When measuring the brightness of objects in the sky, astronomers use the magnitude scale. The basis of the scale we use today was invented by ancient Greek astronomers. They classified all the stars into six magnitudes. The brightest stars were magnitude 1, the next brightest magnitude 2 and so on. The faintest stars visible to… Continue reading The Magnitude Scale
Tag: Astronomy
Astronomy Items
Gliese 710: The Closest Future Star Encounter
Updated 21 November 2025 In 1.3 million years’ time the star Gliese 710 is forecast to pass within 0.166 light years of the Solar System, 25 times closer than Proxima Centauri which is our current nearest star (excluding the Sun of course). The close approach of Gliese 710 will be the strongest disrupting encounter known… Continue reading Gliese 710: The Closest Future Star Encounter
September 22 2024 – the equinox
In 2024 September 22 is the date of the September equinox and is also the first day of autumn (or the first day of spring if you're one of my readers in the Southern Hemisphere). In this post I’ll talk about the equinoxes and discus the commonly held, but not quite correct, view that they… Continue reading September 22 2024 – the equinox
Understanding Solar Day Length Variation
Revised and updated 12 February 2026 July 25, is one of the four days a year in which the length of the apparent solar day, the natural day measured by the rising and setting of the Sun, is 24 hours. I have written about this in previous posts but I thought it be worth mentioning… Continue reading Understanding Solar Day Length Variation
Starlink and other Large Satellite Constellations
Back in 2019, the year before the pandemic, many of you will have seen images of long ‘trains’ composed of up to sixty SpaceX Starlink satellites crossing the sky in a straight line. These pictures hit the headlines not only because of the number of satellites, but because of their brightness. A 'train' of… Continue reading Starlink and other Large Satellite Constellations
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