Author Archives: Allen Versfeld

About Allen Versfeld

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!

Globe at Night campaign

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Regular readers will be well aware of the growing problem of Light Pollution, and the increasing influence of groups working to restore our night skies.  An important part of any such efforts is understanding just how bad the problem is, and Globe at Night gives everybody a chance to help gather this information.  The current campaign started yesterday and runs through till 6 March. So what do you have to do to participate?  Not much!  First, find your exact location … Continue reading →

19 February – milestone in sight

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For the first time in this project, I went to a class with no progress from the previous session.  Thanks to a busy study schedule, I’d managed to do absolutely no work whatsoever on my mirror.  A side effect of the week’s inactivity was that I found the work more strenuous than usual – I haven’t had such back pain after an afternoon’s grinding since my very first day.  I either need to spend more time grinding glass, or get … Continue reading →

Man-made crater on Comet Tempel 1

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Images of comet Tempel 1, from Deep Impact (left) and Stardust-Next (right). Image credit: NASA/JPL-Caltech/Cornell; NASA/JPL-Caltech/UMD In July 2005, a NASA spacecraft called Deep Impact intercepted comet Tempel 1 and shot at it.  The 370 kg lump of copper that was fired at the comet hit at a speed of just over 10 kilometers per second – about 30 times the speed of sound on Earth.  The resulting explosion threw up a plume of debris which Deep Impact’s instruments were … Continue reading →

12 February – Milestone, sort of

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First of all, apologies for the late update.  On a whim, I decided to replace Windows 7 with FreeBSD Unix on my PC, and have spent the last few days getting all my software installed, and the environment tweaked exactly the way I like it.  It’s looking good.  I have to say, I’m impressed – the KDE window manager has moved a very long way since I last used FreeBSD as a desktop operating system 7 years ago. Saturday I … Continue reading →

Glory to launch 23 February

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NASA’s Glory mission, previously described on Urban Astronomer (NASA’s Glory) is scheduled to launch Wednesday, Feb. 23, from Space Launch Complex 576-E at Vandenberg Air Force Base in California.  Data from the Glory mission will allow scientists to better understand how the sun and tiny atmospheric particles called aerosols affect Earth’s climate. Both aerosols and solar energy influence the planet’s energy budget – the amount of energy entering and exiting Earth’s atmosphere. An accurate measurement of these impacts is important to anticipate … Continue reading →