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!

MNASSA available online

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ASSA have recently launched the new web-page for their bimonthly publication, the inaccurately named Monthly Notes of the Astronomical Society of South Africa (MNASSA).  As part of the changes voted in at the last AGM, ASSA has stopped producing print copies of the Monthly Notes, and now publishes them as pdf files, to be stored on the MNASSA website.  As a bonus, this means that members will no longer lose their copies in the mail, and non-members will not need … Continue reading →

Juno images Earth and Moon

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On 26 August, three weeks after it was launched, the Juno spacecraft turned around and took a photo of home.  The maneuver was done to test the widefield camera, as part of a general testing procedure to check that all instruments are working properly.  At the time the photograph was taken, Juno was almost 10 million kilometers from home and traveling at a speed of 125 thousand kilometers per hour.    

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Spring Day

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 Here in South Africa, we will be celebrating Spring Day tomorrow.  The seasons are definitely changing – the black firebreaks are turning green as the grass grows in, the daily temperatures have climbed dramatically compared even to last week, and deciduous trees are sprouting new growth.  Soon the rainy season will begin (although if you live in Cape Town then all bets are off) and a new cycle of life and growth begins. But we are astronomers!  We are not … Continue reading →

The coldest stars in the universe

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WISE 1828+2650, the coldest brown dwarf known so far, is denoted by a green dot in very center of this infrared image. Credit: NASA/JPL When we think of a star, we usually imagine a nuclear-powered furnace of hot plasma, flowing and churning violently under the dual influences of convection and twisted magnetic field lines.  But many stars are so small and dim that they don’t burn at all – they are not massive enough to start nuclear fusion in their … Continue reading →