Allen is an amateur astronomer, an IT professional, a podcaster, a father of five growing kids, a barely competent chess player, and the owner and publisher of the Urban Astronomer podcast and website. He has formerly served as Director of the Astrophotography and Citizen Science sections of the Astronomical Society of South Africa. You can find his personal social media feed on Mastodon!
I recently unpacked my mirror for the first time since moving house. I had been working it with #220 grit for what felt like an extremely long time, and was impatient to finish the stage. I ground a few wets, dried the mirror and inspected the surface with bright light and a magnifying glass. Result: Lots of pits, and no way to remember what had been there before. The time had come to try out a trick I recently read … Continue reading →
Space Explorations Technologies (SpaceX) recently won a contract with Iridium Communications Inc. to launch the Iridium NEXT fleet of satellites into space in the largest ever commercial space launch contract with any single entity. Iridium has an existing constellation of satellites which it maintains to provide a satellite phone service with worldwide coverage. This new contract will involve six launches of SpaceX’s Falcon 9 rocket to place 72 Iridium NEXT satellites in orbit, positioned over the globe to provide uninterrupted … Continue reading →
The incident referred to in the buzz surrounding the Hottel Report is probably the most familiar UFO story ever: Roswell. Many books could be written (and they have) on the Roswell incident, on what happened, on what really happened, on what “They” don’t want you to know, and more. It’s been confirmed, debunked, studied, de-debunked, re-debunked and ridiculed. There are so many versions of the truth out there that hardly anybody takes it seriously anymore. Roswell is a cultural phenomenon, … Continue reading →
Last night I made time in my schedule to get in a bit of grinding. Not a lot to say, really, except that I spent about 20 minutes restoring a very thin bevel to the edge of mirror and tool – maybe 1mm, if you’re feeling generous. Time will tell if it’s generous enough, but I don’t want to sacrifice any more aperture than necessary!I then put in about an hour’s grinding with the #220 grit. Progress seemed to go … Continue reading →
In 1998, scientists studying telemetry from two historically significant robotic spacecraft (Pioneer 10 and Pioneer 11) noticed something odd: both craft were traveling more slowly than expected. They were experiencing a steady deceleration of about a billionth of a meter per second squared – vanishingly small from our regular earthbound perspective, but significant in the ultra-precise high-speed long-duration world of interplanetary navigation. Even when mission planners took such tiny factors as the gravitational attraction of the Sun and each planet, … Continue reading →
