81–90 of 358 posts
You can see one of these up close - both the device, and the airplane! - at the Evergreen Aerospace Museum in McMinnville, OR. They also have on display another Blackbird payload labeled DEF-H. It’s a nondescript white box which you are allowed to look at, but not allowed to know what it does. XD
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OK. Now please do the same with a Z-80 class CPU.
Compared to the rest of the engineering, I don’t think the computation is all that hard. It doesn’t need to be that fast since you only need to do a correction maybe every 10-20 minutes or so. The math was innovative in that they invented the Kalman filter for these types of computations. You pick your star such that it’s by far the brightest one in its neighborhood. So the image processing is just finding the bright…
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I got to see an SR-71 on display in New York several years ago. What really struck me was how BIG it was, seeing pictures of it doesn't really give you sense of scale, it was a massive plane.
You can get close enough to touch (but you mustn’t touch) the SR71 at the Udvar-Hazy center of the Smithsonian!
You can see one of these up close - both the device, and the airplane! - at the Evergreen Aerospace Museum in McMinnville, OR. They also have on display another Blackbird payload labeled DEF-H. It’s a nondescript white box which you are allowed to look at, but not allowed to know what it does. XD
I got to see an SR-71 on display in New York several years ago. What really struck me was how BIG it was, seeing pictures of it doesn't really give you sense of scale, it was a massive plane.
(I was also impressed by how many aircraft could fit on an aircraft carrier. There was also a Concorde!)
When I first heard of astro-nav (for missiles) I thought it was so future sounding, like star trek. But now that I do astrophotography regularly it's just another tool that I use. It's super simple to do, I can take a photo of the night sky, and if I know the focal length and pixel size of my camera I can figure out exactly where my telescope is pointed in seconds, with an accuracy 2.5 arcseconds. You can even do it…
What software do you use to accomplish this?
https://nova.astrometry.net/ will do the blind solve.
If you want to learn more the keyword to google is "plate solving"
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The International Date Line and the 180-degree line of longitude have bitten a _lot_ of folks who don't think to test at the boundaries.
We had a great example of this in a recent Geomob London talk: ask Google Maps to route from Wairiki, Fiji (-16.8048, 179.9893) to Welagi, Fiji (-16.7349, -179.9439), two villages on the coastal road of the same island and about 10km apart, but as you can see from the coordinates on opposite sides of the anti-meridian. You get "Sorry, we could not calculate driving directions from "Wairiki, Fiji" to "Welagi, Fiji" ht…
It's wild that on google maps, even dropping a pin on the Tavuki road and trying to drag it across the line, it just stops, hitting this invisible wall.
Something about this experience makes me want to go there....
When I first heard of astro-nav (for missiles) I thought it was so future sounding, like star trek. But now that I do astrophotography regularly it's just another tool that I use. It's super simple to do, I can take a photo of the night sky, and if I know the focal length and pixel size of my camera I can figure out exactly where my telescope is pointed in seconds, with an accuracy 2.5 arcseconds. You can even do it…
OK. Now please do the same with a Z-80 class CPU.
If you know roughly where you're looking, the lookup is really quite quick.
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I think it is waaaay older. The north star and the southern cross probably guided humans since they had some sort of consciousness. If you see the night sky every night (without distracting screens), the shapes became kind of familiar.
Nitpick: The North Star (Polaris) wasn't used over 4000 years ago: So now you can see why Polaris will not always be aligned with the north spin axis of the Earth - because that axis is slowly changing the direction in which it points (precession)! Right now, the Earth's rotation axis happens to be pointing almost exactly at Polaris. But in the year 3000 B.C., the North Star was a star called Thuban (also known as Al…
You can see one of these up close - both the device, and the airplane! - at the Evergreen Aerospace Museum in McMinnville, OR. They also have on display another Blackbird payload labeled DEF-H. It’s a nondescript white box which you are allowed to look at, but not allowed to know what it does. XD