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Anything that is not the measure of intrinsic brightness of a celestial object.
Cepheids have a certain relationship between their period, and their absolute luminosity. Thus, their absolute luminosity can be determined. Comparing this with their apparent luminosity allows us to calculate their distance.Cepheids have a certain relationship between their period, and their absolute luminosity. Thus, their absolute luminosity can be determined. Comparing this with their apparent luminosity allows us to calculate their distance.Cepheids have a certain relationship between their period, and their absolute luminosity. Thus, their absolute luminosity can be determined. Comparing this with their apparent luminosity allows us to calculate their distance.Cepheids have a certain relationship between their period, and their absolute luminosity. Thus, their absolute luminosity can be determined. Comparing this with their apparent luminosity allows us to calculate their distance.
How do they measure what?
It's distance
The apparent magnitude of a star is a measure of its brightness.
Anything that is not the measure of intrinsic brightness of a celestial object.
I assume you mean the absolute magnitude (brightness) of stars. The problem with this is that it can't be directly measured. What astronomers can measure is the apparent magnitude. To make conclusions about the absolute magnitude, they would also have to know the distance to the star, as well as data about extinction, i.e., how much dust and gas there is between us and the start which may make the light look fainter. Note that the absolute magnitude is very important to characterize a star - but it may be difficult to calculate it with much precision.
Cepheids have a certain relationship between their period, and their absolute luminosity. Thus, their absolute luminosity can be determined. Comparing this with their apparent luminosity allows us to calculate their distance.Cepheids have a certain relationship between their period, and their absolute luminosity. Thus, their absolute luminosity can be determined. Comparing this with their apparent luminosity allows us to calculate their distance.Cepheids have a certain relationship between their period, and their absolute luminosity. Thus, their absolute luminosity can be determined. Comparing this with their apparent luminosity allows us to calculate their distance.Cepheids have a certain relationship between their period, and their absolute luminosity. Thus, their absolute luminosity can be determined. Comparing this with their apparent luminosity allows us to calculate their distance.
Absolute magnitude and apparent magnitude are the same because they are both ways on how to measure the brightness of a star. Absolute magnitude is how bright is the star if we will see it in a 32.616 light-years distance while apparent magnitude is the brightness of it that we see on Earth.
there are two separate ways that astronomers measure the brightness of a start, there is actuall and aparent brightness. In apparent brightness, the measure how bright it looks to all the humans on Earth. However, the actual brightness of a star is different. Say a star is really, really bright, but really far away. That star would look preety dim. Or if a star is not so bright, but really close, like the Sun. The actuall brightness of a star is harder to measure, but is possible by use of waves and stuff like that, I don't know too much about actuall brightness
How do they measure what?
Astronomers use the unit of measure "Light Years" to calculate the distance between pretty much anything in the Universe.
The reference that astronomers use to compare the luminosity of other stars is the sun's luminosity. The luminosity is denoted in multiples of the sun's luminosity. For example, the luminosity of the star Sirius is 25 times the luminosity of the sun.
Astronomers define star brightness in terms of apparent magnitude (how bright the star appears from Earth) and absolute magnitude (how bright the star appears at a standard distance of 32.6 light years, or 10 parsecs).
The measure of a star's brightness is its magnitude. A star's brightness as it appears from Earth is called its Apparent Magnitude.Star's brightness is measured by there magnitude.
The measure of a star's brightness is its magnitude. A star's brightness as it appears from Earth is called its Apparent Magnitude.Star's brightness is measured by there magnitude.
The basic idea is to measure the apparent brightness, and combine that with information about the star's distance, to calculate the real brightness. For example, you may have two stars that look equally bright, but one is known to be 100 times farther. This means the farther of the two stars is also ten thousand (hundred squared) times brighter. Note that the situation may be complicated by interstellar dust and gas, which may absorb part of the light.