There’s nothing quite like gazing up at a celestial body and realising how much detail you can see even from hundreds of thousands or even millions of kilometres away.
The Moon makes a good visual target for beginners, and it’s actually only 384,400 km (240,000 miles) from Earth.
First, it will help if you understand a little about how telescopes work. The telescope’s primary function is not to magnify the appearance of the Moon, although it will do that. It works by collecting light and directing it to your telescope’s eyepiece so that you can see it clearly. It bends the light to fit the size of your eye’s pupil.
With a refracting telescope, which was invented in 1608, the lens at the far end of the instrument collects light and bends it into focus. Johann Lippershey invented this device, but Galileo was the first one to point it at the sky. It directs the light to a place in the telescope called the focus, where the light is bent into a pin-sized image.
The light then leaves that pinpoint and the ray of light expands as it gets closer to your eye until it is the same diameter as your pupil.
The reflecting telescope is just a bit newer—it was invented by Sir Isaac Newton in 1680 specifically to eliminate the colours of the rainbow that interfered with best vision of an object. It utilises a concave mirror—that’s a mirror that has a sunken-in appearance—to collect the light.
This mirror placed in the back of the tube redirects the light outward to the eyepiece. As with the refracting telescope, the ray of light hitting your eye should be no larger than the diameter of your pupil.
Reflective telescopes are commonly referred to as Newtonian and add a swivel base that make sit a Dobsonian telescope.
Which One Should You Buy?
If you have a general interest in watching the Moon—or whatever you see in the sky, and maybe a few Earth-bound subjects as well—then a refracting telescope will be the better and less expensive choice for you. A 70mm refracting telescope is a good starter instrument. If you seriously intend to study astronomical bodies, then invest in a reflecting telescope; you will get more lens for your buck.
However that being said, if you want to view the night sky only, a Dobsonian telescope is the way to go.
The Dobsonian is way easier to use also. One big thing to remember is the bigger the mirror, the more light it collects and the more stuff you’ll see in the night sky.
Telescopes do not work well if you want to visualise moving objects such as the International Space Station or orbiting satellites. Even though you think you can track an object that’s visible to your naked eye with your telescope, you will see it better with binoculars, which allow you to move your head and your binoculars as one unit.
You will also want to consider other features. What fits into your budget? Do you want something that’s more portable? See the list of accessories below.
You might want a model with a finder, which works the same as the sights on a rifle. There are peep sights, with notches, or reflex sights, which illuminates your target and even sends a pinpoint of red light out to it, much like a laser light. A telescope sight has crosshairs, just like a rifle sight.
The telescope also eliminates colours that will be distracting from the image you’re visualising through the use of various filters. They are beneficial if you are looking at the Moon through a haze of pollution or to create contrast so that you can see the details more clearly.
A dew cap will shield your telescope from condensation typical in the cool night air.
You can even buy special camera attachments that you can use on the telescope so that you can photograph what you see. And yes, you can take pictures of the moon using your iphone!
Tips For Viewing
Obtain a reliable map of the sky. Besides the Moon, you’ll want to know what else you can see from where you live.
You can also visit the NASA.gov (spotthestation.nasa.gov) website for a list of dates and times when you can view the International Space Station.
Look at the Moon carefully with your naked eye before you view it with the telescope. Examine what you can see of its valleys and craters. Only when you’re completely familiar with it should you put your eye to the telescope.
Don’t make the mistake of viewing the Moon when it’s full. The light from the Sun that’s illuminating it will detract from what you can see. The best time is when the Moon is at one-quarter or three-quarters.
The Moon really isn’t that bright, but it may appear so because you’re accustomed to seeing a small Moon in a dark sky. If the Moon seems too bright when you’re viewing it, place a couple lamps in your viewing area.
Or wear some sunglasses – Or even better, get yourself a Moon Filter for your eyepiece.
Enjoy your next moon watching adventure,