The science dealing with objects and phenomena located beyond Earth. In particular, this applies to observations and data. At its core, astronomy is the physically informed cataloging and classifying of the contents of the universe in order to better understand what is out there.
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Magnitude of New Comet C/2012 S1 (ISON)
A new comet (magnitude 18.8) has been discovered beyond the orbit of Jupiter.
Comet ISON will get within 0.012 AU of the Sun by the end of November 2013 and ~0.4 AU from of Earth early in January ...
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108 views
The validity of the Longitude of Perihelion
As I understand it from Astronomical Algorithms, by Jean Meeus, the Longitude of Perihelion is a very common numeric value associated with planets, even used as one of the planetary orbital elements. ...
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145 views
Angular Diameter, Parallax - Perceived size of Objects
I'm currently in the process of writing a 2.5D Application that should display the perceived size of an Object. For example, When I have a ball that has a diameter of 1meter, how big would it appear ...
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38 views
A few questions related to frame dragging
I am trying to get my head around a few concepts related to frame dragging and related physics. In regards to black holes that have no charge and all thier mass is tied up in rotational kinetic ...
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145 views
Optimal telescope size?
Consider a diffraction-limited telescope with unobstructed aperture $D$. Such a scope is capable of yielding an angular resolution $\alpha$ that scales as $\lambda/D$, with $\lambda$ denoting the ...
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How accurate are Mayan astronomical “ephemerides”?
Because of the hype surrounding the "end" of the Mayan calendar (along with the usual cultural relativism and Western guilt) it is nearly impossible to find an objective quantitative assessment of the ...
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Why is my approach to the equation of time off by a constant?
I'm trying to better understand the causes for the equation of time by deriving an approximation from first principles.
My naive approach, $EOT_{NAIVE}$, is to take the difference between the right ...
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154 views
Mirrors and light beam divergence technology limits
There are many applications for orbital space mirrors in astronomy (better telescopes) and space propulsion (solar power for deep space probes), but this is limited by the minimum beam divergence ...
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How to predict Iridium Flare?
I want to find out how to predict Iridium flares, but I don't know where to start. If I know Solar position, Iridium satelites' TLE and it's shape, I need a magnitude(time) function for some place on ...
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136 views
Determine date of birth from “astrological” signs?
Suppose someone tells me what constellation the Sun, Moon, Mercury,
Venus, Mars, Jupiter, and Saturn were in when they were born, and the
information is astronomically accurate (ie, not astrological ...
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79 views
Parallax Cloud Displacement - Angular Distance from Geostationary Satellite
When observing clouds from a geostationary satellite, they appear displaced because of the parallax effect. The satellite looks at the clouds "at an angle" and it projects them on a point of the earth ...
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63 views
Elimination of the node
Recently I have been reading a lot of astronomy papers on reductions in models of the solar system. A reoccurring concept is the elimination of the node. However, they never explain what the node is ...
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Future space-based telescope array
Radio-telescopes (e.g. the Very Large Array (VLA)) can simulate one gigantic dish by using separate smaller dishes.
Q: Could such an array of optical telescopes potentially see an exoplanet at say 20 ...
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54 views
Could a Class A Stellar Engine Use A Brown Dwarf
Could a class A stellar engine (or maybe a class C one) be built using a brown dwarf (for argument's sake, a T-dwarf like Gliese 229B)? Would it be capable of enough thrust to move itself any ...
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69 views
Calculating distance to an asteroid on a given day
I'd like to calculate the distance between the Earth and an asteroid at a given date. Is this possible using the data from JPL's small-body database? Is there a better way?
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How do I obtain the Point Spread Function (PSF) of a ground telescope?
I have some galaxy kinematic maps (velocity maps) extracted from Integral Field Spectroscopy (IFS) datacubes. Like any observation data coming from a ground telescope, these velocity maps include (ie: ...
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Information-theoretic limits in observational astronomy
It seems to me that with ever larger and better telescopes and powerful statistical methods, humans are gleaning surprising amounts of information from observations of distant stars. I am especially ...
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119 views
What is the angular distance between Ptolemaic perigees of Mercury?
In his excellent treatment of the history of the science of astronomical distances and sizes, Albert van Helden says (p.29) that
The complicated [Ptolemaic] model of Mercury has the curious ...
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Is the conclusion that the cosmic burst observed in the Draco constellation from gamma rays that are streaming towards a massive black hole correct?
Referencing this news article:
http://www.smh.com.au/technology/sci-tech/cosmic-burst-in-far-away-galaxy-puzzles-nasa-20110408-1d6kz.html
It also references an event id:
(GRB) 110328A
The article ...
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26 views
Saturn's angular position with respect to major axis?
Would someone please help me by giving me Saturn's angular position with respect to its orbit's major axis when the Earth is at Vernal Equinox Or at Perihelion?
If not possible please mention some ...
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84 views
Mass loss rate of planetary nebulae
The “interacting wind” model of planetary nebulae is based on the idea that the white dwarf phase of stellar evolution is preceded by a red giant phase. A fast wind from the hot white dwarf overtakes ...
