By Esteban J. Andrada
When we talk to the general public about astronomical instruments, we often hear the idea that a "big telescope" is synonymous with professionalism or advanced astronomy. This is a common notion in the popular imagination.
In theory, this statement seems to hold up: a bigger telescope is better because a larger aperture captures more light and provides better resolution. In practice, however, things can change. There are at least three key factors that can make a small telescope the best option for observation.
First, at the beginning of this article, there's a widespread myth: that you can't do serious observation with a small instrument. There are many amateur astronomers around the world who have contributed to tracking variable stars or comets with just binoculars, to cite one example.
Unfortunately, some people, far from the practical utility of observation, insist on buying large telescopes with the goal of showing off or impressing others. It's true that a large telescope can be impressive, but at the same time, it can be a disappointment, especially for a beginner. [1]
The title of this article contains a quote from the well-known American amateur astronomer Jack Newton, who said, "As you gain experience as an amateur, you'll come to understand that the best telescope is the one you use the most."
In my personal case, that phrase forced me to reconsider my own equipment, and it's a truth based on experience. The sheer size and weight of a piece of equipment can become a major obstacle. If setting up and taking down a 60-kilogram telescope in your yard or on your terrace is a tedious task, it's very likely to end up stored away after only a few uses. A smaller telescope is much easier to transport and use frequently, which increases your chances of enjoying the hobby.
Adapting to "Seeing"
"Seeing" doesn't refer to a clear sky, but rather to the stability of the atmosphere. The atmosphere has layers with different temperatures and densities that move, creating turbulence or interference in everything we see through it.
A large-aperture telescope captures more light, that's true, but it also captures more turbulence. On nights with bad "seeing," the image will be blurry and poorly defined, and planets won't show details on their surface. A small telescope, on the other hand, captures less light and also less turbulence. [2]
Thermal Acclimatization
Telescopes must be at the same temperature as the surrounding air. A large telescope has a large mass and takes much longer to cool down. If it's moved from a warm place to a cold night, the hot mirrors emit heat that creates turbulence inside the tube, distorting and blurring the image. A small telescope, with less mass, cools down quickly, allowing for a clear view almost immediately.
A Telescope for Every Lifestyle
If an observer only has time to observe a couple of times a month, investing in a giant telescope might not be the most sensible thing to do. The process of setting up and taking down heavy equipment can become tedious, consuming time and resources, and over time, this will have a causal effect: you'll lose the desire to use it and the satisfaction of astronomy will wane. In the end, that beautiful and powerful telescope could end up like so many others in the world, a bothersome decoration in the corner of the living room, gathering dust.
The reality is that, throughout one's life—and not just based on theory, but balancing theory with practice—most amateurs find more satisfaction in a smaller, good-quality instrument. Its ease of use and transport help us to take it out more often, ensuring that astronomy is an enjoyable hobby, rather than a heavy and un-fun one. [3]
NOTE
[1] The telescope doesn't determine the quality of an amateur astronomer. As the text mentions, there have even been great discoveries made with just binoculars!
[2] We should not forget other variables that harm observation, such as light pollution and air pollution.
[3] Some amateurs choose to build a home observatory. In that case, it would be wise to reflect on the potential use of the observatory, the free time you have available, and the maintenance budget for the dome or sliding roof. We should also weigh the geographical factor (city or rural area) against the quality of the sky at the site and the number of clear nights the site has per year.
