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Re: Optics B/C
Posted: October 10th, 2011, 5:13 am
by cngu23
Infinity Flat wrote:cngu23 wrote:chalker wrote:
Does anyone who has competed in the event before know exactly which parts of the eye we should cover? Or do we need to know all of them?
The set-up time includes the calculations.
Last year, you were given points for doing the laser shoot in as little time as possible, as well as for accuracy. So, most people who scored well probably did it in under 10 seconds
This year, the time component is replaced with the number of mirrors used, so I'd imagine that more people will use the full 4 minutes.
Thanks.
![Smile :)](./images/smilies/icon_e_smile.gif)
My partner and I mostly took notes from the section on eyes in a few Biology textbooks. (this is usually under the anatomy section.)
You're allowed a binder for this event, so as long as you keep everything organized, there's no such thing as to many notes!
[/quote]
I expect that most of my notes will also be on the anatomy of the eye. So do you know exactly how the points are calculated?
Like, which of these gives more points?
- using 1-2 mirrors but 100% accuracy?
- or 5 mirrors but slightly less accurate?
Does accuracy or the number of mirrors play a greater role in point calculation?
I'm expecting the answer to the the accuracy of the beam.
Re: Optics B/C
Posted: October 10th, 2011, 9:58 am
by chalker
cngu23 wrote:
I expect that most of my notes will also be on the anatomy of the eye. So do you know exactly how the points are calculated?
Like, which of these gives more points?
- using 1-2 mirrors but 100% accuracy?
- or 5 mirrors but slightly less accurate?
Does accuracy or the number of mirrors play a greater role in point calculation?
I'm expecting the answer to the the accuracy of the beam.
You should really get a copy of the rules so you can look at the scoring formula. Each mirror is 4 more points and each cm you are off is 1 point.
Re: Optics B/C
Posted: October 12th, 2011, 5:39 pm
by geekychic13
so, stupid question. if you have bad eyesight, do you have spherical aberration? and if so, do contact lenses/glasses fix that?
Schrodingerscat wrote:JSGandora wrote:
So, why is spherical aberration reduced if many lenses are used? It seems unintuitive to me because each lens has some spherical aberration and it piles up (intuitively, although I may be wrong).
http://en.wikipedia.org/wiki/Schmidt_corrector_plate
Non-spherical shaped lens, such as the Schmidt corrector plate, can correct by correcting light more or less at different radii. However, I am not aware of spherical lens being able to correct spherical aberrations.
Re: Optics B/C
Posted: October 12th, 2011, 5:40 pm
by tuftedtitmouse12
contact lenses do fix it but depending on whether you are near or far sighted, changes the type of lense
EDIT: i believe convex would be for near sighted while concave is for far sighted...correct me if i am wrong, since i haven't been so studious with optics this summer...my knowledge is what is left over from last year that has rotted over the summer >.<
Re: Optics B/C
Posted: October 12th, 2011, 5:46 pm
by JSGandora
Near-sided - diverging lens
Far-sided - converging lens
Re: Optics B/C
Posted: October 12th, 2011, 6:15 pm
by Schrodingerscat
geekychic13 wrote:so, stupid question. if you have bad eyesight, do you have spherical aberration? and if so, do contact lenses/glasses fix that?
It depends upon why one have bad eyesight. If one is simply shortsighted, the lens cannot reduce its power enough to focus on a distant object. Farsightedness, however, results when the lens is unable to increase its power enough to focus a nearby object. These can be corrected by adding an additional lens with either negative or positive power to allow a normal range of focus. Some other eye conditions such as Astigmatism do result from aberrations of the lens. (Astigmatic aberrations.)
Re: Optics B/C
Posted: October 13th, 2011, 3:01 pm
by geekychic13
Schrodingerscat wrote:geekychic13 wrote:so, stupid question. if you have bad eyesight, do you have spherical aberration? and if so, do contact lenses/glasses fix that?
It depends upon why one have bad eyesight. If one is simply shortsighted, the lens cannot reduce its power enough to focus on a distant object. Farsightedness, however, results when the lens is unable to increase its power enough to focus a nearby object. These can be corrected by adding an additional lens with either negative or positive power to allow a normal range of focus. Some other eye conditions such as Astigmatism do result from aberrations of the lens. (Astigmatic aberrations.)
thnx. so it is possible that you have spherical aberration, right??? sry, my brains not on. im still kinda confused
![Smile :)](./images/smilies/icon_e_smile.gif)
Re: Optics B/C
Posted: October 13th, 2011, 3:17 pm
by JSGandora
Spherical aberration is already corrected by the curvature of the retina.
Re: Optics B/C
Posted: October 13th, 2011, 6:37 pm
by cngu23
JSGandora wrote:Spherical aberration is already corrected by the curvature of the retina.
But astigmatism changes the shape of the eye, so the image does not focus on the retina.
Re: Optics B/C
Posted: October 13th, 2011, 6:46 pm
by JSGandora
Oh, I didn't think he was still referring to astigmatism. Then yes, there would be spherical aberration in that case.