AST460: Assignment 4
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(Sep 28 2012)

1. Practicing Unix:
Log in to one of the classroom computers using your user name and password.
Go to the class main directory: /d/leffe/astro_460/Class_2012
Make here your working directory. 
Now in your working directory make the following sub-directories: 
Data, Scripts, Idl, Reports.

In your working directory make a file called README where you will explain briefly
what each of your sub-directories is for. In the future, please update this file
by adding information about the purpose of various programs/reports you make 
for easy book-keeping.

Copy this file /d/leffe/sstanimi/napoleon/sample_latex.tex 
and place it in your Reports directory. We will use it later in the course.


2. Making Observing Files for the SRT:

2.1. To measure well the telescope beam or radiation pattern, we need to make 
cross-scans in Azimuth and Elevation across a bright radio sources.
Let's use the Sun as our source.

In your Scripts directory, write an observing script to: 
open a data file where all spectra will go, set a central frequency of 1410 MHz and observing mode 1,
point at the Sun, record observations at 21 offset positions in Azimuth ranging from -20 degrees from the
center of the Sun to +20 degrees with a step of 2 degree (this is our Azimuth cut so
all positions will have the same Elevation). Close the observing file.

Now write another observing script with the same parameters but just by doing
the Elevation cut across the Sun. Start at -20 degrees from the
center of the Sun and move up in Elevation by 2 degrees until you reach +20 degrees from
the center.


2.2. Galactic HI script
Open an observing file and set the central frequency to the HI line, use the highest
resolution observing mode.
Pick a position in Galactic coordinates within the Galactic longitude range 
from 20 to 75 degrees and having Galactic latitude of 0 degrees. 
Go to your desired position and integrate for about 300 sec.
Close the observing file and stow the telescope.


2.3. Andromeda
We have not yet tried to detect the HI line from the Andromeda galaxy with the SRT.
Let's write a script to do this!

The radial velocity of Andromeda relative to the Local Standard of Rest (LSR) is -296 km/s.
In our topocentric velocity system, its radial velocity is about -310 km/s.
Similarly to question 2.2, write an observing script we can use to detect Andromeda.
You essentially need to calculate the central frequency you would need to tune the SRT at to detect
Andromeda as its signal will be blue-shifted relative to the rest HI frequency.
Feel free to use the SRT Simulator to test your preducted frequency.


Observing scripts should be named something like blah.cmd .


The assignment is due at the next class meeting. 
Please provide printouts of your observing scripts.