Archive for May, 2011

Getting the apodizing phase plate out of my tabs

May 12, 2011

Get ready to see lots more exoplanet images soon | Bad Astronomy | Discover Magazine

What the new technique does is steal a bit of light from the core and use it to suppress some of those ripples. It interferes with them, damping them down. It only works on half the image, as you can see: on the right the ripples are obvious, and on the left they are essentially gone. If you’re looking for a planet, it means you have to observe it several times rotating the detector so you can clean up the halo all the way around the star.

Planet hunters no longer blinded by the light

The Steward Observatory team used a machined piece of infrared optical glass about the size and shape of a cough drop to introduce the ripples. Placed in the optical path of the telescope, the APP device steals a small portion of the starlight and diffracts it into the star’s halo, canceling it out.

I really like this because it’s a hack. Astronomers have been trying for hundreds of years to get rid of excess diffracted light, and you can’t do it. You just can’t. But what you can do is get rid of some of it, and shove the rest into parts of the image that you don’t care about looking at. And that turns out to be better than good enough. (Technically, what they’re doing is trading spatial resolution for time, since you have to observe for much longer to image all angles around a star, but that’s OK too. And, as with most things that have thresholds, you’re not going from mediocre signal to slightly better signal, but from no signal to signal at all…)


At last: e-paper that’s actually like paper

May 5, 2011

Video: E Ink Shows Off Rollable, Scrunchable, and Video Screens | Popular Science

These demos show that e-ink displays can be embedded into other materials–the video below shows it sewn right into a bit of Tyvex cloth, the super-tough, paper-like cloth used in shipping envelopes.

It’s easy to see the uses for that kind of thing: Envelopes could be sturdy and reusable, with shippers simply changing the shipping address on the screen rather than tossing the envelopes.

This makes me happy, but what I particularly want to see is the next step: e-ink displays where most of the driver electronics have been separated from the display. Because for the kinds of e-ink applications they’re talking about, you don’t want the display changing a lot, and you don’t want just anybody to be able to change it. For instance, you don’t want the routing or delivery folks at the shipping company to be able to change the label…

Figuring out the right partitioning for this kind of thing is difficult; maybe you could have some kind of scrambling section that would reroute all the rows and columns according to a key known only by authorized people. Or maybe real crypto somewhere. Or just something that measured how much current had been passed through the drivers and encoded it with some kind of checksum…

But none of that is necessary for what I want: a pile of e-paper and a printer that will erase and reprint each sheet whenever I want, so that I can spread out as much reference material as I can see, just like I used to be able to do with books.

A certain naive charm

May 5, 2011

File-Sharers Await Official Recognition of New Religion | TorrentFreak

The church has its own set of axioms, most of which revolve around free access to knowledge and the sharing of information. They include:

# Reproduction of information is ethically right.
# The flow of information is ethically right.
# Remix Spirit is a sacred kind of copying.
# Copying or remixing information conveyed by another person is an act of respect.