May 7, 2021: Waiting for the Grayline – Earth Science Picture Of the Day – a service of USRA (Suggested by Gary WA2JQZ, May 15, 2021) Note: The significance of the D-Layer disappearing at the terminator is that layer attenuates (absorbs the energy of) the radio signals, especially the lower frequencies. At sunrise and sunset the lower altitude D-Layer is in Earth’s shadow, and so disappears because it doesn’t become ionized by the sunlight. However, the higher altitude F-Layer is still in sunlight, is getting ionized by the Sun, and therefore refracts signals back to Earth just as in daytime. In other words, the signals lose less energy in such conditions, and can propagate farther as they “skip” up and down to the ionosphere and back to Earth, traveling across the Earth.
Craft traveling beyond solar system detects hum emanating from deep space (koaa.com) (Suggested by Gary WA2JQZ, May 13, 2021)
Lunar Crater Radio Telescope: Illuminating the Cosmic Dark Ages (nasa.gov) (Suggested by Gary WA2JQZ, May 7, 2021)
SPRITES (Recommended by Gary Agranat WA2JQZ, April 9, 2021.)
Citizen scientist driven by the need to discover | Local News | santafenewmexican.com (October 19, 2020). Thomas Ashcraft was a speaker at the Society of Amateur Radio Astronomers (SARA) Western conference at the beginning of April 2021. He is an amateur astronomer near Santa Fe, NM, and he spoke with us about his work photographing sprites.
Sprites are electromagnetic discharges above very strong thunderstorms, which reach up through the Earth’s mesosphere to the ionosphere. The pulses last for a few thousandths of a second, so the eye does not easily catch them. But cameras can. These had been noticed for a while, but only got serious attention when an orbiting space crew confirmed them. Now they are a new frontier in atmospheric science.
Thomas lives in what is called the Rio Grande Research Corridor, and he exchanges data and information with institutions there. The Sandia National Labs gave him a camera, originally designed for satellites to photograph nuclear explosions, which he uses to monitor sky phenomena like sprites and meteors. He has that coupled with a receiver. With that, he has determined that sprites create similar effects on radio signals as meteor scatter. He has correlated detecting distant over-the-horizon VHF signals with sprites.
The above link is a profile about Thomas and his work from a local newspaper. It includes an 8 minute video (linked below). He also has a website: http://heliotown.com/. –