Knowing how to buy your first telescope can be a tricky business. Follow these useful tips, though, and you should be well on your way to getting the perfect instrument for some enjoyable astronomy sessions.
Buy an instrument from one of the major manufacturers. Not the sort that might be found in a department store or mail-order catalogue – these instruments invariably disappoint.
The choice of the correct telescope is then very important if it is to be used regularly. One which is too big, too small or the ‘wrong’ type may be shelved prematurely – consider how the telescope will be used. How portable does it need to be? Will it stay at home or be taken places? Will there be any daytime use (such as birdwatching)? Is any astrophotography likely to be attempted?
One critical aspect of any telescope is its aperture. This is the diameter of the optical system, usually measured in millimetres. The larger this number, the more light the telescope gathers, providing brighter images, showing fainter objects, more vivid colours, allowing higher magnifications (when practical) and showing more detail.
The focal length of the optical system too is important as this determines image scale and determining the optimum range of magnifications for a given telescope and often making it more or less suitable for a particular type of astronomy. General purpose telescopes do exist, but there’s always a compromise to be made.
Answered by Simon Bennett from The Widescreen Centre