NASA Takes Step Forward In Planet Finding

Spy der Mann wrote to mention a piece at Physorg.com about a major breakthrough in planet finding. From the article: "On a crystal clear, star-filled night at Hawaii's Keck Observatory in Mauna Kea, NASA engineers successfully suppressed the blinding light of three stars, including the well-known Vega, by 100 times. This breakthrough will enable scientists to detect the dim dust disks around stars, where planets might be forming. Normally the disks are obscured by the glare of the starlight. Engineers accomplished this challenging feat with the Keck Interferometer, which links the observatory's two 10-meter (33-feet) telescopes. By combining light from the telescopes, the Keck Interferometer has a resolving power equivalent to a football-field sized telescope. The 'technological touchdown' of blocking starlight was achieved by adding an instrument called a 'nuller.' "

Comments

You can do the same thing at home

[Chairboy]

I've replicated the same feat at home using a device I call a "lens cap", except I can significantly beat the 100x reduction of star brightness.

I'll entertain all bids on this technology...

Re:Interferometer?

[MarkRose]

Actually, yes. It uses the interference patterns between the light received at the two (or more) telescopes to give resolution many times that of the individual instruments. http://en.wikipedia.org/wiki/Interferometry

slightly more info

[1fitz2many]

Here's an older press release (with dewar pic) that has a little bit more info. Looks like lab tests were able to provide a null depth of 10^3 vs. 10^2 reported on-sky in the current blurb.

Finally, since I haven't seen a one sentence synopsis, a nulling interferometer does a careful job making the on-axis starlight received by two telescopes interfere destructively, while off-axis light from circumstellar emission passes through the system. This instrument is designed to study dust emission analogous to the zodiacal light in our own solar system.

Re:Interferometer?

[StupendousMan]

> Can this be programmed into cheap telescopes for well known light sources?

    No. The technology required to combine two light beams in
a coherent way is wa-a-a-y more expensive than a "cheap"
telescope. One must be able to control the length of the
two paths of light to a small fraction of wavelength of
the light. In the case of ordinary visible light, that
means "a small fraction of about 500 nm". That's the
hard part :-(

> Is this the answer to light pollution?

    Again, no. If you can perform interferometry, you
can in effect reduce the size of the field of view, if
you wish, and therefore reduce the noise contributed
by background light; but for most purposes, you
still want to see more than just point sources,
which means a reasonable field of view, which
means that there is still plenty of noise from the
background.

    Alas.

Informative links

[DerekLyons]

1. Technical description of the interferometer.
2. A detailed paper (PDF file) on the nuller.