Mounts Basics

Mounts and bases are essential for stargazing, because they hold up the telescope and keep it fixed. Most telescopes come with a mount that is made for that specific make, which makes life much easier, especially for newbies. There isn’t much need to go into depth about mounts, but it is important to know the main types of mounts.

Altazimuth mounts are quick and easy to operate. The word altazimuth is a combination of altitude and azimuth, hence they allow the telescope to move up and down (change altitude of the piece of sky observed) and side to side (change the azimuth of the observed sky). The movement is driven by hand with this mount.

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My old altazimuth. It is much more sturdy than it looks, considering this mount is just held together by cheap screws and adjusters!

The altazimuth is fantastically cheap, and are quite steady since stress is balanced out well. For medium to small scopes, there isn’t a need for counterweights, since the mount holds well by itself. Most telescopes use these mounts, and I definitely recommend this one for anyone regardless of their budget, and you can buy motors for the mount if you do end up interested in tracking objects, for still quite a low cost. Calibrating the movement correctly is very fiddly with motors, so be careful!

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The altazimuth doesn’t have counterweights, unlike the equatorial. If you have a large and heavy telescope, counterweights are ideal.

Some variations of this mount, such as the Dobsonian mount or the fork mount used for catadioptrics, are difficult to transport since they can’t fold away.

The other main type of mount is the equatorial mount, where the telescope is aligned with either the North or South pole, and also the celestial equator, in which a motor drives the calibrated scope around the sky.

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This is a Meade Equatorial mount. Notice how it has a counterweight. The Equatorial mount turns differently to the altazimuth, it spins around a set point.

It is very useful for tracking objects. Since it’s always aligned at a pole, it is aligned with our rotational axis, and makes motorised movement less of a hassle. Undoubtedly it is a must for astrophotographers, as long exposures mean target objects must be in place for long periods of time. The motor-driven scope is also great for those who want to just enter coordinates and find an object, although aligning the telescope an be quite time-consuming, so it is best to do that in daytime.

These mounts can also come motor-less, but moving the scope becomes very difficult to do accurately, which is why this mount will have long flexible controllers, that do fine-tuning much better than the human hand.

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An Orion AstroView mount. The straight line is the polar axis. The mount turns around this axis, which is useful for looking at stars over a long time.

 

Buying just the motor itself can cost a lot, and the altazimuth definitely beats the equatorial in price. I also find that the equatorial doesn’t give me the freedom that I want when observing; once the mount is aligned, it stays aligned, and I personally like the fact that I can just swing the altazimuth around to random places and not worry with counter-weights and whatnot. However, the equatorial is amazing at keeping track of objects and once it’s set up is very low-maintenance.

Looking specifically at variations of mounts, cassegrains normally use a short bulky mount called a Fork mount. Fork mounts do have a large advantage to other mounts: it can have both an altazimuth and an equatorial setting, so it provides the best of both worlds!

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A Celestron Cassegrain on a fork mount. This one is already computerised.

Dobsonian mounts are super easy to use. There’s no need for alignment or setting up, just put the scope on the mount where the bearings slide in, and you’re ready to go! With the right measurements, you could even make a mount yourself, lowering the cost further.

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A Sky-Watcher Skyliner and its mount.

Remember you don’t want a small gust of wind to blow the telescope out of place, so a mount that is the right size for your scope is essential, especially for those wishing to take photos of the sky.

The best way to pick is to remind yourself of what you want out of amateur astronomy and follow on from that. If you are a budding photographer, perhaps try finding an equatorial to make sure you can take long exposures and get crisp shots of deep-sky objects. Or if you like to just point your telescope at different areas of the sky and see what there is, an altazimuth may be the better choice.

Happy Stargazing!

One comment

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