Outreach

1. Teaching Research 2011 was the first year that undergraduates used CCD cameras and dedicated processing platforms to complete their own research projects. AST310 gave students outside the physics department the opportunity to gather digital data of the day and night skies. A selection of their results is below. Students Taylor Brandenburg and Tristan Root recorded images of the globular cluster M3 through green and blue filters. The difference in brightness of a given star at these wavelengths is a measure of its surface temperature. They combined the data into a color-magnitude diagram that clearly shows the aging red giants of the cluster. The main sequence stars – those still fusing hydrogen into helium – are too faint to be recorded in two nights of observing. Students in the future will be able to add their data to previous work and eventually go faint enough to find the main sequence. Outreach Since the solar minimum ended two years ago, we have shown the Sun’s disk to over 1,000 children and adults. The solar telescopes we use have filters that are integrated into their design; none of the “safety” is removable. Solar prominences and sunspots are crisply displayed through a filter bandwidth of less than 10Å, centered at Hα. The filter is tunable to accommodate temperature changes inside the telescope. Nelson’s Resort – Crane Lake, MN 20 million light years away in M51 the third supernova in less than 20 years was detected last June by an amateur astronomer. Note that the day that the light curve peaks is wavelength dependent. AST310 student Jarvis Livingston chose to research the feasibility of using off-the-shelf digital cameras and free software to determine the surface temperature of bright stars. His results show that point-and-shoot cameras have focal ratios that are generally too large to record anything but the brightest stars, and that these tend to be statistically anomalous. Also, “hot-pixel” correction algorithms automatically remove faint stars from the image. A Nikon DSLR has color filter placements that give a modest correlation between recorded color and the true surface temperature of a star (right). Undergraduate Zach Jones compared his photographs of the supernova seen in 1054 (which produced the Crab Nebula) with archival images to measure the rate of expansion and therefore the age. He found the age of the nebula to be about 1,000 years (right). Sky & Telescope cover (October 1946) MacAdam Student Observatory Hα image Z. Jones (2011)