Buy telescope: the parameters for choosing a telescope

We briefly explain the main parameters that you should know to choose a telescope.

Telescopes have 3 very important parameters:

• The aperture designates the diameter of the objective lens or mirror.
• Focal length is the distance between the objective lens or mirror and the focal point.
• Stability (tripod and mount)

Then come the extras, for example: automated systems to guide the telescope from your computer, tablet or smartphone.

The aperture is the most important parameter, the larger the aperture, the more light the telescope will capture and the higher its resolution. The latter means that the telescope is capable of showing smaller details.

However, it also happens that the larger the aperture, the more sensitive the telescope is to terrestrial air turbulence. Therefore, large telescopes can only demonstrate their performance under good observing conditions.

Aperture is measured in millimeters and, since many telescope manufacturers are American, it is often also stated in inches, with 1 inch equaling 25.4 mm.

So, for example, a telescope with a 200 to 205 mm aperture is designated as 8".

Therefore, if the aperture is 150 mm, it is much better than a 70 mm telescope if we want to see smaller objects, for example, the moons of Mars, Jupiter and Saturn.

Compared to aperture, focal length is actually not a relevant telescope parameter. The longer the focal length, the less you have to magnify the image with the eyepiece. Therefore, long focal length telescopes allow higher magnifications to be achieved. However, this means that the field of view is smaller.

The mount is a fundamental component of telescopes. It doesn't matter what type they are.

We can now use the best telescope in the world with the best optical quality, and if we do not work on a good mount the observation will not be pleasant at all. When choosing a mount you must pay attention to its stability and, if you are not sure, it is better to consult us first.

On our website you can open the telescopes for beginners section and filter by aperture:

You can sort by price and if you have questions about a telescope you can send us a WhatsApp to +34 606 56 62 98