What is the Angular Extent of Trigonometric Parallax?

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In summary: Angular extent and trigonometric parallax are both ways to measure an object's size, but they use different methods. Angular extent is simply the angular size of an object, while trigonometric parallax uses the Earth's orbit as a baseline to determine an object's distance and size. So, in summary, angular extent and trigonometric parallax are different ways of measuring an object's size, with angular extent being based on its angular size and trigonometric parallax using the Earth's orbit as a baseline.
  • #1
mahsa
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Hi
I know the meaning of trigonometric parallax, but what is angular extent?
In a problem, it is stated that the true angular extent of semi major axis of the orbit is 7.61".
Is it different from parallax?
Thanks
 
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  • #2
The angular extent is simply the angular size---i.e. how big it looks.
 
  • #3
mahsa said:
Hi
I know the meaning of trigonometric parallax, but what is angular extent?
In a problem, it is stated that the true angular extent of semi major axis of the orbit is 7.61".
Is it different from parallax?
Thanks
the typical application of parallax is where the baseline is provided by OUR orbit around the sun.

It sounds to me as if you have a school problem in which there is a binary star or the star has a planet or something orbiting it.

So you are supposed to estimate the real size of a distant object (an orbit) given its angular size seen from earth.

the picture is turned around, the base of the long skinny triangle is out there.

With parallax the baseline is here at home. We get to look at the object from two different locations along the Earth's orbit.

That seems like a difference.
 
  • #4
Thank you very much! I got it.
so, if I know the distance to that binary or orbit, I know its linear size.
 
  • #5
mahsa said:
Thank you very much! I got it.
so, if I know the distance to that binary or orbit, I know its linear size.

Yes!
 

1. What is the definition of angular extent?

The angular extent is a measure of the size or width of an object or phenomenon as seen from a specific point of view, typically expressed in degrees or radians.

2. How is angular extent different from linear extent?

Angular extent refers to the apparent size of an object, while linear extent refers to its actual physical size. Angular extent takes into account the distance between the viewer and the object, while linear extent does not.

3. Can angular extent be negative?

No, angular extent cannot be negative. It is always a positive value, as it represents the angle formed by the two lines connecting the viewer to the two endpoints of the object.

4. How is angular extent measured?

Angular extent is typically measured in either degrees or radians. Degrees are a more common unit of measurement, with a full circle being equal to 360 degrees. Radians are a unit of angular measurement based on the radius of a circle, with a full circle being equal to 2π radians.

5. What factors can affect the angular extent of an object?

The angular extent of an object can be affected by the distance between the viewer and the object, the shape and size of the object, and the angle at which it is viewed. Other factors such as atmospheric conditions or obstructions in the line of sight may also affect the perceived angular extent of an object.

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