Choosing the right telescope, particularly for your first instrument, is a difficult task and you may be tempted to turn to forums and facebook groups for help.
“Hi, I am new to this. What telescope should I get?”
An apparently innocent and straightforward question that will blow wide open the proverbial Pandora’s box:
Get a Dobson. No, get a Newton. A Frac will be better. What is it that you want to do? Get a binocular. Neither, consider the mount first! Yes, but what is your budget? Enough with these questions already, use google! (yes, some people get really annoyed about such posts).
And don’t even try to add to your question a link to that amazing and shiny $50 telescope found on amazon 🙂
The question, as such, is very poorly formulated. You would not go on the internet asking “hi guys, I am hungry. What should I eat?”, wouldn’t you?
But what is that you should know and say to ask that question in the proper way?
With this article, I will help you make the best informed decision for your needs. Or, at least, to ask a better question.
Do You Really Need A Telescope?
First thing first: I know you want a telescope but… do you really need one?
The observable universe, at 93 billion light-years across, is rather large and everything is so far away from us that of course you need a telescope. Or is it?
Funny enough, the things for which you really need a telescope are those closer to you.
How so? Well, size and distance defines the apparent size for an object, in this case, how large celestial objects appear to be in the sky.
Take the Andromeda galaxy. Sure enough is far, sitting about 2.5 million light-years from us, but is also 220 000 light-years in diameter.
On the other hand, the Moon is in our backyard, a mere 350 000 km from us. But the Moon diameter is 10 000 000 000 000 000 times smaller than that of Andromeda.
If Andromeda were bright enough for us to see it in all its glory, it would appear in the sky about 6 times larger than the full Moon. Unfortunately, we can only spot its bright core as an unimpressive small, greyish cloud.
A common 200mm telephoto lens, though, is long enough to show you the Andromeda core, the spiral arms, and the many dust lanes within the disc of the galaxy.
But take a photo of the Moon with the very same 200 mm lens, and you will not see much more than what is already visible at the naked eye.
For the planet it is even worse. Point your 200mm lens at Jupiter, the largest planet in our Solar System, and you will get a featureless bright dot with, if you are lucky, four even smaller dots around it: Jupiter’s largest moons.
For the planets you need a telescope, there is no other way.
So, if you are interested in photography and in deep-sky, you may be better off starting with a star tracker and your classic photographic equipment.
Get a telephoto lens around 3-400mm (or longer) and a photographic tripod, and you can start getting images of the entire lunar disc that show a good deal of details.
Finally, since the Sun has the same apparent size as the Moon, a simple solar filter on your longest telephoto lens and a tripod will be enough to photograph with ease the sunspots.
But to observe the Moon and to have a true immersive experience with the night sky, a simple 8×40 binocular is hard to beat, without all the complications and constraints of a telescope.
What Telescope Is Best For You? Test Case Scenarios
Ok, so you really want a telescope, but how to decide?
A few classic scenarios will help you to get familiar with the many options available on the market.
Telescopes For Kids And Beginners On A Budget
Kids are naturally curious and, sooner or later, they will start asking about those shiny things they see up there.
If you are looking for a telescope to initiate a young kid to the wonders of the universe, here is what you should look for:
- a budget-safe telescope
- a small and lightweight telescope
- a telescope that is easy to use and fast to set up
A small tabletop dobsonian like the Celestron FirstScope 76/300 telescope fits the bill perfectly and is by far the best option.
It is so easy, simple, and cheap that you can let your kid do the setup and everything, rather than just raise him/her to look through the eyepiece.
We grown-ups can also benefit from fast setup time and ease of use typical of tabletop dobson telescopes.
If you don’t have much space for storing your telescope, a tabletop telescope with a collapsible trousse design is a very compact instrument, for the dobson standard.
Among these compact dobsons, the SkyWatcher Heritage 130p Flextube 130/650, Skywatcher Flextube Heritage 150p, are a very good choice. The Orion StarBlast 4.5, while not collapsible, is still worth considering
These telescopes are a no brainer to use and so fast to set up, that will not be a problem to prepare everything for letting you comfortably observe the Moon and the planets even for quick sessions.
While portable, a dobson, particularly a tabletop one can be difficult to use in the field, far from the comfort of your garden.
If you often travel to a different location, the Celestron Starsense Explorer 127/1000 is a more suitable choice. This telescope comes with a computerized mount controlled by your mobile to easily frame your target.
While all these telescopes are meant for visual astronomy, you can take photos and videos with your mobile phone or compact camera using an adapter to hold it at the eyepiece.
Finally, if you want something easy particularly suited for planetary and lunar observation and photography, the Skywatcher Virtuoso can be a better choice.
