How to look through a telescope: The Art of Viewing the Heavens

It seems simple, but many beginners get frustrated with their first views through a telescope because nobody ever showed them how to view the sky or what to look for, or more importantly how to look through a telescope.
It might surprise you that it isn’t as simple as peering into the eyepiece and turning the focus knob. In this guide we’ll teach you how to get the most out of your viewing session by concentrating on the following skills.
- Learn the Sky
- Focusing the Scope
- Dark Adaptation
- Choosing an Eyepiece
- Use Averted Vision
- Mind the Sky Conditions
- Get More Viewing Time
Learn the Sky
The very best thing you can do in astronomy is to learn the layout of the stars in the night sky, particularly in your area, specifically your latitude.
There are several astronomy books available to help you find the brightest stars and learn how to find them by learning their constellations and asterisms. These are groups of stars that take on a certain shape and can be recognized easily.
Or surf the net and compare what you see to the night sky. Orion, Cassiopeia, The big and little dippers, Sagittarius, Pegasus, and Draco will get you started. You should also learn to find the brightest stars as well, such as Vega, Arcturus, Sirius, and Deneb are good ones to know, as is the not so bright Polaris.
There is so much to study, you don’t want to overwhelm yourself. A good night with a star chart and nothing but your eyes, or perhaps a binocular, should really be your first astronomy class. Don’t forget a blanket, as it gets cold at night sometimes.
Focus the Scope
The moon is a pretty easy target. All you have to do is point the scope and turn the focus knob until it looks clear.
This isn’t so with deep sky objects, also known as faint fuzzies. The best way to focus your scope is by turning on either a bright star or a planet first, and make careful adjustments until you see nice pinpricks.
Once you do this, the focus is set, and you shouldn’t need to touch it again until you swap eyepieces.
This is because most objects in the night sky are far enough away that they are effectively infinity, at least compared to the size of your telescope. Once you find that sweet spot, most things will be perfectly in view.
There will be some tinkering with planets and the moon, because these are close, but everything else from binary stars to distant pulsars to outer planets like Neptune will focus at the same adjustment. Set it on an easy target and forget it.
Dark Adaptation
It sounds like a good name for a horror flick, but dark adaptation is something every astronomer is accustomed to.
Newcomers think that this means pupil dilation, which happens within a matter of minutes and dramatically increases your ability to see in the dark, but there is more to the story.
Your eye has little cones and rods that act like the pixels in your eye camera. Cones collect color information while rods are black-and-white, but very sensitive.
When you are in a dark environment long enough, say a half-hour, a chemical change takes place in your eyes where the cones are turned off and the rods are turned on. This gives you the sensitivity needed to find really faint objects.
There is a catch, however. One flash of light from a phone screen or flashlight, and the process has to start all over again. The exception is red light, which doesn’t bother the rods as much, but it should still be really dim.
Lay under a dark sky for a half hour and you will literally see the difference as your eye goes through the change. First only bright stars will be visible, then dim stars, and then the hidden dust behind it all will begin to appear. It gets better the longer you can stay away from ambient light.
Choosing an Eyepiece
More magnification is not the answer.
There are many people out there who buy “quality” stuff and then complain that they can’t see anything. Putting the highest magnification eyepiece first is typically the problem.
When looking for DSO’s (deep-sky objects), comets, and other astrological phenomena, I find myself scanning with my eyes first, binoculars second, and then panning with a wide-view eyepiece like my Orion 38mm Q70. The gradual reduction in magnification keeps the object bright while I zero in on it for whatever details can be teased out.
I spotted a comet one night with the naked eye, and then parked my travel scope on it to get a nice view.
Bigger isn’t always better. In fact, some items like the Andromeda Galaxy, most comets, and larger nebulae will be too big to take in at 200x, and spread out so much that you see nothing.
Always start at low magnification, which is the highest focal length eyepiece you have, or a binocular.
Planets will let you zoom in as the sky and your scope permit. Don’t go more than twice the main optic diameter in magnification and you’ll be okay. An 80mm scope won’t show much past 160x, not over 400x on a 200mm(8-inch), etc. When the atmosphere starts making things wavy, back of the magnifier.
Star clusters are also good for pushing the magnification limit, as are double stars.
Galaxies and planetary nebulae will take some magnification quite well, but it’s still best not to get carried away. About half the primary optic is usually good. As you hop up from one eyepiece to another, take note if things start to look dim or more blurry. This is the point of no return, and it’s good to back up one eyepiece.
For really dim stuff, the lower the better. You want to aim for exit pupil and that means picking the longest focal length eyepiece you have. Some objects will take a little magnification, but don’t push it, especially on large objects.
Use Averted Vision
There is a blind spot in your eyes, and it’s right in the middle of your field of view.
Well, not precisely in the middle, it’s off to the side just a hair. There is a spot on the back of each eye where your optic nerve meets your retina, and there are no retina pixels there. This can cause problems when viewing.
You will be looking through the lens, spot a faint object to the side of view, and when you look directly at it, it vanishes!
It happens to all of us. The best thing to do is look again to the side of where you think the object is, and it will pop back into focus. Astronomers spend time getting used to this little quirk of human vision, and learning to pick details out of objects that they can’t focus directly on.
Another trick that can help is the scope bump. If you are sure there is a dim object to be seen in the view, try nudging the scope a bit to make the view shake. This little bit of movement can sometimes make really faint objects pop.
This skill will take practice, but the more you work at it, the better you will get.
Mind the Sky Conditions
Celestial objects will always look better when they are straight overhead rather than close to the horizon.
Clouds are an obvious problem, but people overlook other conditions such as pollen and dust in the air, as well as upper atmosphere effects. Sometimes, the views just won’t be that great. There are online sky weather forecasts, like the Clear Sky Chart, to help you along, or at least tell you why your view of Saturn is a bit wavy and cruddy.
The two conditions that will affect astronomy the most are seeing and transparency. These are influenced by factors that are beyond your control. Low transparency will reduce the contrast of faint DSOs while bad seeing will disrupt your view of planets and reduce your useful magnification.
Bad seeing is kind of like looking through the heat over the top of a barbecue grill.
Transparency also factors in light pollution, and is generally measured by how many stars you are able to see at the time.
Get More Viewing Time
It may sound a little silly, but the more time you spend behind the eyepiece, the more you will see.
I still remember Jupiter looking like a fuzzy ball the first time I laid eyes upon it. No matter how high I took the magnification, the view was the same. A bright disk with an orange stripe running across the middle, and four little sparkles representing the moons.
Now, when I look at Jupiter, even at low magnification, I can see storms and cloud bands and all kinds of detail. My eye had to learn what to look for.
Most of vision is based on previous data that we get from the world. The eye isn’t a camera lens, and doesn’t work like one.
As you learn more skills in astronomy, you will also see the same objects under better conditions, and each detail revealed has a tendency of sticking with the image the next time you look at it. This is why sketching and long viewing sessions can really help you see better.