raxacoricofallapatorius
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 Dec 23 awarded Nice Question Oct 29 awarded Popular Question Sep 30 revised What is the angular distance between Ptolemaic perigees of Mercury? Restore omitted words. Sep 30 comment What is the angular distance between Ptolemaic perigees of Mercury? @Cicero: I doubt it. It's really about the details of the calculation. HSM hasn't proven to be very quantitative. Sep 23 comment How did Kepler arrive at his laws? Also see this. Sep 23 awarded Popular Question Sep 21 awarded Popular Question May 7 revised Should it be obvious that independent quantum states are composed by taking the tensor product? Fix sizing of bras. Apr 22 asked How do I calculate the right ascension of the ecliptic at the points where it intersects the horizon? Mar 31 comment Have CMB photons “cooled” or been “stretched”? @DanSheppard: I think the accepted answer explains exactly that. Mar 14 awarded Yearling Feb 3 awarded Popular Question Dec 21 comment How do I calculate the right ascension of the points along the ecliptic at given elevations? Where do those lines meet? At the sphere's center or at the horizon? In any case I don't have $A$ (at least not readily). But the diagram is helpful: given $a$ relative to the horizon (celestial elevation) and a time (which ultimately gives $A$, but I'm not sure of the calculation — that's a part of the solution I'm looking for, perhaps), I'm looking for $b$ (or better, $b$ measured from a fixed reverence, such as 0 RA). Dec 20 comment How do I calculate the right ascension of the points along the ecliptic at given elevations? @CarlWitthoft: Not sure. But what I've got is $t$ and $X$. In fact lots of $t$s; hundreds or even thousands. So I'm looking for an *algorithm*. I also have most other basic ephemerides (rise, set, transit, etc.; and can do coordinate transforms relatively easily); but what I need is to know what the formula is; or how to extract $RA(X, t)$ ultimately from the ephemerides I have, even if indirectly as $RA(f(X), g(t))$ where $g$ and $f$ are some ephemerides. Dec 20 comment How do I calculate the right ascension of the points along the ecliptic at given elevations? @CarlWitthoft: I've got solar position. What I have is time and a desired elevation; what I'm looking for is is the function used to calculate the point along the ecliptic at that elevation at that time. Dec 20 comment How do I calculate the right ascension of the points along the ecliptic at given elevations? I'll try. But if I could draw it I think I could solve it. In the meantime: At the time the sun sets, t, working eastwards along the ecliptic, how far do you have to go (i.e., what is the RA) of the point that is X degrees above the horizon? Ho do you calculate RA given X and t? Dec 20 accepted Does the length of the sidereal day vary systematically? Dec 20 accepted When is the right ascension of the mean sun 0? Dec 20 asked How do I calculate the right ascension of the points along the ecliptic at given elevations? Dec 16 comment Probability and the many-worlds interpretation Could you have a look at this question. I think your added comments are relevant there and might produce an answer.