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I did a blog post of something related with Minkowski geometry: https://nickp.svbtle.com/asteroid-intersections


I did a toy implementation of a star camera: https://nickp.svbtle.com/star-cameras


The article seems to skip the matching part. I see it in the source code though. But it looks like it's just using two stars, how does that work? I know ASTAP and Astromentry.Net use three or four stars and compute the angles and distances between them.


Each star will give a circle on which you could be located. 2 will be the intersection of 2 circles, which is 2 points. If you have some additional assumptions (e.g. Northern hemisphere), it is possible to eliminate one of the points. Otherwise you need a 3rd point to get a full triangulation.


What you're describing is a lat/lon position fix, but the link nickponline gave is for a plate solver (finding the RA/Dec of stars in an image, and determining the camera orientation). All other plate solvers I've looked at use three or four stars and measure the angles and distances relative to each other. Since nickponline's code appears to only use two, I'm intrigued as to what the angle is being measured relative to. It kinda looks like it requires the image to be oriented with North as up, which seems like an interesting twist. It seems a little like cheating, but honestly most people will know the orientation of their camera, and it probably speeds up the search considerably, and would reduce/eliminate the need for building index files.


https://nickp.svbtle.com/

I try to deconstruct and solve interesting coding problems usually from programming competitions.


I wrote a blog about the general case https://nickp.svbtle.com/general-collectors-problem


Shameless plug on my blog on solving and visualizing problems: https://nickp.svbtle.com/


My first inclination was to write a solver :)

https://gist.github.com/nickponline/9a3fb1ee5333c52ed195625e...


Nice solver! I did optimize the sieve a little...

N = 100000 primes = [False, True] * N // 2 for i in range(3, N, 2):

    if primes[i]:
        k = i ** 2
        while k < N:
            primes[k] = False
            k += i * 2


N = 100000 prime = [False, True] * (N // 2) primes = [] for i in range(3, N, 2):

    if prime[i]:
        primes.append(i)
        k = i ** 2
        while k < N:
            prime[k] = False
            k += i * 2
useful = [ str(i) for i in primes ]

# Enter your clues

for i in useful: if i[0] == '6' and ('3' in i) and len(str(i)) == 5: print(i)


https://gist.github.com/nickponline/9a3fb1ee5333c52ed195625e...


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Maybe you'll like these: https://nickp.svbtle.com/ (shameless plug)


Thanks for this


I would also recommend Concrete Mathematics by Donald Knuth, Oren Patashnik, and Ronald Graham as another refreshing approach.


I really like Concrete Mathematics, but I fear it's a bit too heavy as an intro for most programmers.

(Whoever can stomach it, should give the book a try. It's awesome and fun!)


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