Panoramic optical and near-infrared SETI instrument: prototype design and testing

The Pulsed All-sky Near-infrared Optical Search for ExtraTerrestrial Intelligence (PANOSETI) is an instrument program that aims to search for fast transient signals (nano-second to seconds) of artificial or astrophysical origin. The PANOSETI instrument objective is to sample the entire observable sky during all observable time at optical and near-infrared wavelengths over 300 - 1650 nm$^1$. The PANOSETI instrument is designed with a number of modular telescope units using Fresnel lenses ($\sim$0.5m) arranged on two geodesic domes in order to maximize sky coverage$^2$. We present the prototype design and tests of these modular Fresnel telescope units. This consists of the design of mechanical components such as the lens mounting and module frame. One of the most important goals of the modules is to maintain the characteristics of the Fresnel lens under a variety of operating conditions. We discuss how we account for a range of operating temperatures, humidity, and module orientations in our design in order to minimize undesirable changes to our focal length or angular resolution.Comment: 12 pages, 8 figures, 1 tabl

Trail Mapping from Space: New Recreation Mapping at Bogus Basin Ski Area

Research Question: Can a comprehensive, accurate, and detailed map of recreational trails be produced without stepping foot in the field? Remote sensing is reconnaissance at a distance (Colwell, 1966). Mapping is a three step process: 1.) basemap assembly, 2.) cartographic interpretation, 3.) review & correction. While a simple concept, remote sensing has traditionally been the left to the experts due to the high skill set and specialized computing equipment required to complete even the most rudimentary data preparation and processing tasks. Today, Google Earth, the National Agricultural Imagery Program (1m NAIP), global 30m digital elevation data (DEM), desktop ArcGIS, and user-friendly graphics packages (Adobe Creative Suite) have revolutionized the mapping process for students and other non-professionals. For this project students in GEOG 361/461 Remote Sensing collaborated with Bogus Basin Ski Area to completely remake the recreational map of the Shafer Butte-Mores Mountain-Stack Rock area. Students were successful in producing a.) an updated and expanded mountain biking/hiking trails map, b.) two ultimate frisbee course maps, c.) a nordic skiing/snowshoe trail map, and d.) 3D video flythrough guided tours of popular trail loops using Google Earth and Final Cut Pro. All data layers were migrated to modern GIS formats for improved storage and retrieval. The final, print-ready maps were assembled in Adobe Illustrator to simplify future updates and print production. The completed maps were reviewed by Bogus Basin field crews and staff. Comments were very positive and edits minimal. The maps were accurate and useful to on-mountain professionals. This was the first major cartographic project for nearly all students involved

Panoramic SETI: overall focal plane electronics and timing and network protocols

The PANOSETI experiment is an all-sky, all-the-time visible search for nanosecond to millisecond time-scale transients. The experiment will deploy observatory domes at several sites, each dome containing ~45 telescopes and covering ~4,440 square degrees. Here we describe the focal-plane electronics for the visible wavelength telescopes, each of which contains a Mother Board and four Quadrant Boards. On each quadrant board, 256 silicon photomultiplier (SiPM) photon detectors are arranged to measure pulse heights to search for nanosecond time-scale pulses. To simultaneously examine pulse widths over a large range of time scales (nanoseconds to milliseconds), the instrument implements both a Continuous Imaging Mode (CI-Mode) and a Pulse Height Mode (PH-Mode). Precise timing is implemented in the gateware with the White Rabbit protocol

