Choosing a first telescope

Choosing a first telescope

Getting your first telescope is a big moment in the life of any astronomer. Here I’ve gathered together some questions I think it can be useful to mull over as you tackle the selection process.

One of the most common questions I’m asked by people just getting into astronomy is “what telescope should I buy?”. It’s actually a deceptively complex one to answer. For starters, and for reasons I’ll expand on in a bit, I’ve never really felt that generic recommendations of a particular ‘beginners’ model are that useful – even if it’s a good scope that I have direct experience with. And as you’ll see in my ‘Getting started in stargazing‘ guide, I don’t believe a scope is absolutely necessary (or, indeed, always the best option) for someone just starting out anyway.

Part of the reason why it’s a tricky question, and why I prefer not to give one-size-fits-all suggestions, is that which scope is ‘right’ for any one beginner depends on many factors. These are often highly interdependent and can vary greatly from person to person. The numerous designs, mounting arrangements and even apertures available can also have various advantages or disadvantages in different contexts.

Rather than try to detail here all the pros and cons of every single kind of setup – which would likely fail to fully capture these nuances, while not actually making the process any easier – I thought it would be more useful to look at how you might effectively steer the broader decision-making process.

To this end, what you’ll find below are a series of things that I think can be helpful to reflect on as you begin searching for your first scope; essentially they’re what I’d ask you if you came up to me and posed the ‘which one’ question we began with. My main piece of advice in all of this would be to get really clear in your mind what your thinking is on each point. Among other things, careful consideration at this stage should help you ‘future-proof’ your first setup as well as make the most of your budget. From there, I’d recommend speaking to a reputable telescope dealer, as they should be able to give you their advice on specific designs & models that match the interests and requirements you’ve identified.

Have a look, and see what you think…

🔭 Who will actually use the telescope

Is it for you, a family member/friend or, perhaps, a child? In which case, consider how that might affect the size and complexity of the potential instrument. Viewing position is a key thing to think about here, as the eyepiece on some telescope designs can sometimes end up positioned at awkward heights/angles. Will the observer be able to manoeuvre/reach up to a large scope or the eyepiece safely and without frustration? And once at the eyepiece, will they actually have an interest in the types of object this telescope is able to show?

🔭 If there are particular celestial objects you want to observe

This will often quite dramatically influence your choice. There are designs that work well across a range of targets, but if you have a clear idea of what you want to look at it can direct you more efficiently to specific designs and models (and also use your budget more effectively!) For example, if you’re really keen on just visual observing then that’ll almost always push you towards simple scopes with larger apertures, like those referred to as ‘Dobsonians’, and everything that entails.

🔭 Where you think your interest might take you in a few years

This, in my opinion, is one of the more important points here and a good example of how most of these factors are extremely interdependent. Have a think about where you see your interest taking you in the future. Is this scope going to be part of your observing kit in years to come? How might it fit into such a collection? Can it be adapted, upgraded or put to use as part of an imaging rig – say, as an auto-guiding scope? Can the mount the telescope comes with be used with a more advanced visual setup, if desired (things like mount carrying capacity and saddle profiles are things to consider here)?

🔭 Whether you want to do astrophotography (now, or in the future)

If you choose your first scope carefully, it might be able to be incorporated into an astrophotography setup later on, if you develop an interest in taking images. Maybe you want to take astrophotos from the outset, in which case you’re going to want to look at both the scope’s suitability for imaging (including everything from its connectors to optical characteristics – for example, in deep-sky imaging, how ‘flat’ and evenly-illuminated the field is with your camera) as well as the mount’s capabilities e.g. its motorisation, auto-guiding ports, polar alignment scope/reticule etc. Think about what you want to image too, as there’s a big difference between a setup optimised for lunar and planetary imaging and one for deep-sky astrophotography.

If you want to do astrophotography you’ll have to think carefully about the selection of the mount your optics sit on, not just the scope itself.

🔭 Your mobility

Large-aperture instruments and their mounts tend to be bulky and extremely heavy. Will you be able to handle and move the scope around safely? And if you need to travel to an observing site regularly, how easy will that be with the specific kit you’re considering? In the long run, would a simple, highly portable, setup provide more use and enjoyment than something more complex?

