The two most common types of telescope mounts available on the market for backyard astronomers are AZ and EQ. With very rare exceptions, these are the two types of mounts that you are going to come across in your research into a new telescope. Which one is better? Is there a big difference between the two?
If you are scratching your head over the differences between AZ and EQ or if you don’t know what these terms mean, do not worry.
AZ stands for altazimuth mount and EQ stands for equatorial mount. Both are different types of mounts for your telescope that behave in slightly different ways.
An altazimuth mount is able to move fully on both major axes. An equatorial mount is designed to be aligned and then moved along only a single axis. This gives you two completely different viewing experiences based on a similar looking design.
AZ = Altazimuth Mount
Altazimuth mounts are some of the most common mounts for both astronomy and photography. It is a simple manual mount that allows you to move the telescope upwards, downwards, left and right. This gives you the freedom to move the telescope freely across the sky without any constraints, alignment, or calibration necessary.
This is the type of mount most people will think of when they think of mounts in general. It can be found everywhere from a basic tripod to a Dobsonian base. It is used for mounted TV cameras, professional photography, and astronomy.
People like the altazimuth mount because of the freedom and fluidity of movement that it offers.
EQ = Equatorial Mount
Equatorial mounts are similar to altazimuth mounts but they lock one of the axes of movement so that the telescope only moves along a single axis. This is done in order to allow for easier tracking of night sky objects.
Once one of the major axes of movement is locked into place, you can align your telescope with the equator which then makes it so the sky is going to be rotating overhead in a more manageable way.
Equatorial mounts allow for micro-adjustments which can keep your favorite sights in the eyepiece for hours at a time. Once you only have to account for a single direction of movement based on the rotation of the Earth it becomes super easy to ensure that you move your telescope manually at the same speed.
The equatorial mount sacrifices freedom for slow motion tracking.
Which Is Better?
At the end of the day, which is better is going to be up to you depending on what you are trying to get out of your telescope experience. If you are looking for a more freeform and relaxed method of star scanning then you might prefer the ease of the altazimuth mount. If you are looking to get some stunning views of Saturn and keep them in view for hours on end then you might prefer the structured usage of the equatorial mount.
The equatorial mount does require some alignment and basic calculations to get set up properly. Once you learn, it becomes a breeze but at first, it can be a little daunting. You have to find the equator, think about which objects you want to find and track and then align your telescope in the correct position with the mount.
Once you get it right, you can keep specific objects in view with a simple turn of a nob over the course of an evening.
The downside is, if you decide you want to change vectors or want to swing your telescope around on a whim, you aren’t going to be able to do that. For example, if you are looking at Jupiter but then a new star catches your eye, it is a lot harder to reposition the equatorial mount than it is the altazimuth mount.
What are the trade offs?
The trade off is, the altazimuth mount can be hard to keep still and in place for long periods of time. That means, if you do get a great image of Jupiter with the AZ mount, it will take a lot more concentration and fiddling to keep it in sight for more than a small amount of time.
If you bump an altazimuth mount it can set you back minutes or longer of searching to find exactly where your focus was in the sky because you will move the telescope out of position
One is not objectively better than the other. Which you prefer is going to depend on what you are looking to do. You might even enjoy the features of an equatorial mount one night and prefer the feeling of an altazimuth mount another night.
Mount Versus Optical Tube
The first thing to note is that the mount of a telescope has nothing to do with its optical tube assembly (OTA). That means that whether a telescope is AZ or EQ has nothing to do with what kind of telescope it is or the optical quality of the telescope in general.
You can have both AZ and EQ mounts on telescopes that are fifty dollars or five thousand dollars. It has no bearing on what the actual telescope is. In terms of comparison, we are simply comparing the uses of the mounts themselves and nothing about the OTAs that they may or may not be attached to.
If you are savvy and inclined, you could swap the mount out for any of your telescopes and move between an EQ mount and an AZ mount.
An altazimuth mount is a freeform mount that allows you to move your telescope in any direction with ease. An equatorial mount locks one of the axes of motion and aligns with the equator to make it easy for you to track objects as they move across the sky throughout the night. Both are great in their own right and both offer some benefits over the other.
At the end of the day, which one you like or need will be completely up to you.