I understand that LIGO can detect something, but how do they know where it came from? How can they register a disturbance in the spectra to a a source? Do they really quickly point a ccd at the sky and hope they captured what happened?
CMB telescopes use microwave antennas (often feedhorns) to direct the electromagnetic radiation onto some kind of detector. In the case of BICEP, the detector is a superconducting bolometer, which senses small temperature changes caused by CMB photons depositing themselves onto a resistive element.
To get data, a CMB telescope is scanned across the sky for several months (or years), and the raw time signals are converted into a map of the microwave sky.
LIGO is an entirely different category of scientific instrument; it is looking for the direct influence of present-day gravitational waves on the motion of terrestrial masses.
The first gravitational wave detectors weren't sensitive enough; there is a second generation (including a more advanced version of LIGO) that is supposed to come online in the next few years.
In parallel, people are also going forward with development for LISA. It had to be scaled back a bit because NASA decided to pull out, but it's still going.
Just as a reason for doing this in parallel. Space based detectors (such as LISA) are sensitive to a different frequency range than ground based detectors such as LIGO and thus to different of astrophysical phenomena [1]
