7 research outputs found
Demonstrating the Principles of Aperture Synthesis with TableTop Laboratory Exercises
Many undergraduate radio astronomy courses are unable to give a detailed
treatment of aperture synthesis due to time constraints and limited math
backgrounds of students. We have taken a laboratory-based approach to teaching
radio interferometry using a set of college-level, table-top exercises. These
are performed with the Very Small Radio Telescope (VSRT), an interferometer
developed at the Haystack Observatory using satellite TV electronics as
detectors and compact fluorescent light bulbs as microwave signal sources. The
hands-on experience provided by the VSRT in these labs allows students to gain
a conceptual understanding of radio interferometry and aperture synthesis
without the rigorous mathematical background traditionally required.
The data are quickly and easily processed using a user-friendly data analysis
Java package, VSRTI\_Plotter.jar. This software can also be used in the absence
of the equipment as an interactive computer activity to demonstrate an
interferometer's responses to assorted surface brightness distributions. The
students also gain some familiarity with Fourier transforms and an appreciation
for the Fourier relations in interferometry using another Java package, the
Tool for Interactive Fourier Transforms (TIFT). We have successfully used these
tools in multiple offerings of our radio astronomy course at Union CollegeComment: 10 pages, ISE 2 A "International Symposium on Education in Astronomy
and Astrobiology
Freshwater invertebrate responses to fine sediment stress A multi-continent perspective
Excessive fine sediment (particles <2 mm) deposition in freshwater systems is a pervasive stressor worldwide. However, understanding of ecological response to excess fine sediment in river systems at the global scale is limited. Here, we aim to address whether there is a consistent response to increasing levels of deposited fine sediment by freshwater invertebrates across multiple geographic regions (Australia, Brazil, New Zealand and the UK). Results indicate ecological responses are not globally consistent and are instead dependent on both the region and the facet of invertebrate diversity considered, that is, taxonomic or functional trait structure. Invertebrate communities of Australia were most sensitive to deposited fine sediment, with the greatest rate of change in communities occurring when fine sediment cover was low (below 25% of the reach). Communities in the UK displayed a greater tolerance with most compositional change occurring between 30% and 60% cover. In both New Zealand and Brazil, which included the most heavily sedimented sampled streams, the communities were more tolerant or demonstrated ambiguous responses, likely due to historic environmental filtering of invertebrate communities. We conclude that ecological responses to fine sediment are not generalisable globally and are dependent on landscape filters with regional context and historic land management playing important roles
Demonstrating the Principles of Aperture Synthesis with Table- Top Laboratory Exercises
Many undergraduate radio astronomy courses are unable to give a detailed treatment of aperture synthesis due to time constraints and limited math backgrounds of students. We have taken a laboratory-based approach to teaching radio interferometry using a set of college-level, table-top exercises. These are performed with the Very Small Radio Telescope (VSRT), an interferometer developed at the Haystack Observatory using satellite TV electronics as detectors and compact fluorescent light bulbs as microwave signal sources. The hands-on experience provided by the VSRT in these labs allows students to gain a conceptual understanding of radio interferometry and aperture synthesis without the rigorous mathematical background traditionally required.
The data are quickly and easily processed using a user-friendly data analysis Java package, VSRTI_Plotter.jar. This software can also be used in the absence of the equipment as an interactive computer activity to demonstrate an interferometer’s responses to assorted surface brightness distributions. The students also gain some familiarity with Fourier transforms and an appreciation for the Fourier relations in interferometry using another Java package, the Tool for Interactive Fourier Transforms (TIFT). We have successfully used these tools in multiple offerings of our radio astronomy course at Union Colleg
Demonstrating the Principles of Aperture Synthesis with Table-Top Laboratory Exercises
Many undergraduate radio astronomy courses are unable to give a detailed treatment of aperture synthesis due to time constraints and limited math backgrounds of students. We have taken a laboratory-based approach to teaching radio interferometry using a set of college-level, table-top exercises. These are performed with the Very Small Radio Telescope (VSRT), an interferometer developed at the Haystack Observatory using satellite TV electronics as detectors and compact fluorescent light bulbs as microwave
signal sources. The hands-on experience provided by the VSRT in these labs allows students to gain a conceptual understanding of radio interferometry and aperture synthesis without the rigorous mathematical background traditionally required.
The data are quickly and easily processed using a user-friendly data analysis Java package, VSRTI_Plotter.jar. This software can also be used in the absence of the equipment as an interactive computer activity to demonstrate an interferometer’s responses to assorted surface brightness distributions. The students also gain some familiarity with Fourier transforms and an appreciation for the Fourier relations in interferometry using another Java package, the Tool for Interactive Fourier Transforms (TIFT). We have successfully used these tools in multiple offerings of our radio astronomy course at Union Colleg