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Someone should make a game about: The Palomar Observatory Sky Survey

The POSSibilities are endless.

Hello, and welcome to our new series which picks out interesting things that we'd love someone to make a game about.

This isn't a chance for us to pretend we're game designers, more an opportunity to celebrate the range of subjects games can tackle and the sorts of things that seem filled with glorious gamey promise.


Shortly after we published this piece this morning we received this tweet from Jon McKellan, the creator of Observation:

Firstly, this is BRILLIANT. Secondly, Jon was kind enough to tell me a little bit about the use of POSS in Observation: (Be warned, the last paragraph contains a spoiler.)

"When we were designing the Astrophysics missions for the game, we had to explore the various ways star charts were presented. The player is viewing all of this as SAM, an AI that is having a bit of an existential crisis, and so the natural direction was to go digital - a fully digital map, created as a scientific 3D model or something. But much like in Stories Untold, there is something about analog being presented as being 'more honest'. That the best, most accurate or truest form of something is not the digital form, but rather something made out of chemicals and light. Like it's somehow tamper-proof.

"The gameplay action we wanted players to do here was literally scour this image for their targets, manually, to emphasise how SAM is no longer relying on his technical aspects and behaving more like a human. We don't have a search bar in our heads, we look for patterns or variations, things that spark interest. Computers don't do that, but now SAM is - so that gameplay action alone is speaking to SAM's state of mind. Those aspects, plus the welcome analog aesthetic in a very digital UI, took us in that direction.

"The other aspect of POSS that really appealed to us was that it's historical. This is a map that's been around for decades and is still considered accurate by our space agencies in 2026 at the time of the game. An easter-egg/trophy in the game (spoilers) is that you can see a hexagon in the map as an anomaly. This tiny detail, considered with the fact that the plates have been around so long, meant that the hex's have been around for a long time too, watching. I'm not sure anyone puts all that together or if we're being too obtuse, but it's fun to take these real life concepts and weave them into our world."

For years, the night sky could be found arranged neatly in a bunch of folders stacked in a huge system of filing cabinets in research department libraries around the world. The night sky captured as a set of images called the Palomar Observatory Sky Survey, or POSS for short.

The POSS is a series of almost 2000 photographic plates of the stars, taken on the 48-inch Schmidt telescope at Palomar Observatory, largely over the course of the 1950s. The first photographic plate was exposed in November 1949 and the last in December 1958. Each 14-inch plate shows an area of the sky "that looks about as big as your fully outstretched hand held at arm's length," explains the astronomer Mike Brown, writing about POSS with obvious fondness in his book, How I Killed Pluto - and Why it had it Coming. (Amongst other things, Brown discovered Eris, a Kuiper Belt object that ultimately led to Pluto being reclassified as a dwarf planet. His book is an absolute delight.)

Brown has used the 48-inch Schmidt in his own work, and he also writes at length about what it's actually like to explore the POSS. "As a graduate student, I had been instructed in [its] arcane mysteries," he says. "First, you go to the astronomy library and open the big cabinets; then, based on the sky coordinates of where you want to be looking, either you find the library ladder and climb to the top (if you're looking in the far north), or you sit on the floor (for the farthest southern objects), or, if you are fortunate enough to be looking for something directly overhead, you can stand comfortably and look straight ahead."

I love this idea, that the order of the firmament is translated in some way to filing cabinets. But of course that's just the start. Hopefully, Brown continues, your prints are where they're actually meant to be and haven't been misfiled. Even once you find what you're after, 14 inches of space is pretty busy, so you have to bust out the jeweler's loupe to find what you're looking for.

Technology! Once you've found the thing you want, using a jeweler's loupe to peer at a photograph taken in the 1950s, you would pull out a "custom-built" Polaroid to snap a picture of the area you were after. "That Polaroid print is now your personal road map," explains Brown, who says that for years astronomers would carry these Polaroids with them wherever they went in the world, a way of fixing meaning to the seemingly random scattering of stars you see whenever you look through a telescope. There's something terribly romantic about this - although I can imagine the rage inspired by the misfiling of images. Something in amongst the clutter of analogue solutions gives the business of studying the stars something of the buccaneering thrill of a hunt for treasure.

Hundreds of crucial discoveries have been made using POSS, which is now available online. Scanning through images on Google, I am still arrested by the strangeness of space, not least because the POSS negatives show stars as points of darkness against a bright sea of light. There is just so much of this stuff, so many times and distances and sizes of objects captured, so much of what we can no longer see overhead because of light pollution, and possibly never could because, good as our eyes are, they are not a 48-inch Schmidt.

More than anything, though, I love that the POSS makes something we all know pretty well - the night sky - seem fresh and exciting. And for years it stored all its secrets in a manner that meant just getting to them was a bit of an adventure in itself.

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