When it comes to choosing the right astronomical telescope, you should first consider your requirements. You must find out the reason why you want to have a telescope. In other words, you must know your needs of having such device. Hence, it is recommended that you must go through deeply all the visible as well as hidden aspects of this device. Here, in this article, we'll try to explain some tips and ideas on how to choose right one for your needs.
There are mainly two parameters that should be kept in view while looking for a device i.e. aperture and focal length. Here, aperture means the diameter of mirror or lens, and focal length means the distance from a particular objective mirror or lens to point or where a particular image is created. Thus, with some simple calculation, you will be able to find out right one for your requirements.
What is Telescope Aperture?
A telescope aperture can be described as a physical or visible size of a particular telescope. It means that the bigger the aperture is the more light collecting ability a particular telescope has. Take for instance, a suggested aperture for a first telescope need to be minimum 100mm especially for refracting device, or about 150mm for a reflecting device or telescope. If you analyze these figures, you will know the importance of the aperture.
It is a scientific truth that the pupil of our eye can reach about 8mm in diameter especially when completely adapted to a dark location. So, it's simply equivalent to an area of around 50 square mm. This is the main reason that a refracting telescope normally has an aperture of about 100mm in diameter, and thus covers an area of about 7850mm2. It means that a telescope with 100 mm aperture is simply capable of capturing 7850/50 = 157 x light. It is then available via the eyepiece of a particular telescope. Therefore, it means that if you look through a particular telescope, it will let you to discover objects about 157 times larger than actual size.
If you follow the same calculation, you will notice that a 150mm aperture telescope can help you to see objects that are 353 times larger than would be seen with your unaided eye. In all, if you want to avail the maximum benefit of a particular astronomical telescope, you need to select maximum size of aperture. This will certainly help you accomplishing a desired task.
What is Magnification and Focal length?
Now, have a look at what are magnification and focal length? A focal length represents the physical length of a particular telescope or it may represent its optical arrangement. It means that a small-sized focal length can provide you a view of wide field such as vision of night sky. On the other hand a long focal length can offer you a very narrow field of vision or view, but with the objects displaying relatively larger than original size.
Now, come to magnification of a particular telescope. It is actually a combination of telescope, telescope eyepiece and focal length. Needless to say that a telescope of a particular focal length can offer a picture of a particular size that could be fixed and won't be vary. Moreover, the eyepiece is used just like a microscope to view desired images. It means that if you change the eyepiece, the magnification of a particular astronomical telescope will also be changed.