Right ascention/arc-second

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In summary, the conversation is about understanding celestial coordinates and measurements. The first question asks about the location of right ascension zero in the sky, in relation to the ecliptic or constellation. The second question is about comparing arc-seconds to arc-minutes and degrees. The person responding suggests using Google to research and understand these concepts rather than simply asking for the answers.
  • #1
chill85
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1. Where in the sky is the right ascention equal to zero?(in terms of the ecliptic/constellation)
2. How does an arc-second compare to an arc-minute and a degree?
 
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  • #2
This sounds like homework questions. If you will Google on the terms you are using, you will find a lot of information on your own. Then post again if there are some things that are unclear. The Internet is a great reference resource, but you have to use it as such instead of asking for the answers. If you get an answer, and pass it in as your own work without understanding it, you're short-changing yourself.
 
  • #3


1. The right ascension of zero can be found at the vernal equinox, which is the point on the celestial sphere where the ecliptic (the apparent path of the Sun) intersects with the celestial equator. This point is currently in the constellation Pisces, but due to the precession of the Earth's axis, it moves through different constellations over long periods of time.

2. An arc-second is a unit of angular measurement equal to 1/60th of an arc-minute and 1/3600th of a degree. In other words, there are 60 arc-seconds in an arc-minute and 3600 arc-seconds in a degree. This means that an arc-second is a much smaller unit of measurement compared to an arc-minute and a degree. To put it in perspective, the width of a human hair at arm's length is roughly 1 arc-minute, while the width of a grain of sand at arm's length is roughly 1 arc-second.
 

1. What is right ascension?

Right ascension is a celestial coordinate used in astronomy to measure the east-west position of a celestial object. It is similar to longitude on Earth and is measured in hours, minutes, and seconds.

2. How is right ascension different from declination?

While right ascension measures an object's position along the celestial equator, declination measures its position north or south of the celestial equator. Together, they give the exact location of a celestial object in the sky.

3. What is the unit of measurement for right ascension?

The unit of measurement for right ascension is hours, minutes, and seconds, denoted by "h", "m", and "s" respectively. This unit is based on the Earth's rotation and represents the amount of time it takes for a celestial object to cross a specific point in the sky.

4. How is right ascension related to arcseconds?

Right ascension can also be measured in arcseconds, which are smaller units of angular measurement. One hour of right ascension is equivalent to 15 degrees, and one degree is equal to 60 arcminutes or 3600 arcseconds.

5. Why is right ascension important in astronomy?

Right ascension, along with declination, is an essential coordinate in astronomy as it helps astronomers locate and track celestial objects in the sky. It is also used in celestial navigation and timekeeping systems.

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