WASI Monthly Members Meeting
Monthly members meetings are held at 7:00 PM Eastern time on the second Wednesday of the month at the Bear Branch Nature Center, 300 John Owings Rd. Westminster, MD and online via Zoom. There’s a demo or class at 7:00 PM, followed by the featured guest speaker presentation at 7:30 PM.
Our April 8, 2026 meeting features a talk by Dr. Peter Plavchan who will discuss “The NASA Landolt mission”.
The NASA Landolt mission is a timely PIONEERS program that will provide significant improvement in the accuracy of photometric measurements of absolute stellar fluxes. This will be accomplished with a high accuracy National Institute of Standards and Technology (NIST) calibrated suite of single-mode fiber-fed laser beacons which will be observable from selected ground-based observatory stations. Landolt will improve the photometric accuracy to <0.5% at visible (VIS) and near-infrared (NIR) wavelengths for >60 target stars, improving upon the half-century old techniques that use ground-based blackbodies and calibrated lamps along with model stellar atmospheres and sounding rocket measurements. The Landolt mission will allow us to re-calibrate the brightnesses of millions of stars. Such measurements can only be achieved by a space-based orbiting artificial star, where the physical photon flux is accurately known. Accuracy of absolute flux zero points is now the leading error budget term in the characterization of stars, be they standard stars or exoplanet hosts. Similarly, the accuracy of the ratio of the VIS/NIR absolute flux calibration zero point is the limiting error budget term in the Supernovae (SNe) Ia cosmological constraints on dark energy, a key science goal of the Nancy Grace Roman Space Telescope (Roman) and Vera C. Rubin Observatory (Rubin). Consequently, Landolt will enable the refinement of dark energy parameters, improve our ability to assess the habitability of terrestrial worlds, and advance fundamental constraints on stellar evolution.
Dr Plavchan is an associate professor of Physics and Astronomy at George Mason University, where he is also the Executive Director of George Mason Observatories and the Mason Space Exploration Center. He was formerly an assistant professor at Missouri State University, a research scientist at the NASA Exoplanet Science Institute. He earned his PhD in 2006 from UCLA, and undergraduate degree from Caltech in 2001. His research is on the frequency and formation of exoplanets orbiting low-mass stars, and is an expert with the precise radial velocity technique, particularly at near-infrared wavelengths. He discovered the young transiting planetary system orbiting AU Mic published in Nature in 2020. He is currently PI of the NASA Landolt mission and the HaZE mission concept. He has built instrumentation for the NASA Infrared Telescope Facility, and uses ground-based telescopes world-wide and in space with the Spitzer, Kepler, TESS and James Webb Space Telescope missions.
Meeting ID: 879 7384 1396
Passcode: 965007
Previous Meetings
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