Talk:Beta angle
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Question: Mathmatical/Factual Error ?
[edit]This line appears in the article:
- The extreme values of beta angle over a years time for a mission launched at a given orbit inclination, , varies ± 23.45 degrees. In other words, for a due east launch from the Kennedy Space Center, =28.5o, and the beta angle will vary from about = +52o to = -52oover the course of a year
Am I half asleep, or does this math seem to be incorrect? If the beta angle varies ± 23.45o/year , assuming a starting beta angle (to keep the math simple) of 23.45o, then wouldn't max = 46.9o and min = 0o? I'm no astrophysicist, and this line is cited, so can anyone clear up my confusion - or am I right? Thanks! Spiral5800 (talk) 18:15, 18 June 2009 (UTC)
- After re-reading and reconsidering, I realized that the section in question is talking about inclination, and currently the article does not have an equation that directly relates and . I will see if I can find such an equation. Spiral5800 (talk) 12:10, 26 August 2009 (UTC)
- I've come to think that due to orbital precession effects, any equation describing the relationship between and would be a very complex differential. I doubt digging one up (or figuring one out) would really contribute to the article anyway. Spiral5800 (talk) 14:09, 2 December 2009 (UTC)
GA Review
[edit]- This review is transcluded from Talk:Beta angle/GA1. The edit link for this section can be used to add comments to the review.
Reviewer: Spiral5800 (talk) 11:13, 15 June 2010 (UTC)
I am the wikipedian who originally created this article, after watching a shuttle launch one day and hearing the announcers talk about the 'beta angle'. To my astonishment, "beta angle" wasn't listed on wikipedia! Since I started the article, a number of very intelligent and thoughtful people have visited and added to it, and the article has changed profoundly since I made the initial posting. For a topic as relatively narrow as this one, its hard to imagine expanding it [too] much more from the point it has reached at this point. That said, we haven't reached the featured article status yet by a long shot - though I believe that we certainly have reached the good article criteria. I know my vote doesn't count, so I vote for world peace ;) Spiral5800 (talk) 11:13, 15 June 2010 (UTC)
Hi there. I see there's a note above that 'an editor' has agreed to review the article, but since there's no sign of any activity on that front in the three weeks or so since that message was left, I'm going to disregard it and carry out a full review. If there's any objection to that approach, just let me know and I'll leave the article alone. Cheers. 4u1e (talk) 13:06, 7 July 2010 (UTC)
- Images: Provisional fail Useful and show the concept. However, while they're tagged as being Spiral5800's own work, they contain an image of the sun, which I'm guessing you didn't take yourself! Whose image is this and do we have the right to modify and re-use it?
- Stability: Pass No edit wars etc.
- Neutral: Pass Seems to be no controversy here.
- Breadth: Pass Seems comprehensive for this use of the term. I recommend that if you want to take the article any further, you find some good quality hardcopy references on astronautics, as there may well be more detail on how it is calculated for example. There are other uses of this term (one in structural mechanics, for example), but as this article is clearly focussed on one meaning, I don't believe this is a problem.
- Accurate and verifiable: Provisional fail Going by the letter of the GA criteria, there are two places in which you need to provide inline citations, by my reckoning. However, although it is not required for a pass, I recommend that you go through and provide inline citations for the whole thing. Looks like you have sufficent sources to fix this. Also the use of ref 1 in the final para is incorrect - the term "beta cutout" does not occur in that reference.
- Well-written: Fail: Not sure this is the right section to put this under, but some of your article repeats your sources word for word. The example that I first noticed was the first para of 'Determining a Beta Angle', which is almost identical to the third para of the 'Beta Angle' section of your second reference. There are other individual sentences copied from this source and from the third reference. This is a copyright violation (one could call it theft). This and any other copied material must be fixed by re-writing the article in your own words.
- Less importantly, but still necessary, the lead gives more detail than the main article. Move the detail into the main article and trim down the lead to be a summary of the whole article.
- Overall: Fail The other things could be fixed fairly quickly, but I can't pass an article with such significant copyright problems (there may be an issue with the pictures as well as the words). Hope you can fix the problems and get through GA next time. Cheers. 4u1e (talk) 20:19, 7 July 2010 (UTC)
Copyright violation
[edit]As regular editors of this page have not acted on the copyright violations identified above, I've removed the following problem items:
- First para of 'Determining a beta angle' was almost word for word identical to the third para of the 'Beta angle' section of this page.