Panoramic SETI: on-sky results from prototype telescopes and instrumental design

The Panoramic SETI (Search for Extraterrestrial Intelligence) experiment (PANOSETI) aims to detect and quantify optical transients from nanosecond to second precision over a large field-of-view (∼4,450 square-degrees). To meet these challenging timing and wide-field requirements, the PANOSETI experiment will use two assemblies of ∼45 telescopes to reject spurious signals by coincidence detection, each one comprising custom-made fast photon-counting hardware combined with (f/1.32) focusing optics. Preliminary on-sky results from pairs of PANOSETI prototype telescopes (100 sq.deg.) are presented in terms of instrument performance and false alarm rates. We found that a separation of >1 km between telescopes surveying the same field-of-view significantly reduces the number of false positives due to nearby sources (e.g., Cherenkov showers) in comparison to a side- by-side configuration of telescopes. Design considerations on the all-sky PANOSETI instrument and expected field-of-views are reported

Panoramic SETI: Program Update and High-Energy Astrophysics Applications

Optical SETI (Search for Extraterrestrial Intelligence) instruments that can explore the very fast time domain, especially with large sky coverage, offer an opportunity for new discoveries that can complement multimessenger and time domain astrophysics. The Panoramic SETI experiment (PANOSETI) aims to observe optical transients with nanosecond to second duration over a wide field-of-view ($\thicksim$2,500 sq.deg.) by using two assemblies of tens of telescopes to reject spurious signals by coincidence detection. Three PANOSETI telescopes, connected to a White Rabbit timing network used to synchronize clocks at the nanosecond level, have been deployed at Lick Observatory on two sites separated by a distance of 677 meters to distinguish nearby light sources (such as Cherenkov light from particle showers in the Earth's atmosphere) from astrophysical sources at large distances. In parallel to this deployment, we present results obtained during four nights of simultaneous observations with the four 12-meter VERITAS gamma-ray telescopes and two PANOSETI telescopes at the Fred Lawrence Whipple Observatory. We report PANOSETI's first detection of astrophysical gamma rays, comprising three events with energies in the range between $\thicksim$15 TeV and $\thicksim$50 TeV. These were emitted by the Crab Nebula, and identified as gamma rays using joint VERITAS observations.Comment: 9 pages, 5 figures, SPIE Astronomical Telescopes + Instrumentation conference, 2022, Montr\'eal, Qu\'ebec, Canad

Glycerol kinase from Escherichia coli and an Ala65→Thr mutant: the crystal structures reveal conformational changes with implications for allosteric regulation

AbstractBackground: Glycerol kinase (GK) from Escherichia coli is a velocity-modulated (V system) enzyme that has three allosteric effectors with independent mechanisms: fructose-1,6-bisphosphate (FBP); the phosphocarrier protein IIAGlc; and adenosine nucleotides. The enzyme exists in solution as functional dimers that associate reversibly to form tetramers. GK is a member of a superfamily of ATPases that share a common ATPase domain and are thought to undergo a large conformational change as an intrinsic step in their catalytic cycle. Members of this family include actin, hexokinase and the heat shock protein hsc70.Results: We report here the crystal structures of GK and a mutant of GK (Ala65→Thr) in complex with glycerol and ADP. Crystals of both enzymes contain the same 222 symmetric tetramer. The functional dimer is identical to that described previously for the IIAGlc–GK complex structure. The tetramer interface is significantly different, however, with a relative 22.3° rotation and 6.34 å translation of one functional dimer. The overall monomer structure is unchanged except for two regions: the IIAGlc-binding site undergoes a structural rearrangement and residues 230–236 become ordered and bind orthophosphate at the tetramer interface. We also report the structure of a second mutant of GK (IIe474→Asp) in complex with IIAGlc; this complex crystallized isomorphously to the wild type IIAGlc–GK complex. Site-directed mutants of GK with substitutions at the IIAGlc-binding site show significantly altered kinetic and regulatory properties, suggesting that the conformation of the binding site is linked to the regulation of activity.Conclusions: We conclude that the new tetramer structure presented here is an inactive form of the physiologically relevant tetramer. The structure and location of the orthophosphate-binding site is consistent with it being part of the FBP-binding site. Mutational analysis and the structure of the IIAGlc–GK(IIe474→Asp) complex suggest the conformational transition of the IIAGlc-binding site to be an essential aspect of IIAGlc regulation