I'd forgotten this until I read Lumpbucket's project below (above?)
When I was about 14, I was into astronomy and computers (well, I had a 48k Spectrum anyway). In an astronomy magazine, there was an article about a virtual star atlas running on some awesome "proper" computer, and it even had the core of the code printed for all to learn.
I was so impressed with the idea that I decided to port the program to the spectrum. Adapting the code was the easy bit, as all of the difficult mathematical translations were in the example. It was a bit trickier with the graphics as the existing code was for a completely different renderer, but I managed.
What I hadn't thought through was the time it took to enter all of the data required for the stellar database (available from all good libraries). No scanners, OCR, or online (online? wtf was that in 1982?) facilities existed for me, so I had to enter the lot manually on the Speccy's rubber keyboard: Right ascension, declination, magnitude and colour for each of about 5000 stars. It took me about 4 weeks solid indoors, in the middle of my summer holidays, backing up to a tape every couple of hours or so. What a waste of sunshine!
It worked though, and I was immensely proud of my efforts - I could select any part of the sky and zoom in and out to my hearts content. It was no use to anyone, but I didn't care :)
I have no idea what happened to my tape, so it's all just a hazy memory now.
I also built a telescope at about the same time, which I still get out every now and a again, but I can't be arsed to write about it at the moment.
( P-MONKE We're all fucked, Wed 23 Nov 2011, 19:01, 2 replies)

hmm that only gives you about 9 bytes per star...
not including the memory used to store the program...
( Moon Girl Technologies horrendous beanbag, Wed 23 Nov 2011, 19:46, closed)

It felt like 5000
and I never actually counted - the 5000 figure comes from my hazy memory. In actual fact, I may have referenced Flamsteed's star catalogue which (after a quick Google) "only" lists about the 3000 or so visible from Britain.
The program was probably only 3-4kB max.
9 bytes per star could probably get 5000 into the remaining 44kB with some trick data encoding and judicious rounding, but I wasn't into that kind of thing.
Good sanity check there though :)
( P-MONKE We're all fucked, Wed 23 Nov 2011, 20:27, closed)