Binocular Astronomy

“Two small telescopes” joined by a hinge, giving a low magnification view. The hinge allows the binoculars to be adjusted between the observer’s eye and the objects. There are many sizes and types of optical binoculars, some of which are suitable for deep sky observing and some that are most definitely not! Binoculars have design such as 10×50, where 10 times is the magnification and 50 is the diameter of the lens in millimetres.

Choosing Binoculars
High magnification (power) binoculars are not needed for astronomy ~ those with a magnification of more than 10, magnify the user’s movement to such a degree that can make viewing more difficult to recognize the objects in the constellations.  One of the best pieces of equipment to start with is a pair of binoculars that can be used to view brighter Messier objects. Opera glasses are not suitable for astronomy and neither are the small pocket binoculars of 25mm aperture. The best ones for Observing are 7×50, 8×40, or 10×50 perfectly acceptable ~ Any larger than this and they will need to be rigidly mounted on a tripod or they will shake so much you will see nothing except dancing stars! The larger the lenses, the brighter the image, but this will make the binoculars very heavy.

Mounting Binoculars
Many binoculars have a standard camera tripod screw thread set into the body, which makes attachment to a camera tripod simple. There are other small appliances and means of supporting them but this may involve buying or making something extra.

Buying Binoculars
If you were buying for the first time a pair of general binoculars with astronomy in mind, my advice would be not to go for too large a pair and not recommend to buy any zoom lens binocular, that, that  is not ideal for celestial (Night Sky) viewing.

Testing Binoculars
It is possible to test binoculars during the day by viewing a distant object, such as a tall building, outline seen against a bright sky. Adjust the binoculars, and then look at the edges in the field of view for distortions may affect the field of view and make the stars near the edge appear blurred ~ check that an object remains sharp from one side of the field of view to the other without the need to refocusing during the daylight and false colour. Show up as red and blue or green and pink edges of objects seen against a bright sky ~ Bad false colour which may appear not too serious in the day but will be very obvious when observing the moon at night.

The advice to beginner astronomer is often to get before thinking about buying a telescope, though some people argue that you won’t be happy until you got a the telescope anyway. Many of the cheaper binoculars from Departmental Stores are useless. For the amount of money you would pay for a poor quality small telescope, you can purchase a well-made pair of binoculars with a quality optics that last a lifetime! Observing with a naked-eye, even though magnified just a few times (7×50 ~ 10×50), they bring into view many thousands of stars and other objects that are invisible with the naked-eye alone!

Never look at or near the Sun through binoculars.
Permanent blindness will result even quickly look at the Sun.


Back to `Your First Night Sky` page.

Comments are closed.