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Yesterday's post about ginormo-scopes led to a question about how a bunch of smaller telescopes can create a simulated big 'scope of much larger diameter. The way this happens is called interferometry, a technique that works by (digitally or optically) combining the images each telescope captures at the same time into a single image. This creates a simulated resolving power (the detail such an image can see) of a telescope with the diameter of the outside edge of the telescope mirror plus the distance between them.

Here's an image that might help explain how this works:

Click the image to see the story.

Aperture synthesis is another way to make a very big telescope out of smaller ones.

Click the image to see the story.

This is not unlike the STEREO mission, which uses two nearly identical space observatories to create a stereoscopic effect: one ahead of Earth in its orbit, the other trailing behind.

Binoculars are also a way to increase resolution, making a pair of 60mm lenses into something with a theoretical resolution of four or five times that diameter... but that requires your brain to do the processing. Mostly such arrangements just increase the "3D" effect and enhance contrast by showing an object from two different angles.

Optics are cool.




( 2 comments — Leave a comment )
Jul. 16th, 2007 10:26 pm (UTC)
See, I actually understand this, when someone walks me through it.

Whether I could walk someone else through it, say in a couple of weeks' time, whole nother question. But - for now - I am better informed and less bewildered than I was. So thank you.
Jul. 17th, 2007 03:07 am (UTC)
Happy to help!
( 2 comments — Leave a comment )