This photograph from university photographer, Mark Philbrick shows the BYU 0.9-meter Reflector at the West Mountain Observatory focused on a field near the galactic center during the summer of 2016. The stars of the constellation Scorpius are visible through the lower center portion of the dome slit with the planets Mars (on the right side) and Saturn (just off the left edge) visible. The computer controlled telescope was funded through an NSF grant; AST 0618209.
Group theory provides the most natural parameter set for describing a distorted crystal structure, since a relatively small number of parameters normally exhibit non-zero values. These symmetry modes are also the ideal parameter set for determining a complicated structural distortion and determining its symmetry without prior assumptions. This was demonstrated in a combined x-ray/neutron study of monoclinic room-temperature tungsten oxide.
To uniquely identify the superspace-group (SSG) symmetry of a modulated crystal, one needs a way to test the equivalence of two distinct sets of superspace-group operators. A highly efficient and robust algorithm, which was recently developed for tabulating SSGs, has now been employed to identify the symmetries of each of the (3+2)D and (3+3)D modulated structures published in the literature to date.
Not astronomy! This is actually single-crystal diffuse x-ray scattering from an important industrial isomerization catalyst called mordenite, where the L = 0 plane of reciprocal space was reconstructed using portions from over 1000 CCD X-ray camera images. The broad patches, open diamonds, and star-shaped distributions are clues that reveal a complex architecture of framework defects with implications for this zeolite’s unusual adsorptive and catalytic properties.
This is a mosaic of solar eclipse images secured on May 20, 2012 by Dr. Michael D. Joner. The individual observations were made between 6:59 and 8:06pm MDT a couple of miles northwest of Kanarraville, Utah on the center line of this annular solar eclipse. The entire solar photosphere was not blocked by the passage of the Moon for this eclipse. The result was an annular eclipse due to the fact that the Moon was close to apogee and thus not large enough in the sky to cover the entire Sun. Many areas of southern Utah enjoyed perfect weather in addition to being ideally located to view the eclipse well before sunset.
20 Apr, Today
21 Apr, Saturday
25 Apr, Wednesday
Traci Neilsen, Aaron Vaughn, and Kent Gee et al. recently published an article titled "Level-educed Wavepacket Representation of Mach 1.8 Laboratory-Scale Jet Noise" in 23rd AIAA/CEAS Aeroacoustics Conference (Denver, CO, June 2017), AIAA AVIATION Forum, (AIAA 2017-4049).. Click on the image above to read it.
Moon in the Hyades: Have you seen the Moon lately? On April 18, its waxing sunlit crescent moved through planet Earth's night across a background of stars in the Hyades. Anchored by bright star Aldebaran, the nearby, V-shaped star cluster and complete lunar orb appear in this telephoto image....
This photograph and Description come from NASA's Astronomy Picture of the Day web site.