Never before have stargazers been faced with so many different choices of astronomical telescopes and associated accessories. This can make it more of a challenge, especially if you are just starting out as an astronomer.
First of all, it’s worth understanding some basic principles. One of the most important aspects of all telescopes is aperture, or the diameter of the main optical component, which may be a mirror or a lens. Essentially, the bigger the tube, the greater the aperture.
Aperture determines a telescope’s light-gathering capacity and its capacity for seeing fine detail in an image – this is also called resolving power.
As an example, with a six-inch telescope you can see lunar craters as small as just a mile wide, and, overall, a 6-inch telescope has four times the light-collecting area of a 3-inch version.
However, the aperture is not related to a telescope’s magnification or power. Instead this is determined by the distance between the lens or mirror and the point where it creates an image of a distant object.
Another important thing to understand is that larger apertures are more affected than smaller ones by “poor seeing” – or poor atmospheric conditions affecting visibility.
Other factors in your decision include portability of your telescope, budget, and whether you want to spend your time looking at the moon and the nearer planets or “deep sky” objects like dim galaxies, nebulae and star clusters.
Size is also a factor in that clearly a large telescope will need to be housed permanently in an observatory or assembled for each new viewing session. So bigger isn’t necessarily always better.
Finally, bear in mind that all telescopes are also divided further into three other classes:
Refractors can be expensive but can also provide some of the finest images available for each aperture when made properly. They are also very robust, with their lenses less likely to come out of alignment. So they could be ideal if you’re not one for playing around with the optics.
Reflectors or mirror telescopes uses mirrors to gather and focus light from the object being observed. The most commonly found version, the Newtonian, has been around for more than three hundred years. Want maximum aperture for your money? The reflector could well be the scope for you. Bear in mind however that the Newtonian in particular does require occasional maintenance.
Finally, the catadioptric or compound telescope uses lenses and mirrors to form an image, so that for many they offer the best of both worlds, with a large aperture and a long-focus, transportable telescope.
Optical Equipment from Sherwoods Photographic
At Sherwoods we specialise in all kinds of optical gear, whether you need night vision equipment or anything else. We’re a third-generation family owned firm first established in 1942 and offer extensive knowledge and expertise in our chosen field.
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