- Both images, although tagged as being released into the public domain by user:Spiral5800, are based on this image, for which the copyright conditions specify educational and non-commercial use (not suitable for Wikipedia) and also request attribution which has not been given. 4u1e (talk) 05:08, 2 August 2010 (UTC)
- Thanks for the attention to detail. I did construct those images myself on "paint", I believe, and although they were based on images I'd seen elsewhere, they were indeed original material. As this is an article concerning orbits, and as orbits (though elliptical) in many cases can be approximated by circles, I fail to see how anyone could have defined a beta angle in a diagram without making your alleged copyright violation; I do agree that the images of the sun that were later added to the illustrations for clarity had an unclear copyright status, though I would argue that the article would have best been served by reverting to the older versions of the illustrations that lacked the sun image rather than entirely removing the illustrations. Besides the sun, which was amended to the illustrations long after their original versions appeared here, the images were composed entirely of the simplest and most common geometric illustrations - specifically a circle and a few line segments - and if circles or circles with line segments intersecting them are somehow copyrighted and off-limits, then wikipedia has far bigger concerns than this article. Thus, after waiting a year, I am going to re-add the illustrations to this article as the illustrations make the article vastly more accessible to the layperson, among other reasons. I intend to re-draw them myself from the definitions already outlined in the article so as to avoid any further allegations of copyright violations, though I feel strongly that the removal of the original illustrations was overly haste and insufficiently justified, especially due to their extreme simplicity. So far as I am aware, one cannot make a copyright claim on a diagram of a circle with one or two lines drawn through it. If one can, then please let the world know that I hereby copyright the platonic solids and any depiction of them must be removed from wikipedia except where my explicit consent has been given. Also, although the first couple sentences of the article originally resembled the source from which the information was taken, all wiki editors should know that one of the most important and upheld policies of wikipedia is the NOR - NO ORIGINAL RESEARCH. I apologize if it was thought that those first sentences were not reworded - thesaurisized - to the extent someone seemed to think appropriate, but the information was clearly cited and there are only so many ways to describe a mathematical concept. If anyone still perceives a problem, then please head on over to the article on pi - but hold your hands to your head tightly to prevent it from exploding. If you survive this experience, your detailed explanation of why it is a copyright violation to define pi by saying "pi is defined as the circumference of a circle divided by the diameter of said circle, which is a constant with the approximate value of 3.141592...". Just because someone else has said something somewhere else on the topic before the article (whether this one or the one about pi) was created does not mean that it's a copyright violation for someone else to say the same thing elsewhere at a later date. Pi will remain 3.141592... (etc) regardless of how many sources discuss it; the idea that posting "pi is approximately 3.141592 ..." is somehow a violation of someone's copyright is just as inane - and insane - as taking issue with the definition of beta angle as described in this article. What about E = MC^2? How would one prefer that to be re-defined or rewritten to conform with such an oddly skewed reading of wikipedia's guidelines? If the same standards that were applied to this article a year ago were applied to the whole of wikipedia, there would be no wikipedia. I hope this is as obvious to others as it appears to me.
- I hope I have properly illustrated how ridiculous this was. I also hope that my waiting a year before returning the diagrams to the article (in the hope that someone besides myself might rectify this issue) is taken as a sign of good faith, patience, and respect for my fellow editors. A year has gone by and nobody else has taken it upon themselves to add illustrations to this article (illustrations that are desperately needed to clarify the material and make it accessible), so I therefore feel that doing it myself - over again - is more than justified. I certainly look forward to reading any (hopefully elaborate) explanation if anyone continues to think that my adding a simple diagram that I drew myself in a few minutes with simple "paint" software - featuring only circles and line segments that have been drawn by mathematicians and engineers alike for literally thousands of years - somehow violates any copyright rules, or any other wikipedia rules for that matter. That said, my sincere respect for editors here leads me to not anticipate any further attempts by editors to tie themselves up in illogical knots of arbitrary "reasoning" in order to decrease the accessibility and value of this article .... at least, not until they first remove all the diagrams from the sphere article, the circle article, the tesseract article, the angle article - and so on. Spiral5800 (talk) 01:30, 16 August 2011 (UTC)
"Importance in Spaceflight" section has inadequate explanation
[edit]This section doesn't deliver what it promises, an explanation of why beta angle is importance in space flight. It expresses some relationships between what beta angle existed on the ISS and what the Space Shuttle was required to do but offers no clue as to why that's the case. Why does the orbiter go into "rotisserie" mode if the beta angle is great than 60 degress? Why can the orbiter only launch to the ISS during a beta cutout? Does flying in high beta angle turn astronauts into zombies? Does it cause moss to grow in the thruster nozzles? After reading I know beta angle is important but have no idea why. I assume it has something to do with temperature or light? 72.64.98.101 Steevithak (talk) 15:51, 21 December 2014 (UTC)
Improve diagram
[edit]![]() | It is requested that an orbital mechanics diagram or diagrams be included in this article to improve its quality. Specific illustrations, plots or diagrams can be requested at the Graphic Lab. For more information, refer to discussion on this page and/or the listing at Wikipedia:Requested images. |
The current diagram is not clear; the sun vector appears to be in the orbital plane. —Swpbtalk 19:36, 13 November 2015 (UTC)
Equation
[edit]There's an alternative formulation , which can be found in the Spacecraft Thermal Control Handbook, Volume 1, page 40;
They're just different. The formula is STCH is in terms of solar RA and DEC (in the equatorial coordinate system) as opposed to the given formula, which is in solar longitude (in the ecliptic.)
β(t) = arcsin ( cos ( δS (t) ) · sin ( i ) · sin ( Ω(t) - ΩS (t) ) + sin ( δ S (t) ) · cos ( i ) )
δS = solar declination ΩS(t) = solar right ascension
This is simpler in some ways, but they are equivalent.