This setup combines a very compact 90/1250 Maksutov telescope to a motorized tabletop alt/az mount, and you can attach a DSLR or planetary camera directly to the telescope.
Telescopes For General Observation
If you want to be serious about observing the cosmos, you may want to look at something more performant than the previous telescopes, with better optics and larger aperture.
A classic dobson is the best choice and great value for the money, as they offer the largest aperture you could buy with your budget.
It is not for nothing that dobsonian telescopes are called “light buckets”.
The Orion SkyQuest XT8 Classic dobson is a classic 200/1200 dobson. Similar telescopes can be found in the catalog of all the most common brands, from SkyWatcher to Celestron.
Dobsonian telescopes are reflecting telescopes mounted on an alt/az rocker box, which allows for a smooth and easy manual tracking.
But they are big and heavy, not easy to transport in location.
A more portable classic is the Celestron Astromaster 130/650 EQ, which is intended mostly for visual observations.
Same as for the classic dobson telescopes before, all major brands have similar Newton telescopes like the astromaster in their catalog.
Telescopes To Observe And Photograph The Moon And The Planets
Planets look very small in the sky. Even Jupiter requires long focal lengths if you want to see some details on its surface.
Once again, dobsonian telescopes pack both a long focal length and a large aperture, making it a good choice.
But if you limit yourself to the exploration of the Solar System, another kind of telescope can outperform a dobson in a more portable and compact package: a Maksutov telescope.
Maksutov are catadioptric telescopes characterized by a short tube, a low weight and sharp optics. Together with Cassegrain telescopes, they are often considered to be the perfect grab & go solution.
They offer superb views of the Moon and the Planets and can nicely resolve bright star clusters. But because of the long focal length, they have a high f-ratio, which makes them not ideal for faint deep sky objects.
Easy to use, a Maksutov can reach focus with almost anything you can attach to it, and the compactness and lightness of the tube means you can use them on relatively light mount too, both for visual and photography.
Skywatcher has a full line of Maksutov: 90/1250, 102/1300, 127/1500, 150/1800, and 180/2700 but, due to their weight, only the first two can be comfortably used on a SkyWatcher Star Adventurer (or similar trackers) and small computerized mount as the Skywatcher Az-GTi alt/az mount.
The Schmidt-Cassegrain Celestron Nexstar family offers a range of telescopes with computerized alt/az mount and are great alternatives to Maksutov.
Thanks to dedicated reducers, they can also be used for deep sky astrophotography if mounted on an equatorial mount.
All Rounder Telescopes
While it is not easy to find a telescope that performs great with every target, there are scopes that are reasonably good.
A good all-rounder telescope should offer a bright image thanks to a large aperture and a decent focal length.
Accessories such as dedicated focal reducers and wide-field eyepieces can improve the telescope performances on deep sky observation and astrophotography.
The Celestron C6 and C8 are compact and light Schmidt-Cassegrain telescopes that are great grab & go all-rounder telescopes, particularly the C6, also available in a bundle with a computerized equatorial mount.
The SkyWatcher 130 PDS and 150 PDS (also available in a bundle with a computerized equatorial mount) are two cost-effective reflector telescopes that are particularly suited for both observation and photography, thanks to a generous backfocus and a solid dual-speed focuser.
Refractor telescopes are great and more portable than classic reflectors, are easy to clean and do not need to be collimated. Also, refractors are often more contrasted than reflectors and may offer sharper images.
SkyWatcher has the EvoStar and Esprit line of refractors that are very good, with the Evostar 72ED being a favorite among enthusiast astrophotographers.
All major brands offer a complete selection of refractor telescopes. But they cost and weigh more than equivalent reflecting telescopes.
What Should You Look For In A Telescope?
So, with so many choices around, what should you look for in a telescope, to be sure you will buy the right one for you?
Common Features To Look For
Telescopes come in different designs and variations, but they all share some important features you should carefully consider before you pull the plug on a particular setup.
Aperture is king!
In the world of telescopes, with aperture, we define the diameter of the front lens or opening, depending on the telescope design.
The aperture is fixed, and the larger the telescope, the more details you can see and the brighter the image is.
Also, a large aperture telescope allows for a greater magnification limit.
As for photographic lenses, the longer the focal length, the larger the target appears to be in the field of view of the telescope.
Long focal length telescopes are ideal for lunar and planetary observation and photography.
But are they good for getting close to deep sky objects? For this, the f-ratio is crucial
The ratio between the focal length and the aperture of a telescope defines its f-ratio and, same as with photographic lenses, the lower the f-ratio, the brighter the image.
Moon and planets are fairly bright, and it is not uncommon to use setups with an f-ratio of 20 or more.
But deep sky objects are very dim and to visually observe them you need a fast telescope, something in the order of f/5.
