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Science Section => Astrophysics discussion => Topic started by: nichendrix on 03:05:57, 22 April, 2015

Title: How to calculate the area of a multi-telescope systems like VLT?
Post by: nichendrix on 03:05:57, 22 April, 2015
I didn't know how to post it, so this is the closest place I could think of, if it's not appropriate, please feel free to move or close.

How you calculate how many smaller telescopes are necessary to capture an image equivalent to a bigger telescope? Is there a formula for it?

Thanks

Nicholas
Title: Re: How to calculate the area of a multi-telescope systems like VLT?
Post by: chris.bailey on 07:46:02, 22 April, 2015
Nicholas

I don't think arrays like the VLT work quite like that as in interferometer (VLTi) mode there are combinations of some of the main unit telescopes with the smaller auxiliaries. This increases angular resolutions to an incredible degree but I think it only works in the infrared spectrum like this. Most of the work is done with the single unit telescopes.

The main thing about an array of telescopes is the extra speed of data collection.

Chris
Title: Re: How to calculate the area of a multi-telescope systems like VLT?
Post by: Darkstarshado on 08:07:24, 22 April, 2015
Chris is right, the technique is called 'very long baseline interferometry' - wiki link: http://en.wikipedia.org/wiki/Very-long-baseline_interferometry (http://en.wikipedia.org/wiki/Very-long-baseline_interferometry)
Cheers,
--
Rob
Title: Re: How to calculate the area of a multi-telescope systems like VLT?
Post by: Bazzaar on 20:38:43, 22 April, 2015
It depends what you mean by equivalent image.
Bigger scopes capture more light allowing dimmer objects to be seen, they also have better resolution for smaller details.
The light capture is proportional to the area of the mirror and the resolution to the diameter. Area is proportional to diameter squared so doubling a mirror size gives twice the resolution but four times the light.
So you would need four 1m scopes to give the same image as a 2m scope.
Barry
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