The SRT is a small telescope that provides an introduction to radio astronomy instrumentation and radio astronomical observing techniques to undergraduate student and faculty. Several projects that span topics from instrument evaluation and calibration as well as scientific applications for the SRT are provided below. The projects are divided into three sections - the first set consist of instrument evaluation projects, the second contains adescription of solar observations that can be performed with the system and the final section contains a description of the observations of the hydrogen line.
Evaluate radiometer performance
A) Measure system temperature using vane calibration
- check at various frequencies in 1420 MHz radio astronomy band.
Student Lab Exercise: Measure System Temperature Using a Vane Calibrator
B) measurement of the SRT antenna half-power beamwidth (HPBW) using the sun as a signal source
Student Lab Exercise: Measure Antenna Beamwidth Using the Sun
C) Measure aperture efficiency using automated on/offs on Cas A, Moon and Cygnus X
Student Lab Exercise: Measure Aperture Efficiency
Student Lab Exercise: Measure SRT Sensitivity
Student Lab Exercise: SRT Receiver Tests
Student Lab Exercise: Measure the Beam Efficiency Using Standard Hydrogen Line Calibration
SRT continuum flux calibrators
| Source | Flux density Jy | Expected Ta K | Comments |
|---|---|---|---|
| Moon | 710 | 1 | Very weak |
| Cassiopeia A | 2000 | 1.5 | 7.5 ft dish - 50% efficiency |
| Cygnus X | ~5000 | 7 | Extended |
| Sun | 2×105 - 2×106 | 264 - 2640 | Variable |
SRT Sun Map: PDF, PostScript
Solar observations
A) Measure the Sun's flux density. - A time history of the 28 day solar rotation would be especially interesting and can provide evidence for the rotation period of the Sun. This figure shows such a plot - the blue points with the error bars are the flux values from the SRT and the pink points are from the NOAA site given below.
Daily solar radio flux data can be obtained from the NOAA/NWS Space Weather Prediction Center
B) During periods of high solar activity the SRT can be used to detect radio flares from the Sun.
Sample Results: Daily Solar Observations with the SRT, PDF
Galactic hydrogen line project
A) Measurement of the Galactic Rotation Curve can be achieved by observing hydrogen lines at different points along the Galactic plane. The rotational curve can be created by plotting the maximun velocity observed along each line of sight versus the distance of this point from th Galactic center.
Student Lab Exercise: Galactic Rotation Curve, PDF
B) Map the sky in 21 cm H I emission. The entire sky can be mapped in 24 hours with about 10 seconds integration per beam. A deeper, more sensitive survey can be made by parking the antenna at one declination for 24 hours and letting the earth's rotation map out one swath each day. With the 4 degree beamwidth this will take more than a month to cover the sky visible from the Boston area.