How to Choose a Telescope

Saxon 705AZ3If you are looking at purchasing your first telescope or just researching what is available in the market, here are some simple considerations and rules to help you along the way.

Optical equipment and terminology can quickly become a very complicated subject so we have tried to strip away the jargon and give you a framework to make sure you get the right first telescope.

If you want more technical detail you can check out Frequently Asked Questions - Telescopes
Decide what you want from your telescope Since there are many models and kinds of telescopes, the best thing is to ask yourself what you need your telescopes for. Are you going to use it just for astronomy, land/sea viewing, bird watching, looking at the view from you deck or some sort of combination? Are you a beginner and want to learn on a smaller model or buy a larger one to grow in to over time? Is it going to be in one place or do you want to transport it around? How much room have you got to store it? Will it fit with the style of the house you have? These are some of the questions you may need to consider.
What is your budget? Telescopes are expensive. Identifying your budget helps in choosing just the right ones for you. However, like any other products, the higher the price is the better quality the product has. For example, you can't compare the quality of the results of a fifty-dollar camera to a ten thousand dollar camera. The same thing applies with telescopes.
As a rough guide, be prepared to spend about $250 for a reasonable quality though small telescope; if you are not prepared to spend this amount you can also consider checking out binoculars where there are cheaper options. As your budget increases so does the size and quality, good quality/medium size telescopes for $500-$1,500 and good quality/large telescopes $1,500+.
Size counts  The larger the objective lens or mirror (the big light collecting part of the telescope), the more you can clearly magnify the image when you are viewing but it comes at a cost; the larger the aperture, the telescope becomes heavier (harder to move), takes up more space and becomes more expensive. First telescopes are normally 60mm-130mm aperture size with the most common being in the 70mm-90mm range.

Magnification counts (but not as much as size). Don't choose a telescope just by its advertised magnification. The way to compare similar telescope is by aperture; that is, the size of the objective lens or mirror. As a rule of thumb, few scopes can deliver more than 50x per inch of aperture under the best conditions; That means that the 2.5" (60mm) telescope advertised as a "625x telescope!" is really a 125x scope at best!

Buy quality : There are plenty of cheap telescopes out there, inferior lens/mirrors, mounts and general construction that will only disappoint when you use it and probably wind up stuffed in a cupboard. A good quality telescope will be used for many years and give enjoyment each time.

Look for a decent warranty period, reputable brand, ideally with a New Zealand agent. We stock only brands where the manufacturers stand behind their products; Saxon, Celstron, Leica and Steiner who all provide support, advice, repairs and warranty.

Although size is very important, the quality of the optics is critical, a small scope with excellent optics can see more than a large scope with mediocre optics. If you want more technical information, you can look at the individual telescope product details.

For astronomers, there's no substitute for darkness. Basically you have to choose between a huge scope that sits in your light polluted city back yard, and a small scope that you can carry out to remote, dark areas, go small and transportable. Light pollution is the major factor in your viewing experience, if you can reduce it by moving you will have a far more enjoyable time.

The smaller the scope, the more often it gets used. This is a simple point that is often overlooked. Whether for land viewing or astronomy, if you can pick up your small telescope, and move it easily outside you will use it more often than if you need to prepare and move a large telescope. A 70mm telescope usually weighs less than 10 kg, is not too bulky and can easily be moved by one person, a 203mm telescope will need two and can only be moved with some difficulty so it will not get used as much.

The mount is as important as the scope. Without a solid, steady mounting (usually a tripod), you can't even focus properly, let alone view or do things like photography.  Most good telescopes have metal mounts which will support the telescope providing a solid base for viewing.

There are two major types of mount, Alt-azimuth or AZ (mount allows the telescope tube to be moved up/down and left/right) which is used mainly for land viewing and Equatorial or EQ (designed to follow the path of planetary bodies as the Earth turns) used mainly for astronomy. Easy way to tell is to look at the telescope reference, the mount type is usually at the end e.g. 909AZ3 or 909EQ2. 

After considering these points you are in a better position to make an informed choice about your telescopes purchase. There are three major types of telescope that you can look at.

1.Reflector – this type uses mirrors to transmit light, if you want an astronomy telescope only these are the best value for money, they are a simple construction that gives you the largest  light collection for you dollar. Comes with an EQ mount for astronomy. Starts at about $400 for a 114mm unit.


2. Refractor – this type uses lenses to transmit light, great optics, can be used for both astronomy and land viewing, smaller units come with an AZ mount and larger with EQ mount, look like traditional telescope, starts at about $250 for 60mm unit. If you want a land viewing telescope 60, 70 and 90mm units with an AZ mount are good, if your interest is more towards astronomy look at the larger units with an EQ mount


3.Maksutov Cassegrain (Catadioptric) – this type uses a mirror/lens combination to transmit light, expensive to produce as they use both mirrors and lenses but very compact, easy to transport and a popular choice Smaller units have AZ and EQ mounts. A 90mm unit will cost about $750.

You can also consider spotting scopes as a lower powered alternative to telescopes that are compact, portable and robust.

We hope this has helped you a little. If you need further help you can contact us at staff@telescope.net.nz
or phone 09 422 2071