Observatories
Background
The Angell Hall Small Radio Telescope (SRT) was commissioned in the winter of 2001. It is capable of continuum and spectral line observations in the L-band (1.42 GHz). The SRT was developed at the Haystack Observatory.
The SRT is a standard seven-foot (2.1 meter) diameter satellite television dish mounted on top of a fully motorized Az-El mount. This unique mounting arrangement allows the observer to perform total power measurements and contour mapping. Software has been provided for controlling the antenna and selection of sources. Data reduction can be performed using existing radio astronomy software packages or left as an exercise for the student.
The diameter of the SRT results in a beam width of roughly 5 degrees. The receiver is sufficently good to detect several strong sources (including the sun of course). As the 361 students this year can testify, it is capable of measuring the galactic hydrogen emission, even on a single scan - the galactic rotation curves they derived were based upon 5-minute integrations at ten points along the galactic plane. The frequency resolution of the line receiver is 40 KHz (=> 8 Km/sec).
Operation
The control computer is located in the NW corner of the (original) computer room, and can uniquely identified by the small metal box (the control interface) to the left of the computer. The switch on this box must be turned on before one activates the telescope control program. Access to the control program and interface are obtained by logging into the 'local' machine (not LSA) as srt_user. The password can be obtained by contacting Hugh Aller.
Start up Instructions
The program runs from a 'dos' window.
(To open a dos window go to START -> Run CMD).
In the dos window type: CD C:\JDK\SRT java srt 0 to control the telescope.
To run in simulation mode type: java srt 1 1
The Haystack site has extensive information about the telescope, operating instructions, a tutorial on Radio Astronomy and example labs (such as the galactic rotation lab we tried in Astronomy 361).
Here are some relevent URLs:
SRT Home: http://web.haystack.mit.edu/SRT/index.html
Operations Manual: http://web.haystack.mit.edu/SRT/SRTManual.pdf
Tutorial: http://web.haystack.mit.edu/urei/tutorial.html
Aside from preparing observing scripts (which are some what unforgiving to format errors), the operation of the telescope is quite easy and straight- forward.
We will be adding more labs and examples of observing scripts here in the near future.
