 Greetings and welcome to the Introduction to Astronomy. In this week's Misconception in Astronomy, we are going to look at the idea of magnification of a telescope and understand why it is not the most important property when we are looking at telescopes. So, let's get started. I mean, what you know is that telescopes are what we use to view astronomical objects. And a telescope is considered to have three powers. It has light gathering power, how much light it is able to detect, it has resolving power, how much it is able to resolve the detail you are able to see, and it has magnifying power, how much it is able to magnify things. To an astronomer, it is the first two that are the most important because they allow us to see fainter objects, the more light we get, the fainter objects we can see, and they allow us to see more detail. So, for example, if you get an image of the planet Saturn, and you can see one here that's a little on the blurry side. Now, that's still a decent image of Saturn. In many cases, looking through a small telescope from Earth, you're not going to see a lot of detail on Saturn, as you will with the beautiful images we get from space. So, you can magnify it, but magnification does not change these other two powers. The magnification power also can be relatively easily changed. While the first two powers depend on the size of the lens or the mirror that makes up the primary objective of the telescope, the magnification depends on the focal length of the primary mirror and of the eyepiece. The eyepiece can be easily changed but the magnification would be relatively easy to change. Now, that can be changed, but it does not improve things. So, if you take an image like this and enlarge it, you're only going to get a bigger blurry image. You're not going to see anything else. It's not going to give you any better resolution. It is not going to give you any better light-gathering power. Now, how does the light-gathering power work with this? Well, if you imagine getting a small image, and let's take an image, a little sketch of Saturn here, and if we can imagine that this is Saturn and we see a little object here with the rings and it's relatively bright. We can kind of see what's happening there. We can see that there is a little bit of a body here and then two rings coming out on either side. Now, this has, just for the illustration images, there are eleven dots in the image. So, it takes about eleven dots make up this image and when it's small, you can see the object. Now, you don't gather any more light by magnifying. So, if we magnify this image and take those same number of dots but increase the, make them bigger, now we're going to get a much fainter image and it's going to be a lot harder to see. You can magnify an image and honestly make it invisible simply because there is not enough light being gathered to justify such a large image. So, here we see the same number, those same eleven dots in the same kind of pattern and yes, Saturn is there but it is nowhere near as well defined. There's the object but look at how few dots there are there and then we see the rings. So, not near as well defined when you do a high magnification when the light gathering power is there. So, if you're looking for a telescope you want to try to get the biggest telescope that you can reasonably afford and that will work for what your purposes are. So, it really depends on what you intend to do with the telescope. So, you want to be able to gather as much light as you can to see fainter objects and resolve to see fine detail. So, let's go ahead and finish up with our summary. We talked about the three powers that a telescope has. We said the most important two are the light gathering power and the resolving power and that the magnifying power here is the least important of these to an astronomer. So, that concludes this misconception on magnification being the most important property of a telescope. We'll be back again next time for another misconception in astronomy. So, until then, have a great day everyone and I will see you in class.