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Parallax Formula:
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Parallax is the apparent shift in position of a nearby star against the background of distant objects when viewed from different positions. Astronomers use this effect to measure distances to stars.
The calculator uses the parallax formula:
Where:
Explanation: The parallax angle (in arcseconds) is inversely proportional to the distance (in parsecs). One parsec is defined as the distance at which an object has a parallax of one arcsecond.
Details: Parallax is a fundamental method for measuring astronomical distances. It provides the basis for the cosmic distance ladder and helps calibrate other distance measurement techniques.
Tips: Enter the distance to the star in parsecs. The calculator will compute the corresponding parallax angle in arcseconds.
Q1: What is the practical limit of parallax measurements?
A: Current space telescopes like Gaia can measure parallax angles as small as 0.01 milliarcseconds, allowing distance measurements up to about 10,000 parsecs.
Q2: Why is parallax measured in arcseconds?
A: Arcseconds (1/3600 of a degree) are used because stellar parallax angles are extremely small due to the vast distances involved.
Q3: What is the relationship between parsecs and light-years?
A: 1 parsec ≈ 3.26 light-years. The parsec is defined directly in terms of parallax, making it more convenient for astronomical distance calculations.
Q4: How accurate are parallax measurements?
A: Modern space-based measurements can achieve accuracies of about 10 microarcseconds for bright stars, with errors increasing for fainter stars.
Q5: What is the difference between annual and secular parallax?
A: Annual parallax uses the Earth's orbit around the Sun as a baseline, while secular parallax uses the Sun's motion through the galaxy over longer periods.