Hello, can anyone tell me what these cylindrical structures are?

 

Hello,

It looks like a parabole antenna with an extra reflector.
http://www.radio-electronics.com/info/antennas/parabolic/parabolic-reflector-dish-feed-systems.php

Bertus

 

the cylinders are to shield the antenna from sources coming from the side. that is an array of radio telescopes.

 

I'll take a WAG.
It looks like a Offset Gregorian antenna.
http://www.seti.org/seti-institute/project/technical-overview/details/technical-overview

Better picture.

A metal shroud connects the bottom half of the sub-reflector to the bottom of the primary to deflect ground spillover. The inclusion of the shroud is important in achieving lower system temperatures.

http://arxiv.org/pdf/0904.0762.pdf

 

Check out Allen Telescope Array:

http://en.wikipedia.org/wiki/Allen_Telescope_Array

 

Thank's nsaspook, I got it.
I read bertus' link.......looked at my pic again........and was still puzzled.
Then I saw your pic and realized that there was a cap on the end. I thought the structure was open, I didn't see reflector.
Thank you gentlemen.