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!
It is official – my mirror is done grinding. Although I had planned to stop at #800 grit, I found myself with time to kill at the last class, and decided to give it a few wipes with #1000. I spent about 45 minutes working with this stuff, so that I’m confident my mirror is now a perfect spherical section, within a tolerance of about 8 microns (since that’s about the average size of individual grains of #1000 carborundum). Which … Continue reading →
Artist’s conception of WISE. Credit: JPL One of my favourite space observatories was the Wide-field Infra-red Survey Explorer (WISE), both for the scale of its mission and the shortness of its planned life. Built to survey the entire visible universe in infrared, it took ten months to image every single part of the sky in detail using its exquisitely sensitive infra-red cameras. Two operate properly, the most sensitive cameras had to operate at temperatures close to absolute zero, and were … Continue reading →
Jupiter has a mass of about 1.9 x 1027kg – 1900 trillion Trillion kilogrammes. That’s more than double all the other planets, asteroids, comets and dust of the entire Solar System put together. Jupiter is BIG, yet still manages to not weigh anything at all. How? Because it is in orbit around the Sun, just like an astronaut orbits the Earth, and so experiences zero gravity. That’s not to say there is no gravity around Jupiter – it has plenty gravity … Continue reading →
Today was not a good day for me. In my day job, I work as a systems administrator for a team of software developers, and my Monday started off with some massive system failures. The team have a shipping deadline in less than a week, and there is still a significant amount of testing to complete. The pressure was on, and I only left my office at 6:30 pm. So why am I in such a good mood? Two reasons: … Continue reading →
This eleventh week of 2012 sees Tapani Isomäki of Links Through Space presenting the 240th Carnival of Space. Links Through Space is the official web presence of the Toutatis astronomy clubin Finland, and the Carnival is a way to present the best and most interesting writing of the past week.
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