Posts by BenWilson
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Capture: Got the blues, in reply to Nora Leggs,
Kitten Kong!
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One especially easy way of easing the power load into Auckland would be legislative, insisting all carriers must support reversible metering, and must pay the same price they charge for the power. Then putting solar on the roof would be an extremely easy decision, a small investment with reasonably rapid pay-off time. No need for government investment. But this might hurt the bottom line profits of power companies. It should not be as hard as it has been for the small number of people who have done it.
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I'm sure this is an optical illusion: Rangitoto seems to be the source of the clouds. Presumably it's because it's the vanishing point for clouds that are strangely lined up.
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Capture: Got the blues, in reply to ChrisW,
Copper chopper circling Herne Bay at an annoyingly low height for half an hour. I'm surprised by how slow the props actually turn.
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Capture: Got the blues, in reply to BenWilson,
I wasn't keen to model the maths. I've only got so much of that in me per day, and today's is all gone on a physics assignment.
OK, that's not true. To help me sleep, I worked this one out to follow the other two derivations here. If you imagine 3 points, your eyes, the center of the earth, and the horizon, then they form a right angled triangle with the right angle on the horizon. The long side is the one from your eyes to the center of the earth, length r + h, where r is the radius of the earth and h is the height of your eyes. One other short side is length r (to the horizon from the center). We want to find the other side, call it c, from your eyes to the horizon. After Pythagoras and some algebra, we get c = sqrt(h^2 + 2rh). r is approximately 40000/(pi*2), just from the original definition of a meter as one ten thousandth of the distance from the North Pole to the Equator (through Paris, I think). I get 6366km. So if h = 0.0018km, then c = 4.78km. This derivation has the advantage of not requiring terrestrial heights. At 100,000km from the Earth, the horizons are 106,175km away. Now I can sleep.
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Capture: Got the blues, in reply to ChrisW,
And what planet are you on? Apparently planet Kulthea! Strange to say - you looked up fiction in the quest for truth! ;-)
Classic! Actually I looked up Yahoo answers first, and only gave that link because of a convenient tabular form, which happened to agree with other answers that I'd checked to within the very loose distances I was using.
accurate for practical purposes for all human to mountain-scale heights.
I wasn't keen to model the maths. I've only got so much of that in me per day, and today's is all gone on a physics assignment.
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Capture: Got the blues, in reply to Lilith __,
Sorry Ben, I don't mean to be a pain about this, but I'm really fascinated.
Not at all, I'm interested too. Feel free to take this off-line (we've got each other's emails), unless anyone else is interested to hear about this.
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5km seems a pretty sort distance for you to be seeing the earth curve.
Truth is stranger than fiction. I looked this one up before I wrote it, but I did also remember that it's a lot closer than one might think, when one is down low - for instance sitting in a lifeboat. My estimation of the height of the camera, which was pressed to my eye, is that it was about 1.8m above sea level (I'm around 1.95m tall). So the horizon is about 5km away. I would be completely unable to see the bottom 1.8m of any object 10km away.
It is very hard to be sure of how far away the boats were, as the height of their masts is unknown. But at full zoom, a similar appearing vessel fills the entire shot at a distance of around 500m. The closest vessel is 422 pixels high in the shot above, out of 3216 pix. So that makes it around 3.7km away. The one beside it comes up only 200 pixels, so it's over twice as far away, if it's mast is roughly the same height. That puts it around 8ish km away, beyond the horizon. This is sort of confirmed by the other shot which is from somewhere between 4 and 5m above sea level, in which the furthest boat seems to be on the horizon. This suggests it's about 7-8km away at the time of that shot, which is 45mins before the sea level shot. The ship was making good headway out to sea the whole time, so could easily be a further 3-4 km out by then.
ETA: Which is not to say there isn't mirage effect there. I'm sure there is, because it can be seen in this shot, containing Little Barrier Island, which is something like 50-80km beyond. You can see the corner is floating. But notice that this floating is also above the height of the decks of the boat on the horizon, but that is reasonably clear and undistorted. This suggests the mirage effect is happening mostly beyond that point.
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A couple of years ago, I really though asset sales were going to hurt the National government. But somehow we've entered a time where discourse that involves hurt and pain only makes them more popular. So long as someone somewhere is getting screwed by National, then they must be doing a good job. It's what strong leaders do in tough times, they screw people to make the hard calls. Lost in that discourse is that weak ineffective leaders can also do that, that you can screw people over to no good effect for the public weal at all.
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Extremely high flying kite over Richmond Park (in January I think). Full zoom (24x). Very hard to know how high it was, but my guess is that it was several hundred meters up. The strings were completely invisible, and other people, when I told them where it was, took quite some time picking it out against the sky. It was straight above me, and I only saw it because I was lying on my back on the grass under a tree. Could not ascertain where the pilot was. I think it's one of those really big ones, a couple of meters across. A bit cheeky to fly it over a suburban area, but hey, I expect most people never saw it.
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