OVRO GEMS COURSE - Summer 2004

Messages from Space

B. Schuck, A. Beasley, M. Hodges, A. Mercer, L. Dawson


A partnership between the California Institute of Technology/Combined Array for Research in Millimeter-wave Astronomy Project and the Valentine Eastern Sierra Reserve/Sierra Nevada Aquatic Research Laboratory has been formed to provide an elementary and middle school two-week summer science course for students in Inyo and Mono counties. The goals of this course:


A website describing the first year of the program, the curriculum and the coursework can be found at GEMS2003.

GEMS2004:

Over the past year we implemented a new telescope control and data acquisition system for the 40-m, and upgraded the experiments. A screenshot of the new observing system is shown below:
control screen
SETI: Using a Measurement Computing PCI-DA4020 data acquistion card and their Softwire visual programming environment we are now able to process 2 MHz of bandwidth in near real-time. A Windows PC hosted the card, which sampled the radio signals from the receiver (after downconversion) and sent them over ethernet to a Linux PC. This PC autocorrelated the data using the FFTW library routines to produce a 1-Hz resolution spectrum.  An example spectrum is shown below.  The overall shape of the spectrum is an artifact of the receiving system (we haven't implemented position differencing yet). 


HR2250



We broke the students up into groups of three; one controlling the telescope and data acquisition, one making notes in the 40-m log book, and the third watching. Each student observed two stars, then swapped position. If the spectrum looked strange or interesting we repeated the observation. During the observations we walked over  to the control building and turned on a 1-W simple dipole transmitter briefly to see what a real SETI signal might look like:
1-W transmitter
For interest, a spectrum of W3 showing the OH maser:


W3


Solar Scan: A new interface for the solar scan experiment was constructed using the Softwire graphics modules to provide a better understanding of the experiment; at the same time a paper chart recording was made (which the students wrote times on with a marker).  After the observing, the students measured the time of the scan on the paper, we averaged the results and derived the angular diameter of the Sun. A typical scan is shown below.

solar scan


The red trace is the total power detected from the Sun  (128 MHz bandwidth centered at 1662 MHz). To begin the observation we pointed the telescope in front of the Sun, disabled the telescope drives and let the Sun drift through the primary beam (the large peak). Moving the telescope in front of the Sun meant moving quickly past it again (causing the little peaks).

Telescope Control:  Using the IP socket access routines integrated into the 40-m control system (many thanks to Martin Shepard and Tim Pearson) we are now able to guide the telescope from any PC behind the firewall. This enabled us to put both telescope control and data acquisition onto one screen (simplifying the interface for the students). Softwire provided a good graphical environment to work in, with a few bugs.

Activities:

Other activities during the two weeks included tours of different parts of the Owens Valley Radio Observatory, including the Millimeter Array and the NRAO Very Long Baseline Array OV station. There was an overnight stay organized to allow optical observing with Ron Smith and Rich Garner (local astronomy club members; Ron gave an excellent talk to the class). We showed "The Arrival" on the side of the telescope tower again; poor Charlie Sheen being hassled by the aliens whose knees bend the wrong way.







For details of how to sign up to participate in the GEMS course in 2005, please go to

 http://vesr.ucnrs.org

Or e-mail ldawson@msi.ucsb.edu


Created: Jul052005 TJB