Buying your first telescope can feel like a big step, especially if you’re not sure what all those terms mean. So, to help you understand what to look for in a quality telescope, read below for all of the details.
We carry a small range (4-6 models) here at Coast Photo, it is always best to get in touch and we can let you know if the model you are keen on is in stock! And if not, – we can arrange this pretty quickly provided the suppliers have stock available. Feel free to reach out and we will give you a hand.
A telescopes aperture is the diameter of the main lens or mirror ( slightly less than the outer diameter of the main tube). Its purpose is to collect light and is the most important technical consideration. The greater the aperture, the more light collected, and this combined with the eye piece used determines the magnification and clarity of the object you are viewing. Light gathering power is proportional to the area of the lens or mirror, which depends on the square of the radius, so it increases rapidly with increased aperture. For example, a 200 mm telescope does not gather twice as much light as a 100 mm telescope — it gathers about four times as much.
Aperture is very important for visual observation (i.e. using your eye and an eyepiece) because it determines what you can see.
The telescopes magnification is important but not as important as aperture. A telescopes magnification can be changed by the eye piece used. Maximum useful magnification is approx. 2 times the aperture in mm, for example a 102 mm aperture telescope can usefully magnify up to 204 times. Trying to use an eye piece to magnify more than this will result in a narrow field of view and unclear image. Less magnification is often preferred as you get a wider field of view and increased clarity.
What will I see?
Astronomically, you can see the Moon, the Sun if correctly filtered, all of the planets except perhaps Pluto, some surface details on Mars, Jupiter and Saturn, multiple stars, globular and open clusters, bright nebulae, galaxies and nearby galaxy clusters.
The mounting system refers to the way the telescope tracks moving objects. An ‘Alt-Azimuth’ or ‘AZ Mount’ is the best choice for a general purpose telescope as moves the telescope in a simple left-right and up-down motion.
One of the most common types of telescopes, refractor telescopes are the versions typically featured in popular media. At the front of the telescope, a lens known as an “aperture” directs light through the scope to a mirror into the eyepiece. Because this style of telescope doesn’t invert the image before it reaches the eye, users can view objects both in the sky and on Earth. However, to view very faint objects in the sky, a reflector is best suited.
Reflector telescopes don’t use a lens; instead, their two mirrors gather and direct the light from the night sky. This process inverts the image, which makes viewing objects on Earth difficult. However, this method helps focus and provide additional clarity to objects that would appear faint in a refractor telescope. No lens means that dust and dirt may get into the internal components. Users should plan to clean the telescope regularly and store it in an appropriate location.