Tracking the Tropic

photo Beth Jackson

photo Beth Jackson

Artist Michael Pospishil relates his search for the Tropic of Capricorn whilst on the Bimblebox Nature Refuge

Astronomy is one of my interests and I noticed that Bimblebox was somewhere near the Tropic of Capricorn when I looked it up on a map beforehand. I was guessing that it was somewhere near the northern boundary.

The Tropic of Capricorn is the southern tropic, the Tropic of Cancer being the northern. They mark the extremes of the apparent movement north and south of the sun, and so mark the limit of the tropics. Due to the wobble of the earth’s orbit (precession of the poles), their position varies over time. At present the Tropic of Capricorn is moving north at the rate of about fifteen metres per year. Its latitude in 2013 was 23° 26′ 14.440″ south of the equator.

Mick carving the marker, photo Beth Jackson

Mick carving the marker, photo Beth Jackson

I set out to find it. With the help of Paola’s computer and wikipedia (yes, I admit I am a wiki-phile) I found it’s latitude and with the help of Greg’s GPS and accompanied by Beth and (paradoxically) Zena, set off in my trusty Mirage along the road south to the dongas. Zena womanned the GPS.

photo Beth Jackson

looking for the Tropic of Capricorn, photo Beth Jackson

photo Beth Jackson

Somewhere near here…, photo Beth Jackson

We eventually found the approximate spot about 500m north of the dongas and (with a peg I had prepared earlier with the latitude chiselled into it’s face and ‘L’ on the back to confuse future historians looking for the remains of Ludwig Leichardt) got out to narrow it down. After wandering back and forth a few times, we managed to locate it to within about six metres, fortuitously where a forked ironbark stood. I whanged the marker peg into the ground at the base of the tree, where it would be safe from itchy cattle. We ceremoniously and solemnly saluted it for posterity. It ran smack through the middle of Bimblebox.

photo Beth Jackson

Ah, there it is, photo Beth Jackson

photo Beth Jackson

photo Beth Jackson

photo Beth Jackson

photo Beth Jackson

salute to the tropic of Capricorn, photo courtesy of the artist

Salute to the tropic of Capricorn, photo courtesy of the artist
Mick standing on the Tropic of Capricorn, photo courtesy of the artist

Mick standing on the Tropic of Capricorn, photo courtesy of the artist

I later calculated when the Tropic would be at the artist’s camp and carved ‘2208’ into a nearby dead tree, in the faint optimism that the tree would still be standing then, rather than trashed for the underlying darkness.

photo by Beth Jackson

The Tropic of Capricorn will be here in 2208 photo by Beth Jackson

photo Beth Jackson

photo Beth Jackson

Paola and Ian are fortunate that they live in the nice cool temperate zone, but only have to travel 550m north to enjoy a warm tropical holiday. I hope they don something gay when they do.

The summer solstice in the south (the day that the sun is furthest south) is on the 21st of December, and I contacted Ian to let him know that if he stood next to the peg at local noon on that date, the sun would be directly over his head and he would be standing on his shadow.

The mine was approved on the 20th of December. Spooky.

photo Beth Jackson

photo Beth Jackson

One response to “Tracking the Tropic

  1. How wonderful that the Tropic of Capricorn will be immortalised on Bimblebox. Maybe the Tropic of Capricorn will take out any bulldozers that try to destroy this sanctuary. I can’t wait to see the marker when next I visit Bimblebox. Thank you everyone.

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