With a camera you are not limited to the light gathering capability of your eye. However, even so, you still want to collect a fair amount of light in a reasonably short time and a fast (low) f-ratio definitely helps.
That said, you can see why it is difficult to do deep sky observation and photography with a long focal telescope. My Skymax 1250/90 is a f/14: a fast f/5 telescope with the same focal length would have an aperture (diameter) of 1250/5 = 250 mm.
Not a small, light and/or cheap scope.
All telescopes have some sort of optical aberrations: coma, field curvature, or chromatic aberration.
They are not a deal breaker for visual observation, but for photography, you need to take care of them.
Fast reflectors suffer from coma, and if you want to use them for photography, you have to have a coma corrector.
Achromatic refractors suffer from both field curvature and chromatic aberrations. A field flattener (sometimes combined to a focal reducer) is necessary to improve deep sky performances.
Apochromatic refractors make use of low dispersion ED lenses to reduce or eliminate chromatic aberration.
All these “fixes” come at a cost, and you should consider them when deciding your budget, particularly if you intend to do astrophotography with your telescope.
The focuser allows you to focus the image when you photograph or look through the eyepiece.
There are different designs available, from the simple helical focuser to double-speed crayford focusers for precise focusing.
Cheap focusers will not support the weight of a camera and are not really useful for astrophotography.
Another thing to consider when shopping for your telescope.
How far back a telescope can focus the image will decide if it can be used for astrophotography.
If the back focus is very long, you can use extension tubes to place the camera sensor at the right distance from the scope, but if the back focus is too close to the back of the telescope, you will not be able to achieve focus.
Budget newtonian telescopes are meant for observation only and their back focus is too short for reaching focus with a camera.
The only option for using a camera in prime focus is to use a barlow lens, which extends the back focus of the telescope, but this comes at the cost of working with a narrow and darker image.
In this case, it is better to work in eyepiece projection mode, with a small compact camera or your camera phone held at the eyepiece with a proper mounting adapter.
The Celestron NexYZ is my favorite adapter for a camera phone, but is heavy so your focuser must be good enough. Not a problem with Maksutov telescopes, though, as the eyepiece is not on the focuser.
The mount you will put the telescope on is as important as the telescope itself, if not more.
The mount must be able to comfortably support the weight of the telescope plus accessories and to allow you to reliably track the motion of the celestial bodies.
This can be done either manually (mostly for observation with budget equipment) or using precise motors (a must for astrophotography). Computerized mounts with GoTo capability are for high-end setups.
As a rule of thumb, the larger the scope, the sturdier the mount must be and this comes, once again, at a cost.
For astrophotography, it is commonly accepted that the total weight of the equipment should not exceed the 50% (or 75%) of the declared maximum payload for the mount.
The type of mount is crucial.
Alt/Az mounts are perfect for visual observations, but they are not the right kind of mount for astrophotography.
If you want to photograph, you need to take long exposures and for this you need an equatorial mount.
As opposed to alt/az mounts, the equatorial ones not only track the movement of a target across the sky, but it also compensates for the field rotation.
Size And Portability
Finally, there is the question of size and portability. A complete setup can weigh anywhere from 2kg to 100kg.
And the telescope size can range anywhere from 30cm to over a 1 meter or more.
When you shop for a new telescope, ask yourself these questions:
- Do I have the space to store the whole setup?
- Do I need to move the gear to a darker location, or can I observe/image from my place?
- Do I need to hike with my equipment?
What Are You Most Interested In?
We have left for last what perhaps is the most important question you should answer.
What do you want to do with your telescope: observation or photography?
While telescopes come in many flavors (designs), roughly speaking, they all let you see up close things that are far and look small in the sky.
If before starting reading this article you could think you would be able to see and photograph with any of them, it should be clear by now that this is not true.
The reason for this is that for a given application, you have to consider the whole package: the telescope and the mount it sits on.
To observe, you could do with a setup as simple as a small telescope sitting on a ball head: it will be frustrating to keep the target in the frame, but with the planet is still doable.
Most of the dobsonian telescopes commonly recommended for beginners wanting to observe the night sky are mounted on large and smooth alt/az mounts for manual tracking.
If you want to photograph with a telescope, particularly deep sky, you need much better equipment.
A motorized equatorial mount large enough to comfortably support the weight of the telescope and accessories is a bare minimum.
But a computerized mount with GoTo capability and a guiding system is highly recommended.
Observation Vs Astrophotography: Which Is Better?
Observation and astrophotography are very different. Observing is probably cheaper, less demanding on the equipment and on your time and skills than photographing.
But before discarding the possibility of using the equipment for photography, realize that even the largest telescope will not let you see things as in photography.
