Norman Izett is president of the Whakatane Astronomical Society.
The society runs the Whakatane Observatory at 17 Hurinui Avenue.
For more information about events at the observatory visit the Whakatane Astronomical Society Facebook page.
OVER the past month there has been quite a change in the sky.
Firstly, in the west just after sunset the glorious conjunction of the planets Mercury, Venus and Jupiter appeared very close together. We had some great views prior to their closest meeting, on August 27, but on the very night, total clouds.
The next time for this to occur will be 2065. Since then Venus is the only one left as it rises higher each night, having passed the bright star Spica by now. Mercury hastily dived out of view between us and the sun, while Earth has sped on in its orbit, leaving Jupiter out of view behind the glare of the Sun.
Venus is the third brightest celestial object after the Sun and the Moon. Because of this brightness, it appears to vary to all colours of the spectrum, particularly as it nears the horizon. This is purely the effect of turbulence and moisture in our atmosphere in the same way our vision of what we see is affected by the mirage off a hot summer road or sandy beach.
This is the reason all the big professional observatories are sited on very high mountains with a dry-as-possible climate.
For those of you who are filing these articles, as of writing this chapter the current position of the planets to see the change is; Mercury, 0.771 astronomical units * ; Venus, 1.425; Mars, 1.014; Jupiter, 6.455; and Saturn at 10.309.
Overhead, Scorpio, and all the other constellations, continue to progress westward and Mars, because of its relative closeness, has moved into Sagittarius.
The relative positions of Mars, Saturn and the giant star Antares has changed quite a lot. Saturn, to a lesser degree, being so much further away.
So only three planets are now visible in the evening sky. To the south, the Southern Cross continues on its circular path and is now below the horizontal with the two pointers near-vertical, while opposite the Cross, easy-to-find star Achernar circles higher. Also to the south east, the giant star Canopus is appearing again after it’s short journey below our southern horizon.
* AU (Astronomical Unit) is the average distance from Earth to Sun = just under 150,000,000 kilometres.
Norman Izett
-Contributed