🔭 The location where you’ll typically be observing

This is an important thing to consider in terms of accessibility and safety, but also because local light pollution levels can influence your selection, or at the least the vague direction of your interest. Will the things you want to observe actually be visible from this location with this scope? Do you need to budget in visual observing filters to reduce the effects of light pollution and increase contrast? Would an imaging-orientated setup be more suitable? Are there targets which lend themselves more easily to observation/imaging from this location, and if so what sort of scope do they require?

An example of a highly portable visual observing system that’s quick to set up.

🔭 How much free time you have

If you don’t have a lot of free time, you’re probably not going to want kit that takes the best part of an hour to get ready for observing or imaging (such set-up times are not at all unusual in astrophotography, particularly deep-sky work). Here, you’ll want to reflect on the mounting system that the scope sits on, as it’s often the size, complexity and build quality of the mount that determines setup time.

🔭 Your budget

How much you think you’ll spend can obviously affect what scope you go for, but note that it’s not always the most expensive setup that is the better one for a particular person…

🔭 What your knowledge of the night sky is like

If you’re already a fairly confident stargazer who knows your way around the night sky, you might not necessarily need kit with an advanced electronic pointing system. Does a simpler push-to arrangement or one with manual/basic electronic controls suit you better? That’s not to say that if you aren’t familiar with celestial navigation that you should always opt for advanced ‘go-to’ systems either. Think about what such electronics bring to a setup and how you’d use them.

While the list above doesn’t quite cover everything, if you can pin down as many of them as possible I think you’ll stand a much better chance of selecting a piece of kit that’s right for you.

As you navigate which scope to go for, keep in mind some of these other important things:

I’ve used the word ‘aperture’ here several times. This just means the diameter of the main (or ‘primary’) mirror or lens in the scope. For example, this would be the front lens on the refractor scope in the animation on the right or the large mirror at the bottom of the tube in the reflector below it.

[Left] A sketch of three galaxies made at the eyepiece of a 203mm (8-inch) aperture scope, which would typically be considered a medium-aperture instrument.

Generally speaking, the larger the aperture the better a telescope is for astronomical observing. That’s because larger apertures can gather more light than smaller ones, which means that faint things like galaxies and nebulae become easier to see. Larger aperture scopes also enable you to view finer details on objects like the Moon and planets.

What’s the difference between a refractor & reflector telescope?

A refractor telescope uses a system of glass lenses to gather
celestial light and direct it to the eyepiece (represented by the
black cylinder in these animations).

Credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)

The light path of a so-called ‘Newtonian’ reflector. Reflectors use
mirrors to collect & focus light from astronomical objects.

Credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)

The two kinds of telescope mount you’ll commonly encounter: Alt-Az & equatorial.

An alt-azimuth or ‘Alt-Az’ telescope mount following a celestial target
by turning on its azimuth axis as well as its altitude axis.

Credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)

An ‘equatorial’ mount following the sky by turning on a single axis (since the
mount itself is ‘polar’ aligned so one axis is parallel to the Earth’s axis
of rotation).

Credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)

As I touched on in the list above, it’s not just the optical system of a setup that you need to put some thought to when choosing a first scope. The mount and tripod arrangement that the telescope is carried on are hugely important components too – I really can’t emphasise this enough.

There is nothing more frustrating when observing at the eyepiece than a mount that flexes or isn’t sturdy. Pointing the scope accurately will be hard if the mount isn’t up to scratch and, worse, the view through the eyepiece will slop around, which gets really annoying very quickly. Good mounts are rock solid with controls that move smoothly with precision.

Finally, do think about how much you’ll really need any of the electronic gadgetry that’s occasionally built into beginner’s telescopes.

Modern so-called ‘go-to’ technology – which typically aligns, calibrates and points the scope, often automatically – is brilliant, don’t get me wrong, and it can often speed up finding and locating celestial objects, if it works well. But its inclusion in a basic setup can add a substantial amount to the cost of a rig. That’s money that has the potential to get you a scope with a much larger aperture, if it was included in the budget for a system with a simpler mounting arrangement.