How to - Choose the right telescope mount
Here at ScopeUout there is always plenty of discussion on optics; what strength and range one might want, what’s superior at night alongside many other topics. With such a large range of telescopes, sights, binoculars and scopes the conversation never seems to run dry. But recently a new conversation has begun to emerge. Stands and mounts. For what is a good telescope if you have nothing of quality to keep it steady? The discussion in the office has now leaked to our website as we take a look at the two main types of telescopic mounts.
There exists 2 main types of telescopic mounts: alt-azimuth and equatorial.
The alt-azimuth mount is what we’d refer to as a starter mount. It’s simple and easy to use and even easier to set up. However, it doesn’t have some of the better features that the Equatorial mount has, but we’ll cover this in detail later. The Alt-azimuth gets its name for the directions it operates in. Alt standing for altitude, its up-down movement, and azimuth being its left-right movement and no, we’re not sure why it’s called that either.
As you’ve probably guessed this type of mount has some major downsides to it. The first of which being that if you’re trying to observe stars you’re going to be constantly adjusting yourself as it struggles to smoothly track the stars as they sail across the sky. Not to mention with so many dials and leavers, operating it in the dark at night can become extremely tedious as you’re most likely going to need a torch to see what you’re doing… meaning you don’t have a hand to steady the mount as you try to fiddle with it. Also due to its simplicity it is highly unsuitable for more complex tasks, like astrophotography, as the long exposure of the camera means that the celestial point of interest has usually moved by the time the photo has been taken, thus ruining the quality of the photos.
There is a small solution to this however. Some Alt-azimuth mounts come with “goto” variants, in which a computer controls where the mount is facing and moving after you have initially aligned it. This means that it is less hassle to track the stars and keep a more even pace with them, meaning there is less over exposure.
To truly fix this problem your best bet is to change mount. What you’re really after is an Equatorial mount. It tracks stars perfectly across the night sky and all you have to do is adjust one axis. This therefore means you can focus more on observing the sky than screaming at a dial that you just accidentally hit your knee off. An Equatorial mount is must have for anyone considering long exposure shots for photography, there is nothing better.
There is strong science behind how Equatorial mounts work. Their entire concept is based around cancelling out the earth’s rotation. As the earth turns the stars move across the night sky, however the equatorial mount turns its axis the opposite way to which the earth turns; completely cancelling out the observed movement of the stars.
The only downside to this type of mount is setting it up so it can track properly. This can be a bit tricky and take some patience, but once it’s all sorted it will follow the stars beautifully, it’s just getting there that can be a pain. No matter your experience or your expertise setting any sort of polar alignment can be a pain.
For those of you who don’t like reading we will give you some final quantitative points on what mount is best for who.
An alt-az is best for:
- beginners who don’t want to much going on
- astronomers who want to move targets easily
- people who want to view land objects
- travellers who don’t have the time to complete a complicated set up.
An equatorial mount is best for:
- people who want to watch a single object all night long
- astronomers who want to use information already recorded to find targets
- astrophotographers who want to take long exposure shots of stars.
- Thomas Markham