Why Your Telescope Mount is More Important Than the Scope
What is a Telescope Mount?
A telescope mount is a combination of a base or tripod plus a system of gears and attachments that hold the scope in place and allow it to pivot on its tripod.
The types and varieties of mounts vary, but for most amateur and advanced astronomers there are five kinds of mounts.
- The Handheld Mount – For binoculars or other handheld viewing systems
- The Alt-Azimuth Mount
- The Dobsonian Mount
- The Equatorial Mount
- The Equatorial Fork Mount
There are other variations that are used for extremely large scopes and radio-astronomy dishes, but for most of us these 5 define our playing field.
They have advantages and disadvantages, and in the case of equatorial mounts there are some variations we should consider. What’s critical to understand is that the right mount may be more important than the scope.
If many of us had it to do all over again we would not have bought that telescope in a box from the big-box store. Sure it looked impressive and touted a magnification of 600x.
Unfortunately we neglected to understand and respect the mount for the scope. What we learned quickly was that the scope was simply incapable of following any celestial object at high magnification including the moon. The reason was simple.
The mount and gearing for the telescope tube was incapable of accurately and easily tracking across the sky as the Earth rotated on its axis.
To make matters worse, near Earth objects like the moon and planets have their own orbits that often move in angles and vectors that are both vexing and complex.
What’s the answer?
Invest in a good mount!
Most scopes can easily be attached to any mount.
The fact of the matter is that you could take the most fundamental scope and put it on a good mount and see extraordinary objects in the sky. Take the most expensive refractor you can buy and put it on a bad mount and you have wasted your money and your time.
It’s simple but counterintuitive.
Spend more money on the mount than the scope.
You can always upgrade the scope and attach it to your very good tripod and mount.
So which Mount Should I Choose?
We’re going to explore a range of mounts for various scope types, but if someone asked this question on the street our response would have been “equatorial.”
But let’s get back to the top five and work towards equatorial.
There are many objects in the sky that can be easily viewed with handheld binoculars. The moon, comets when they make their rare appearances, The Pleiades star cluster, even Jupiter and Saturn although they’ll appear quite small in the field of view.
Some people attach their binoculars to a simple camera tripod and others have even attached a DSLR camera with a telephoto and taken fairly dramatic photos of the moon such as this one taken with a Pentax X5 camera with a 100mm zoom telephoto:
While binoculars and DSLR cameras give us some fairly good views of the moon, a telescope on a good mount is the best bet for viewing the planets and deep space objects.
The Dobsonian Mount
It is typically a very large tube reflector mounted on a fork mount that pivots. This is commonly referred to as the “Dobsonian Mount”.
Dobsonian mounts typically are adjusted manually to track celestial objects. This is easier than a standard refractor or reflector because the Dobsonian telescope has a very wide field of view.
Another benefit of the wide-field is that as objects move across the sky they will stay in the field of view longer simply because the Dobsonian scope reveals so much of the night sky even at higher magnifications.
If you’re not sure if a Dobsonian is right for you, see if you can look through one with an amateur astronomy club or do some good research on the Internet.
There are more sophisticated “Dobs” that can be rigged with a motor drive, but most depend on manual manipulation to track objects across the sky.
The Alt-Azimuth Mount
Also known as the Altitude-Azimuth Mount, this mount allows you to track objects based on their altitude (Up and down or North and South), and their azimuth (Left and right or East and West). Unfortunately, few objects move in perfect North/South or East/West lines.
Most take an arcing angle across the sky that requires a compound move that adjusts the scope as the Earth and/or the object traverses the sky. This means we have to adjust for North/South and East/West simultaneously.
It can be done, but it can get tedious and frustrating at higher magnifications.
Something else we learn very quickly is that what we see through our scopes is actually upside down. As a result the adjustments we make by hand or with adjustable knobs have to move the scope in the opposite direction we would suspect.
There is a way to correct this with something called an erecting prism but it will diminish the light transmission through your scope.
Curiously, a telephoto lens on a camera does not have this aberration, but most scopes present the image inverted. It’s simple to correct with astrophotography if you’ve taken a picture through your scope. Just turn the image upside down and you’ll have the correct view if you took the photo through the scope.
The alt-azimuth mount is found on many amateur scopes and while they do allow you to manually adjust and track an object across the sky, they fail with any attempt at long-exposure astrophotography simple because the tracking adjustments we do by hand are coarse and inconsistent.
The Equatorial Mount
Perhaps the best mount for amateur astronomy is the Equatorial Mount.
If you are considering astrophotography it’s a must have when combined with a motor drive or computer drive.
There are different styles of Equatorial Mounts but one of the most popular is the German Equatorial Mount or “GEM” for short.
It features a large counterweight that is used to offset the weight of the scope and allow the telescope to easily pivot on the mount. This is the mount that is usually combined with a motor drive or motor drive connected to a computer.
Like all equatorial mounts, it has to be aligned with the North Star in the northern hemisphere to accommodate the arc of celestial movements across the sky. Any scope with an equatorial mount should have sufficient instructions to help you make this alignment regardless of where you are on the planet.
The intent is to offset the rotation of the Earth while you track objects in the sky, especially deep space objects which tend to follow the arc of the polar axis. The Moon and planets sometimes require additional adjustment given their relative proximity to the Earth.
Other types of Equatorial Mounts include the Equatorial Fork Mount and some more advanced configurations for very large scopes such as the Poncel Mount.
For most amateurs, a German Equatorial Mount or a Equatorial Fork Mount are the most popular.
The Fork Mount is actually very popular with some amateur astronomers and can be combined with an automated motor drive sometimes referred to as a “hand-paddle.” This allows you to select an object by certain coordinates and the scope will automatically turn to find and track it.
Unfortunately, if your alignment or coordinates are off, it’s very difficult to adjust the scope and search for the object. Some people especially owners of Celestron telescopes swear by them.
They will also allow you to do some long-exposure astrophotography but any exposure over 30 seconds may get some blur or star-trailing.
So which mount is right for me?
It’s fair to say that any mount will work for the casual, amateur astronomer but if you want to explore deep space, do some advanced astrophotography, or feel you may upgrade to a better scope someday – the German Equatorial Mount is your best bet for long-term use and performance.
Some amateurs when purchasing their first scope prefer the Fork Mount.
That’s up to you, and If your scope has an Alt-Azimuth Mount, don’t despair. You’ll be able to find and track many celestial objects but you probably won’t have much success with any astrophotography exposures over a second and even that’s pushing it.
Just remember that a German Equatorial Mount is going to require some instruction and practice to get the alignment and coordinates right. Once you’ve mastered those basics you’ll be in a good position to explore just about anything the night sky has to offer. You’ll also be in a good position to attach other scopes or future upgrades to your mount with the same precision you’ve enjoyed in the past.