Since I work with the public on a regular basis, I get asked questions about telescopes all the time. The following are the most common questions I get.
What is the Magnification Power?
The magnification is determined by the focal length of the telescope divided by the width of the eyepiece you’re using.
Most people ask this question not knowing that magnification power is actually the LEAST important aspect. Most telescopes are designed to operate with low power, and when you add high magnification you sacrifice light and sharpness, plus the turbulence in the atmosphere starts to take over and make objects look a little wavy.
Do I Need an Expensive Telescope?
No, you don’t.
However, don’t let the department stores fool you!
If your budget is less than $100, I will recommend to invest in a good pair of binoculars instead. Scanning the night sky with binoculars is still a joy unto itself, as it reveals things in the sky you never thought were there.
Beginner telescopes that have a decent amount of aperture and give good views of the moon, planets, and several bright deep sky objects will only cost a couple hundred dollars to start.
The money starts adding up when you go for more advanced telescopes.
Why Can’t I see Anything?
- Are the dust caps off? That might be the reason everything appears black.
- Are you properly looking through the eyepiece? Remember, it’s the one that goes into the tube, or the diagonal.
- Is telescope actually pointed at the desired object and is it in focus? Sometimes if the telescope isn’t automatically tracking, objects fly out of your view due to the earth’s rotation, especially when using higher magnification which narrows your field of view.
How Did you Find That?
- Bright objects like the moon, planets, and bright stars, are relatively easy to find, and can often be “eyeballed” through the telescope without too much technique.
- Deep Sky objects, which are usually not bright enough to be seen with the naked eye, are found by knowledge of the stars and constellations.
- In the 20th century, we used star maps and guide books on paper. Nowadays, smartphones have apps that do all the help for us!
Can You View the Sun Through Your Telescope?
Yes and No.
Telescopes actually focus and magnify incoming light, and will blind you in less than a second if your eye is not properly protected by solar filters.
The same applies for cameras, which can melt due to the focused light!
But if you do have them, usually installed to the front of the tube, then looking at the sun through the telescope will be safe for your eyes and cameras.
“Why Are You Only Looking At the Moon?”
A man asked me that one night out of disappointment at Griffith Observatory while I was showing a full moon to the public under a light polluted Los Angeles sky! He then followed up with “Why wouldn’t you use this telescope to look at galaxies?”
The moon often washes out deep sky objects such as galaxies in the night sky, and a full moon is usually when astronomers leave the telescopes inside.
Cities, especially the lights from Los Angeles, also wash out the night sky, making deep sky viewing nearly impossible.
All the man had to do was do the math!
Why Aren’t You Looking At the Moon?
Because it’s not out right now!
Can You Point to the Lunar Lander?
No. The moon is on average about 240,000 miles away. None of the earth based telescopes can resolve features on the surface of the moon that small. Not even the Hubble can resolve anything smaller than 300 feet, and the largest object left on the moon by astronauts was 14 feet wide.
However, NASA’s Lunar Reconnaissance Orbiter (LRO), a satellite that can dip as low as 31 miles above the Moon’s surface, has a telescope that can easily resolve the landing sites in good detail! Some of the sites still have tracks left behind their rovers!
Go look it up!
Can You Show Me a Planet?
Here are my two possible answers:
- Sure, it’s not a problem.
- None of them are visible in the sky right now. You can either wait for later tonight, or wait a few weeks to a few months.
Why is This <Deep Sky Object> so Dim?
If it isn’t already washed out by moonlight or light pollution, there is two possible scenarios:
- You’re viewing with a small telescope, which doesn’t allow as much light as larger telescopes.
- You’re viewing at a high magnification, which allows less light and thus it isn’t as easy to see.
- The object is merely too dim and/or far away, and can only be easily seen through astro-photography.
Many deep sky objects are notorious for being disappointments through telescopes due to their dimness and/or distance. The human eye is what is to blame, since it continuously re-shutters to allow only enough light exposure into the eye to function. Cameras on the other hand can be set for long exposure, and thus allow more light and more detail to be seen.