What’s the difference between a Spyglass and a Telescope?

At first glance, a spyglass and a telescope might sound like similar artifacts, despite their names. As well as with different tools, both experienced and new astronomers have heard of them at least once, before embarking on their exploration journey across the cosmos. Because of both having similar functionality, people who are not familiar with their usage might see them as the same thing, often overlooking the details that make them unique. Now, the real question is: What is the difference between a spyglass and a telescope? This article will get to that in a bit.

A Telescope is an optical instrument designed to make distant objects appear nearer for your viewing. A Spyglass is a telescope but a much less powerful one and is used to navigate the oceans and seas of the world.

So what is a telescope?

All telescopes produce a scale image of objects that are too far for anyone to have a better glance. They tend to use lenses and curved mirrors, as well as a combination of all of the above to do so. Because of the way these artifacts are built, they are capable of emitting, absorbing, and reflecting electromagnetic radiation. Depending on the type, telescopes can use short wavelengths of both ultraviolet and visible light, something that applies to the x-ray and ultraviolet variants. However, their optical, infrared, submillimetre and radio counterparts are known to use visible light and microwave wavelengths, to name a few.

The longer the wavelengths are, the easier it is to use antenna technology that allows the user to interact with electromagnetic radiation. Therefore, near-infrared light can be collected without an issue, similar to its visible counterpart. However, those on the far-infrared and submillimetric side of the spectrum can only act as a radio telescope. Before all of these came into the picture, the first known models were refractor telescopes, which were used for astronomy, among other things. As science progressed, their variety expanded, and their magnification range rose to what it is today, which goes from 30x to 50x, providing a clear view of planets and constellations.

Different types of telescopes

Aside from the aforementioned types of telescopes, another way to classify them is by the location they’re being used at, such as the ground, space, and flying models. They have also been sorted by the person that operates them: professional and amateur. Of course, there are alternatives to the usage of telescopes with electric radiation, mainly in the form of detectors that can catch cosmic rays, neutral atoms from the solar wind, neutrinos and gravitational waves. These instruments deserve an article of their own, which is the main reason why they won’t be described… At least for now.

Ok, what’s a spyglass?

Spyglasses are a different beast. Unlike their more powerful counterparts, these are hand-held refracting telescopes that are heavily used for terrestrial observation. Thus, their magnification range will be lower. Of course, this doesn’t mean that the history behind them is less fascinating. They even have been used by pirates! But more on that later, since it’s crucial to get into how they came to be first.

Spyglasses were invented in the 16th century, and their magnification range only reached up to 3x, way lower than what it has today. It would have stayed this way if it wasn’t for Galileo Galilei, who increased it to 8x, only to max it up to 23x shortly after. These interesting fellows were responsible for many pirate attacks. Why? Because they used spyglasses to track those ships that would be the next victim of their heists.

Spyglasses used to be called collapsible monocular and either hand-held or portable telescopes. One curious thing about them is the fact that they used to be concealed as part of fans or scent bottles, as well as walking sticks! They used to be popular from the mid 18th century until the mid 19th century, ending up in museums once they faded into obscurity. During their prime, they used to be made of gold, silver, ivory, and even tortoiseshell, the latter being something that would be considered unethical towards the environment nowadays.

Why use a Spyglass

Even if there are telescope models that are more portable than their more stiff counterparts, these are no match for spyglasses, at least in this department. What they lack in magnification they compensate for ease of transport. These little critters are compact enough to carry anywhere because of their foldable design, allowing the user to adjust their length if needed. Thus, they can slide the eyepiece until they have the focus they’re looking for.