Planets gathering in predawn sky
Today will be momentous for the Griffin clan. Come rain or shine, my oldest daughter Hope is getting married this afternoon at a topsecret venue on the Otago peninsula. Of course, as a proud father and as an astronomer, I’m very much hoping the sky gods come down on the side of shine after a relatively long run of cloudy skies in this part of the world.
If the sky remains clear overnight, there’s a lovely gathering of planets in the morning sky, which is well worth getting up early to enjoy (even if you have a postwedding hangover).
In my last column before Christmas, I mentioned that Venus is currently putting on a pretty good show. The second planet from the sun rises just after 3.30am and, by 5am, will be a blazingly bright object some 13 degrees above the horizon. Venus is moving through the constellation Ophiuchus, the serpent holder, and at dawn tomorrow, it will be just over
188 million km from Earth.
If you find a viewing location with an unobscured horizon, you should be able to find two other planets. Mercury reached its greatest western elongation from the sun several days ago. It will be relatively easy to find below and to the right of Venus. The innermost planet is moving through the constellation Sagittarius. It rises just before 4.30am and, by 5am, will be nearly six degrees above the horizon. Despite being 30m km closer to us, Mercury is much dimmer than Venus. However, the planet’s distinct pinky/white colour should make it noticeable even as dawn brightens the eastern sky.
Mars is the final planet in this week’s predawn gathering. It will be more challenging to locate than its celestial siblings because it is dimmer and considerably lower in the sky.
The red planet rises at 4.45am and has an altitude of just under three degrees at 5am. You will probably need a pair of binoculars to find it, especially as the sky gets brighter.
Like Mercury, Mars is in the constellation Sagittarius.