Talk:Parallax
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This is a good description of parallax. But it's a difficult thing to explain and I think a picture would help.
The article should be expanded in relatioship with cameras.
- I have a question at talk:Single lens reflex camera. --KQ
Mention added! - MV
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[edit] parallax
you described it rather akwardly I think. The simple definition I have learned describes it I feel more simply. Parallax is the apparent movement of one object relative to another due to the movement of the observer.(o.k don't have permisson to copywrite this but hey its a leaving cert definition and is used by thousands of students every year) Show diagrams of the simple pen experiment where you hold two pens out in front of you, one above the other. The bottom one slightly further away from your face than the top. move your head and you will see parallax. But you know this already right?
OK, I added your simple definition (reworded). A drawing would be good, but I am no good at drawing - MV
What about diurnal parallax of solar system bodies?
[edit] Example Diagram
I agree that the page needed a clear, concise diagram with similar explaination - I threw something together in (don't laugh) Microsoft Word... Should be good enough until a real artist decides to make something reasonable.
The previous "informal introduction" was far too wordy and very unclear, even to someone who knows precisely what parallax is. Hopefully this should rectify the situation.
Someone improve my formatting (and image) if you like :)
[edit] References?
I really think this is an excellent article, to the point where I believe it would make a great featured article, but unfortunate it lacks the key requirement of good references which allow people to verify our information. Could the authors of this article add some references describing where they picked up this information? Whether it's online or not it'll still be helpful. Thanks. Deco 21:02, 7 May 2005 (UTC)
- I second this motion. I will try and find a few myself, but there's so much here... If this ever gets nominated for possible featured article status, I think I'll clean up the parallax image I made into something a bit nicer. - JustinWick 23:10, 7 December 2005 (UTC)
[edit] Stellar parallax
The problem with the argument against heliocentrism was not that a huge size of the universe didn't occur to anyone; it's that the size was incredible. Aristarchus himself explained that the size of the sphere of fixed stars was effectively infinite compared even to the Earth's orbit. Archimedes rejected that, mainly on a quibble with the language Aristarchus used. Tycho understood the argument but thought he had good reasons to believe that the universe couldn't be as big as the lack of parallax implied. --Dandrake 00:25, Jun 11, 2005 (UTC)
[edit] I'm old!
1 quibble: recent research puts age of the universe @13.8GY, doesn't it? Trekphiler 07:23, 29 December 2005 (UTC)
[edit] Confusing wording
What does "The parallax 
in arc seconds" mean? I think the equals sign is substituting for the word "equals"? This wording needs to be clarified. --AySz88^-^ 21:55, 9 February 2006 (UTC)
[edit] confusing symbol choice
In an article so heavily dependent on trig and geometery, is it really very clever to denote the parallax angle by π (as opposed to its more usual use as the ratio of circumference to diameter)? This forces the reader to decide whether the error in distance is proportional to the error in angle divided by the angle squared, or by a constant approximately equal to 9. And yes, of course one can see the derivation quickly... but nothing is gained by this momentary confusion, and someone not clear on the concept (i.e., the sort of person likely to be looking it up) is less likely to be confident in the derivation.
- Unfortunately astronomers have been using π to denote parallax for well over a century. While it would possibly reduce some amount of momentary confusion, I think consistancy with other sources trumps in this case. --anon 7sept2006
[edit] Stellar parallax
To what range can parallax methods reliably determine the distance to a star? Is it any more than 6000 light years? If it is, than this is an excellent method for proving the universe is older than what biblethumpers declare. Wouter Lievens 12:09, 14 June 2006 (UTC)
- It's about 1000 parsecs, and that comes to 3300 light years.Magmir 02:40, 23 February 2007 (UTC)
[edit] Linking
Science Buddies at www.sciencebuddies.org has many resources and ideas for science fair projects that involves ideas on this website including parallax.
[edit] Oscilloscopes
This is where I first met the word parallax: In an old CRT oscilloscop, the electron beam (cathode ray) draws a pattern on the phosphor inside the glass, which the operator reads along a grid pattern drawn on the outside of the glass. If the operator moves his head, a parallax reading error might occur. The same kind of reading error can occur in moving needle instruments (analog voltmeters, ampèremeters), which is why precision instruments had a mirror in the scale. When the needle covers its own mirror image, the operator's head is straight above the scale, without any parallax. --LA2 23:33, 26 January 2007 (UTC)
