The red line show the approximate path traced by the field of view of the telescope during observations. The coordinate of Saturn at the time of it’s passing is shown on top left corner. Credit: Pranshu Mandal et al., 2016.
A team of undergraduates from the Indian Institute of Science Education and Research (IISER) at the College of Engineering in Trivandrum, India, has designed and constructed a portable college-level radio telescope for amateur radio astronomers. The students have developed a radio telescope and also data analysis tools that are affordable for schools and colleges, combining low cost and ubiquitous accessibility of resources needed to build these instruments.
“The telescope is dedicated to amateur radio astronomers ranging from high school students to college graduates,” Devansh Agarwal. While large radio telescopes are needed to detect radio waves from astronomical sources, the students have shown that a small one could also make great discoveries in the field of radio astronomy. A small radio telescope designed by the team was able to measure the brightness temperature of the sun. The scientists also demonstrated the usefulness of their telescope by detecting point sources such as Saturn and extended sources such as the galactic arm of the Milky Way.
Block diagram of the radio telescope setup. Credit: Pranshu Mandal et al., 2016.
The team revealed that by performing drift scans, the brightness temperature of the sun was calculated to near 10,000 K with a maximum error of 3.23%. Sources like Saturn and the galactic arm were confirmed by correlating the time of arrival of the source signal in the field of view of the telescope with the predicted times via open-source planetarium software Stellarium, based on the team’s pointing. The flux received from the sources was calibrated against the standardized data from various geostationary satellites.
The radio telescope consists of a satellite antenna, a satellite signal meter called ‘satellite finder’ and a microcontroller board named Arduino Uno. The antenna has a 68 cm parabolic dish reflector and a low noise block (LNB) which receives the radio signal from the satellite reflected by the dish and amplifies it. There is also a set-top box that powers the satellite finder and the LNB. Satellite finder is used for orienting satellite dishes towards geostationary satellites.
“We have used a commercially available analog satellite finder (GC SF-02). Such a device acts as a square law detector and is used to read directly the intensity,” the team wrote in the paper.
Arduino Uno is a microcontroller board with a 10 bit analog to digital converter. It enables digitizing the intensity from the satellite finder at 10Hz sampling rate. The tool is connected to a personal computer.
“In India, this telescope cost was less than $75. However, it is highly dependent on rates of components available at your place,” Agarwal said. The project also leaves a lot of space for future improvements, eg an increase in sensitivity would offer the opportunity to look at many other sources than just the sun.
“All-sky visibility maps can be generated at a rudimentary level that would make one familiar with a bigger part of the radio sky,” the team concluded.
http://arxiv.org/abs/1601.02982 http://phys.org/news/2016-02-students-everyday-radio-telescope.htmljCp
Recent Comments