Difference between revisions of "Absolute Magnitude"
Line 83: | Line 83: | ||
* '''Absolute Magnitude:''' The apparent magnitude, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction | * '''Absolute Magnitude:''' The apparent magnitude, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction | ||
− | == References & Contributors | + | == References & Contributors ([[Sources]]) == |
{{Advanced}} | {{Advanced}} | ||
{{Sources | {{Sources | ||
Line 92: | Line 92: | ||
− | {{MET|Science|}} | + | {{MET|Metric|Science|}} |
Revision as of 04:08, 17 March 2019
Magnitude is a measure of the brightness of a star, planet, or other object in space. The scale is logarithmic and the brighter the object the lower the number.
Magnitude is usually one of two types:
- Apparent Magnitude (m) and...
- Absolute Magnitude (M). Absolute Magnitude is the brightness at 10 parsecs distance.
Description (Specifications)
Given the absolute magnitude and the distance to a star, the apparent magnitude can be calculated by: <math>m = M + 5((\log_{10}D)-1)</math> where D is the distance in Parsecs (must be adjusted for extra galactic objects). Thus Antares at M -5.28 as seen from Capital (distance of ~38 parsecs) would be:
<math>m = -5.28 + 5((\log_{10}38)-1)</math>
<math>m = -5.28 + 5(1.58-1)</math>
<math>m = -5.28 + 5(0.58)</math>
<math>m=-5.28 + 2.9</math>
<math>m=-2.38</math>
Absolute/Apparent Magnitude
Absolute/Apparent Magnitudes for comparison:
Object | Absolute Magnitude | Apparent Magnitude (Terra) | Apparent Magnitude (Capital) |
---|---|---|---|
Sun | 4.83 | −26.73 | 10.38 |
Moon (full) | n/a | −12.6 | n/a |
Visible during Daylight | n/a | −3.9 | -3.9 |
Moon (new) | n/a | –2.5 | n/a |
Sirius Brightest Star | 1.42 | −1.47 | 6.97 |
Canopus 2nd Brightest star | −5.53 | -0.7 (-2.04) | (0.73) |
Vega 5th Brightest star | 0.58 | 0.03 | 5.96 |
Antares 16th Brightest star | −5.28 | 1.09 (0.83) | -1.35 (-2.38) |
Deneb 19th Brightest star | −8.73 | 1.25 (-2.2) | 0.96 (-3.09) |
LBV 1806-20 | −14.2 | 8.4 | 8.4 |
Quasar 3C 273 | −26.7 | 12.8 | 12.8 |
- Note the numbers in () above are for adjusted locations of stars on the maps.
History & Background (Dossier)
On ancient Terra the stars of the sky were divided into 6 magnitudes, with 1 being the brightest and 6 the faintest with each division being approximately 2 times difference, this was later revised so that a 1st magnitude star was 100 times brighter than a 6th magnitude star. First Polaris then Vega were taken to be the 0 point on the scale. So each step is the fifth root of 100 different (2.512).
Magnitude is not limited to the 0-6 scale, most primary stars will be highly negative (Sol from Terra is −26.73). The faintest magnitude visible with a human eye is 6.5. Binoculars give 9.5, and an 8m Ground Telescope can resolve to 27.
- Apparent Magnitude: A measure of its brightness as seen by an observer on the ground, normalized to the value it would have in the absence of the atmosphere
- Absolute Magnitude: The apparent magnitude, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction
References & Contributors (Sources)
- Wikipedia (various)
- Traveller Wiki Editorial Team
- Author & Contributor: Lord (Marquis) and Master of Sophontology Maksim-Smelchak of the Ministry of Science