Questions tagged [fundamental-astronomy]
Questions involving reference frames, time scales, and how they are determined. Not for general Astronomy 101 questions.
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How Did Early Astronomers Measure Distances?
Prior to the era of radar and other forms of radio/RF/EM ranging, what approaches, methods, and techniques did early astronomers (e.g., Kepler, Cassini, Copernicus) use to measure the distance(s) from ...
user28134
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Question on dec 2013 answer to"How to measure the altitude and azimuth of a star?"
I am looking at your response to the above question. You stated:
For Northern Hemisphere, a star that is crossing the North local meridian (that is, between the Zenith and the North Horizon) the ...
user28084
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Basis of color index
As an amateur astronomer for 60 years and always as interested in the science as in the observing, I thought I had a pretty good understanding of the fundamentals. But I'm distance-auditing a third-...
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How to determine the eccentricity, knowing the orbital speed and distance
How to determine the orbital eccentricity of a planet, knowing the instantaneous orbital speed of it and the distance from the Sun to the planet at that moment?
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Does any asteroid we have ever seen have a hot core like earth.?
I was wondering if any of the asteroids we have ever seen has a hot core like Earth's.
I'm thinking that Earth has a strong gravitational field and so formation would have involved a lot of ...
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Making sense of the lomb-scargle periodogram
I am trying to use the periodogram to tell when a signal is periodic or not by following the tutorial for the astropy Lomb-scargle periodogram here.
http://docs.astropy.org/en/stable/stats/...
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How to calculate declination of Moon?
Is there any way to calculate declination of Moon for any day?I'll subtract inclination of Earth on the ecliptic from the result. I'll get Moon's the shortest angular distance from Sun.
Thanks for all ...
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Why the more-luminous star has larger surface area when two stars have the same temperature?
If two stars have the same temperature but one is more luminous than
the other, the more-luminous star must have a larger surface area, and
therefore a larger radius than the dimmer star.
The ...
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What do the months and hours mean in Tomas Filsinger's Map of The Universe
I have had one of these in my room for decades:
I don't have the booklet that seems to usually come with it, can someone explain to me what the months (with days below it) and hours mean? I imagine ...
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Do interstellar asteroids decelerate and eventually stop?
I do wonder, do interstellar asteroids eventually stop at one point in space after they gradually decelerate (or) even do they decelerate?
Though there is no air like on earth and thus asteroids ...
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What does half-lit means?
Aristarchus estimated the relative distance of the Sun and Moon by
observing the angle between the Sun and the Moon (α in the diagram)
when the Moon is exactly half lit. Angle β must be 90° for ...
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Necessary steps to calculate photon's path by using null geodesic equation
Can anyone please give me an explanation on how to calculate photon's path by using the null geodesic equation? N.B. I know all of the non-zero values of Christoffel symbols.
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Luminosities and Apparent Brightness of Two Stars of which one is 8 times the distance of the first star [duplicate]
Suppose two stars have the same apparent brightness, but one star is 8 times further away than the other. What is the ratio of their luminosities? Which one is more luminous, the closer or the further ...
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The Luminosity of two stars with same brightness but at different PC away
Stars A and B are both equally bright as seen from Earth, but A is 120 pc away while B is 24 pc away. Which star has the greater luminosity? How many times brighter is it?
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Why do most of the myths behind constellations originate from Greek? [closed]
Why do most of the myths regarding constellations happen to have begun from Greek civilization? Why not other civilizations?
Most people who lived in the past era probably observed star patterns in ...
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