Go Back   Physics Help Forum > College/University Physics Help > Advanced Optics

Advanced Optics Advanced Light and Optics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Aug 26th 2015, 10:58 AM   #1
Member
 
kelsiu's Avatar
 
Join Date: Jun 2014
Posts: 67
Why array of telescope is used?

To increase the resolution of an instrument, smaller wavelength and larger aperture is desirable. It is mentioned in some textbooks that the "effective" diameter of a telescope can be increased by using arrays of smaller telescopes. I just wonder why it is possible because every telescope is separated.
kelsiu is offline   Reply With Quote
Old Aug 26th 2015, 12:08 PM   #2
Physics Team
 
ChipB's Avatar
 
Join Date: Jun 2010
Location: Naperville, IL USA
Posts: 2,271
To increase resolution the images that each telescope obtains must be precisely aligned and then combined. This is relatively easy to do with radio telescopes, as the signals from each are electrical in nature and so can be combined electronically. It is much more difficult to do this with optical telescopes, as it requires very precisley aligned system to mirrors to bring the images from all the scopes to a point where they can be combined. For some examples, see: https://en.wikipedia.org/wiki/Astron...interferometer
ChipB is offline   Reply With Quote
Old Aug 26th 2015, 10:35 PM   #3
Member
 
kelsiu's Avatar
 
Join Date: Jun 2014
Posts: 67
I think as they are using arrays of telescopes they certainly get better resolutions, I am just not quite sure about the effect of diffraction on smaller apertures.

If I look through a circular tube with diameter D which consists of many smaller tubes inside, like a bundle of drinking straws, and if the diameter of these drinking straws are small compared to the wavelength of visible light, can we still get the same resolution as looking through the big tube with diameter D but no drinking straws inside?
kelsiu is offline   Reply With Quote
Old Aug 27th 2015, 03:11 AM   #4
MBW
Senior Member
 
MBW's Avatar
 
Join Date: Apr 2008
Location: Bedford, England
Posts: 668
Size isn't everything

There are two reasons for bigger telescopes being better,
One is Resolution, the other is for collection of as many of the rare photons from distant sources as possible.
Given a number of photons per metre arriving from the distant object, a large Collecting Area will obviously catch more photons.
The resolution is more subtle and is based on how far apart the most distant points on the telescope are.

Building a single huge telescope presents practical mechanical problems.

However, with (very) precise alignment, the photons from two or more telescopes can be combined to give a resolution based on how far apart the most distant points on the array of telescopes are.
__________________
You have GOT to Laugh !
MBW is offline   Reply With Quote
Reply

  Physics Help Forum > College/University Physics Help > Advanced Optics

Tags
array, telescope



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Physics Numerical (Galilean Telescope) Dr. Mrs Arooj Muneer Light and Optics 4 Jan 2nd 2010 09:18 PM
Astronomical telescope hana1 Light and Optics 10 Jul 27th 2009 09:33 PM
Telescope werehk Light and Optics 1 May 24th 2008 10:08 AM


Facebook Twitter Google+ RSS Feed