Sky of the beholder

The invention of binoculars brought the cosmos a little closer with convenience.

I WAS surprised to hear a friend say over lunch recently that he learnt something from me: always carry a camera and binoculars in the car, because you never know when something extraordinary might occur. The extraordinary thing for me is that I can't remember saying that to him, but by damn he's right, especially about binoculars.

Hans Lippershey was the first person to ask Dutch officials that he be granted a patent for the telescope - his request, in 1608, was unsuccessful and we'll never be sure who made the first telescope. But we're clear Lippershey made the first binoculars.

Binoculars in the crowd.
Binoculars in the crowd. 

Early examples were a little crude and they didn't flourish as did the telescope until Italian optician Ignazio Porro patented his image-erecting prisms in the mid-1800s. Nowadays they are almost ubiquitous, with a multitude of uses. For astronomy, though, they're the versatile sidearm that complements the heavy firepower of a telescope. They're quick to reach your eyes and give a very wide field of view when compared with a telescope. Binoculars in the 7 x 50 or 10 x 50 range give great sweeping views of the Milky Way, show the moons of Jupiter and craters on Earth's moon and can fit all the Southern Cross in one field.

It's essential buyers understand what the numbers mentioned above (and featured somewhere on the body of binoculars) mean. The first number tells how many times they magnify and the second is the diameter in millimetres of the lenses that gather the light. Because binoculars need to gather as much light as possible so faint celestial objects may be made brighter, I would not recommend anything smaller than 50 millimetres for astronomical use, even though this might make them a little heavier.

Second, because our pupils rarely open to their widest beyond middle age, for the under-45s I would recommend a 7x magnification and for others, I would suggest 10x magnification.

I could not recommend anybody spend more than about $120 to $150 for binoculars for astronomy purposes - unless you have money to burn, in which case buy the $5000 Fujinon binoculars and I'll come looking for a loan.

Unless you are an experienced astronomer, you will not notice much difference between adequate and superlative binoculars. And when you're done with the stars, you can take them to the footy, the races, the beach and even bird-watching. Do that with your telescope!

Follow Perry's tweets @Perryastronomy