Note to self: Always, always, ALWAYS strip exif data.
I would like to know what else is embedded in digital pictures, similar to the printer yellow dots, except it will be undetectable.
Finding the B-21's hangar location from the stars in its press image
51–60 of 228 posts
Re: Finding the B-21's hangar location from the stars in its press image
#52With the casual change from "34-35 degrees" to "lets draw a line at 34 degrees" followed by the "and this is where the press release was" I got the vibe that this was parallel construction. Still some good sleuthing, don't get me wrong, but still.
I don't know if I entirely buy the line on "34-35 degrees off the horizon." Unless we knew the focal length of the lens it was taken with, and which camera it was taken from, you don't actually know that. A wide-angle lens is going to have a much larger field of view than, say, a 100mm macro. And different camera systems have different angle of view for the same focal length.
both the focal length and the field of view are irrelevant, you know the angles between the stars so you can infer everything.
Re: Finding the B-21's hangar location from the stars in its press image
#53[deleted]
Re: Finding the B-21's hangar location from the stars in its press image
#54I feel like the entire thread should have led off with "This is in fact a publicly known hangar in Palmdale and this was known as public information as soon as the unveiling event occurred, and thus this is just an exercise to show how locating the spot could have been possible from just this photo as a technical demonstration." Because I guarantee there are going to be a hundred clickbait articles by various 'news'…
I did mention this later in the thread - was just a fun experiment to see if locating it was possible if we didn't know
Sure, but the reason you didn't lead with that, and also the reason you did this for a secretive aircraft and not a new campervan is clicks, no?
Re: Finding the B-21's hangar location from the stars in its press image
#55Re: Finding the B-21's hangar location from the stars in its press image
#56It's worth noting that stars can be seen even in daylight with the right software. That's because, while no individual star is visible, the exact angles between all stars is fixed, so you can do a brute force search of all possible orientations of the sky to find a matching one. In a 6 megapixel image of half blue sky, you effectively get an oversampling ratio of 3 million:1, so even with very bright sunlight obscuri…
Very interesting! Any links for further reading?
Re: Finding the B-21's hangar location from the stars in its press image
#57With the casual change from "34-35 degrees" to "lets draw a line at 34 degrees" followed by the "and this is where the press release was" I got the vibe that this was parallel construction. Still some good sleuthing, don't get me wrong, but still.
I don't know if I entirely buy the line on "34-35 degrees off the horizon." Unless we knew the focal length of the lens it was taken with, and which camera it was taken from, you don't actually know that. A wide-angle lens is going to have a much larger field of view than, say, a 100mm macro. And different camera systems have different angle of view for the same focal length.
You know what the angle between the stars in the constellation are, you don't need to know the field of view of the camera.
Re: Finding the B-21's hangar location from the stars in its press image
#58Omg I opened a Twitter thread and when that dreaded moment came where that black takes over the screen and I can’t even scroll back anymore… now I was able to just tap an X and keep reading! Hooray for Elon?
Re: Finding the B-21's hangar location from the stars in its press image
#59It's worth noting that stars can be seen even in daylight with the right software. That's because, while no individual star is visible, the exact angles between all stars is fixed, so you can do a brute force search of all possible orientations of the sky to find a matching one. In a 6 megapixel image of half blue sky, you effectively get an oversampling ratio of 3 million:1, so even with very bright sunlight obscuri…
Very interesting! Any links for further reading?
Nope - years ago I accidentally discovered this while trying to align star images for stacking. Some of my images were taken in daylight, and I was surprised to find my rudimentary image aligner still worked just fine. Never wrote it up into a blog post.
Re: Finding the B-21's hangar location from the stars in its press image
#60Note to self: Always, always, ALWAYS strip exif data.
Couldn't the same conclusion be reached, without? That plane flying overhead, center, would probably make things much easier.