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Comment by nate_meurer | Hacker News Reader

To me, the coolest thing about this story is the telescope that was used to find this galaxy. It's literally a bunch of off-the-shelf Canon telephoto lenses stuck together on a metal frame, each with a camera sensor, with coordinated aim and focus.

Apparently, some of the newer Canon lenses have a newfangled anti-reflective coating with unprecedented performance. So some enterprising Canucks said, "you know, maybe we can buy a bunch of those and tape them together and make a world-class scientific instrument, eh?" And then they fucking did it.

That there is the DIY hacker spirit in broad daylight. It's so awesome I can barely stand it.

You can read about it here, which found via Phil Plait's excellent blog: http://www.dunlap.utoronto.ca/instrumentation/dragonfly/

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> a bunch of off-the-shelf Canon telephoto lenses stuck together on a metal frame

That's an interesting remark. It's hard to beat mass production. As number produced skyrocket to the millions, it's difficult that a custom device has the resources that a mass marketed device has.

That's why millionaires have the same phone that you, the military use Xbox 360 controllers in their submarine's periscopes and COTS supercomputers are common.

https://en.wikipedia.org/wiki/Beowulf_cluster

https://www.quora.com/What-smartphone-do-tech-billionaires-u...

"US Navy submarines are getting Xbox 360 controllers to control their periscopes" https://www.theverge.com/2017/9/19/16333376/us-navy-military...

In fact, a whole generation of HPC students and scientists write codes for consumer graphics cards (GPGPU). All of this only because they are so cheap.

I think that the most powerful thing is that they offer a low point of entry. You can start for pretty near free, but for less than £100k you can build a differentiating capability and start contributing to knowledge... vs traditional instruments where the onramp starts at £millions and goes from there.

Thank you! Never heard of the term "Beowulf cluster". Sad to see the Wikipedia page never mention good old Linda, which was developed precisely to allow collaboration in heterogeneous systems.

https://www.nytimes.com/1992/01/19/business/david-gelernter-...

It's really hard for me to figure out if you were sarcastic or not with your "never heard of the term"? You must be either young or never visited slashdot for it not to be sarcasm. It was a running joke in slashdot on every comment section to have a Beowulf cluster of whatever was mentioned in the article.

Not sarcastic at all, just a young-ish person who never used slashdot that much.

We're just getting old - https://trends.google.com/trends/explore?date=all&q=beowulf%...

400mm f2.8 lenses aren't made in the millions. Tens of thousands probably. The lenses used in this telescope cost $8k retail and they use 8 per. Not exactly cheap but surely much lower cost than typical astronomical big iron. Astronomy RAID :)

> Now if the controls break, “I can go to any video game store and procure an Xbox controller anywhere in the world, so it makes a very easy replacement,” Senior Chief Mark Eichenlaub told The Virginian-Pilot.

I get his point but that sounds hilarious. "Hey guys, could we surface for a moment, I need to visit the North Korean/Russian/Antarctic Gamestop for a moment"

"Guys, if you head west now, we can intercept our shipment from PlayAsia by 0700."

I think your link is actually the more relevant one for this story on hn.

Improves the bokeh as well ;)

That's very cool! Although wouldn't the UV filter coating on commercial lenses be counter productive? Assuming they are capturing this stuff full (IR to UV) spectrum...

UV filters are generally not incorporated into lenses. Typically you have to use a screw-on filter for this, and this is only needed for film photography. On digital sensors, the sensor contains the filter, usually some sort of Bayer filter that also blocks UV.

The fluorite lens elements that Canon uses are desirable not just for their low refractive index, but also precisely because they are highly transparent in the IR and UV range. The 400mm used in this particular array uses two fluorite elements, and is one the main reasons it's suitable for this application.

"To me, the coolest thing about this story is the telescope that was used to find this galaxy."

Uh, we just found out a new principle on the large scale organization of matter in the known universe. The method is surely inspirational, but I really have to question your statement that the method of discovery credits more merit than the discovery itself.

Relax. It's just, like, my opinion man.

Sure, sorry, you did state "to me". English is not my native language and nuances sometimes escape me. The jury rigged ground based telescope is cool.

No worries. Just so you know, I'll take any opportunity to deliver a Big Lebowski reference: https://www.youtube.com/watch?v=QsogswrH6ck

Consider yourself warned.

That is an engineering mindset. I was confused when I first read a review of the "Apollo 13" movie that said engineers think the real heroes of the crises were the engineers on the ground - who else would someone think was a hero? Oh yeah, the astronauts who were risking their lives.

I didn’t even know that dark matter was anything more than theoretical.

That depends on how ready you are to dismiss the existing observational evidence for it. While it's by no means proven to exist, it's not something predicted by theory, so it's unfair to call it that. Supersymmetry, for example, is purely theoretical; whereas dark matter is a response to observations that contradict theory.

> we just found out a new principle on the large scale organization of matter in the known universe.

Not really, because we've already knew that and observed it before in the bullet galaxy. This is just a 2nd observation (although it is interesting in the ways it's different).

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