Binoculars are an ideal instrument for studying the night sky and
should be in every astronomers arsenal.
They have important advantages over telescopes - for example
they are cheaper, smaller, easier to use and more versatile.
Basically binoculars collect more light than your eyes, making dim objects brighter and giving some magnification. They can reveal planets and moons and give access to all kinds of deep space objects.

Binocular descriptions
Binoculars bear inscriptions such as '10x50' and '7x40'. The first number refers to the magnification (eg) 10 or 7 times. The second number gives the diameter of the larger objective lens in millimetres (eg) 50mm or 40mm, which relates to its light-gathering power.

Recommended sizes for astronomy are 7x50 or 10x50.

Focusing
First turn the central wheel until the binoculars give their sharpest image (this may be helped by shutting your right eye)
Then while keeping your left eye shut, gently turn the focusing ring on the right eyepiece until focus is perfect. Stars should appear as tiny pinpoints with both eyes open.

Defects
If binoculars show rainbow colours around a bright light source, the optics are poor quality. If images like stars appear double with both eyes but single with one eye, they are out of alignment. In either case, do not buy or take back to the seller.

Binocular shake
One problem of hand-held binoculars is that they magnify the natural muscular movement of your hands and make the stars dance around. To minimise shake, brace your arms or elbows on something solid like a wall or fence.

Binocular mounts
A mount converts binoculars into an astronomical instrument. A good camera shop will sell you an adaptor that fixes binoculars to a camera tripod. The tripod controls allow you to move and lock the binoculars in position. Star Centre will send you plans for an excellent DIY binocular mount which does not need a tripod and costs around £25 for materials.

Binoculars and the night sky
Star clusters, nebulae, galaxies, our Moon are ideal subjects for binoculars
They are an excellent gateway to the stars.

Projects With Binoculars

Are the 4 brightest moons of Jupiter visible?
Can you see the rings of Saturn?
Are you able to spot the planetary nebula M27?
Do the Pleiades look better through binoculars than a telescope? How many stars can you count!
If you cannot see the Andromeda galaxy try binoculars.