You are against the limit of the human eye, which is not very good to pick up faint light, particularly if its source is small. And forget about all those nice colors too: most of the time you will see greyish puffy clouds with some details.
Also, to observe deep-sky objects, you must be under a decently dark sky (Bortle 3 or lower).
Still, observing can be a great experience for viewing the Moon, the planets, double stars, and globular clusters.
What Is Your Budget?
I am more of an astrophotography enthusiast than a visual astronomer, but I can say that of the two, chances are astrophotography requires the bigger budget.
You can, of course, do astrophotography on a budget, with a star tracker such as the Skywatcher Star Adventurer Pro, your DSLR, and photographic lenses, but in general, in the long run, photography will cost you more than observation.
A decent dobsonian telescope for observation, with a couple of eyepieces and a red dot star finder, can cost you around 200 euros, new. To that, add a barlow lens and an adapter to snap some videos with your phone and you are good to go.
Sure, you can then improve the quality of the eyepieces (and some are not cheap), but let’s say that at 3-400e, you can have a good amateur setup for visual observations.
If you want a motorized mount, maybe with a GoTo capability, then you have to double or triple that budget.
For astrophotography, a tracker that will allow you good flexibility will set you back of about 400e.
But if you are mainly interested in starry landscapes and milky way shots, you can start with the Omegon Minitrack LX2 for as little as 200e with the required ball head and wedge.
A budget of 500e will let you photograph with lightweight photographic equipment, as no telescope will fit on a tracker.
Some notable exceptions to the previous statement are very light refractors like the William Optics Red Cat Z51 and Maksutov telescopes like the Skywatcher Skymax 90/1250
Full-grown astrophotography mount will set you back by at least 700e, particularly if they have GoTo.
Finally, a word about the many bundles (mount + telescope) you can find on the classic webshops: while the price tag can be interesting, understand that many combinations are really suitable for observation only. The mount is not usually good enough for deep sky astrophotography.
Astrophotography is very demanding compared to visual observation.
Types Of Telescope
The first astronomical use of a telescope dates back to Galileo Galilei. With as little as 30x magnification, Galileo and its telescope paved the road for modern astronomy.
But the term “telescope” is a very general one, and it is used to indicate any optical instrument able to magnify distant objects. In practice, there are three main designs of telescopes and many more variants of those designs.
Each has its own set of pros and cons.
Reflecting Telescopes (Reflectors)
In a reflecting telescope, the image is collected from the front opening, reflected by the primary mirror at the back of the telescope to a secondary mirror on the front, which reflects the image towards the eyepiece or the camera.
As large mirrors are relatively cheap, this kind of telescope has a great value for money, but for maximum performances, mirror collimation must often be checked and, eventually, recovered.
Newtonians (and Dobsons), Cassegrains, and Ritchey-Chretien telescopes are all reflectors.
- Good value for money
- Affordable large aperture telescopes
- Fast f-ratio
- Great for visual observations
- Need for periodic collimation
- May suffer from coma
- Not always suitable for astrophotography
- Diffraction spikes on bright stars
Refractors work the same as photographic lenses, with the light being collected and focused by passing through a series of lenses.
Because of the use of lenses, the design is more complex than that of reflectors and refractors are more expensive, particularly when low dispersion glass is used to correct chromatic aberration.
But because of the use of lenses, the size of a refractor is much more compact than that of an equivalent reflector, so they are highly portable.
Also, being the tube smaller than that of equivalent reflectors, the cooling time is minimum and the instrument is ready to use with no delay.
Not having mirrors, collimation is not an issue and maintenance is reduced to just keep the optics clean.
- Great performances
- Suitable for astrophotography
- Short cooldown time
- Very low maintenance
- May suffer from field curvature as well as chromatic aberration
Catadioptrics Telescopes (Compounds)
In a catadioptric telescope, light is both refracted and reflected as in this design, a lens is combined with a curved mirror.
The most common catadioptrics are Maksutov-Cassegrain and Schmidt-Cassegrain telescopes.
- Good value for money
- Relative large aperture
- Contrasted and crisp image
- Little maintenance
- Best for lunar and planetary observation and astrophotography
- Often they have a high f-ratio
- Some are not very suitable for deep sky observation and astrophotography due to the high f-ratio
- Long cooldown time
A Short Video To Guide You In The Choice Of Your First Telescope
This great video by J. Kelly Beatty from Sky and Telescope Magazine, nicely summarises what you need to know and to consider for making the right choice.
As you see, the choice of a telescope is not for the faint of heart: many concepts play together when looking for the right instrument and the right setups for your intended use, and this article has just scratched the surface of what there is to know.
But at least now you know how to pose your question properly: always state your expectations, budget, and intended use when asking for help in choosing a telescope.