"}$ Now, if two stars in a binary with a separation of 3" and have a trigonometric ...
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How to calculate error of parallax and sextant based navigation?

First of all, why wasn't the sextant ever used for land navigation? The horizon is easier to see at sea, but land based sextants could be used in conjunction with artificial horizons (as at sea when ...
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Parallax, obliquity, precession, and Orion?

Today, the obliquity of the earth is about 23.4°. 6500 years ago, it was about 24.1° Imagine the blue square is the constellation of Orion, and the yellow star is the sun. Viewpoint B is you, on ...
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Parallax barrier to achieve “dual displays”

I am curious as to whether or not parallax barrier could be used to create the illusion that a screen is bigger than its physical dimensions. I assume this would only work in one dimension (width?). ...
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Other than the motion of the Earth, what else would cause parallax?

Wikipedia has this to say about the discovery of the aberration of light: In 1728, while unsuccessfully attempting to measure the parallax of Eltanin, James Bradley discovered the aberration of ...
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Why don't the relative positions of stars and other objects in a galaxy change over the year?

Though the identifiable stars in a constellation (say Andromeda) and a galaxy (say the Andromeda galaxy) are situated light years apart, why doesn't the galaxy appear at different positions with ...
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When and how were relative distances to the planets first measured?

I understand that the absolute distance to a planet can be measured using earth-baseline (e.g., diurnal) parallax, and that the first reasonably accurate such measurement was made for Mars by Cassini (...