FREE SHIPPING ON MANY PRODUCTS

The Telescope Authority
Since 1947

Introduction to Telescopes

Before we dive in to the wide world of telescopes, we want to quickly share two great guides for beginner & kids' telescopes that we personally recommend here at OPT. If you'd rather skip the details just want to buy a good quality beginner telescope for visual observing, whether for yourself or as a gift, head to one of the links below. If you want to use your telescope for astrophotography, or you'd like to learn more about the different types of telescopes before making a buying decision, then continue reading below the line.

Best Telescopes for Beginners  |  Best Telescopes for Kids


Telescopes come in many shapes and sizes, and each type has their own strengths and weaknesses. The first step in deciding which telescope to buy is knowing what you want to use it for. Here are the ways to use a telescope:

  • Visual Astronomy — the process of looking through an eyepiece attached to a telescope to view distant objects
  • Astrophotography — the practice of using a camera attached to a telescope or lens to photograph objects in outer space
  • Both — If you want to use a telescope for both visual and imaging, that's okay too! Just know that telescopes that can do both well generally cost more. 

    For visual astronomy, especially beginner telescopes, most telescopes already come as a complete package. That means the telescope will be ready-to-use out of the box, and includes the telescope, the mount, and anything else you'll need to get started like eyepieces and other accessories. For doing astrophotography other than with a smartphone, the components are usually sold separately to allow for a more customized approach. This means that if you're interested in doing imaging beyond just with a smartphone, you'll likely need to buy the telescope, mount, and camera individually unless buying them together in a kit.

    A few popular beginner telescopes: Refractor, Schmidt-Cassegrain, and Dobsonian


    The second step in deciding which telescope to buy is having an idea of what you mainly want to observe or image. If you're able to narrow it down between one or the other, it will make your decision much easier. Of course, a telescope can be used for other purposes, such as terrestrial (daytime) viewing, but it's important to decide how you'll be using it at night first:

    • Planetary/Solar System Objects — this includes the planets, the Moon, and the Sun
    • Deep Sky Objects — this includes galaxies, nebulae, star clusters, and anything else beyond our solar system
    • Both Deep Sky & Planetary — there are a select group of telescopes that are great at both deep sky & planetary, especially for astrophotography, but they generally cost more

    The third and final step in deciding which telescope to buy is incorporating your budget, how portable of a setup you want, and your skill level into your decision. We've compiled this helpful chart of some of the most popular telescope types by their common use cases to help you:

      Visual Astronomy (with Alt-Az Mount)
    Astrophotography (with EQ Mount) Both Visual & Imaging (with EQ Mount)
    Beginner Refractor, Tabletop Dobsonian, or Binoculars
    Small Refractor or Camera Lens
    Small Refractor
    Widefield Small Refractor, Tabletop Dobsonian, or Binoculars
    Small Refractor, RASA, or Camera Lens
    Small Refractor
    Deep Sky Dobsonian, Refractor, SCT, or Newtonian Refractor, SCT, Newtonian, or RC
    Refractor, SCT, or Newtonian
    Planetary SCT, Mak-Cass, or Dobsonian SCT or Mak-Cass SCT or Mak-Cass
    Deep Sky & Planetary Dobsonian or SCT SCT with Reducer SCT with Reducer

     

      The above chart is meant to serve as a general guide to put you on the right track. It does not list every single type of telescope, just the most popular ones. If the names of these telescopes sound foreign to you, don't worry! In the next section, we'll go over our six most popular telescope types and explain their strengths and weaknesses. Although there are many types of telescopes out there, these six are the most common telescopes available.

      Refractor Telescopes


      Celestron StarSense Explorer LT80AZ

      Great for beginner visual observing and deep sky imaging for all skill levels

      Refractors are what you imagine of when you think of a telescope. They were the first telescope ever invented, and many beginners and advanced observers alike swear by refractors today. Though refractors have some competition for the best beginner visual telescope, they are widely regarded as the best beginner telescope if you're entering the hobby of deep sky astrophotography. Refractors are excellent for their portability, ease-of-use, and familiarity — refractors are very similar to camera lenses, which is a big plus for budding astrophotographers.

      For all of the great things they have going for them, quality refractors like apochromatic triplets are some of the most expensive telescopes per aperture. For that reason, a Dobsonian will usually outperform a refractor of the same price range visually, and a Schmidt-Cassegrain will outperform a refractor of the same price range for planetary viewing and imaging. All in all, though, refractors are some of the easiest and most versatile telescopes to use, and we highly recommend them especially for those looking to begin deep sky imaging.

      Explore Refractor Telescopes

      Schmidt-Cassegrain Telescopes


      Celestron NexStar 6SE Schmidt-Cassegrain Telescope

      The most versatile telescope type when paired with added extras

      Schmidt-Cassegrain Telescopes (SCTs) are wildly popular among both beginner and advanced amateurs alike for their versatility. Offering some of the longest focal lengths available in telescopes, SCTs are a fantastic choice for those looking to view — and especially to image — solar system objects like planets and the moon. The long focal length is a double-edged sword, though, as it can make locating objects in the night sky like trying to look at space through a straw. Many beginner SCTs (like the one above) come packaged with a motorized mount that can automatically point and track objects after a simple alignment process, which is basically a requirement to make sure you don't get lost in space looking for an object.

      SCTs are also arguably the most versatile telescope type available. Though their native focal length is very long, a variety of focal reducers made for SCTs can allow them to be used at medium and ultra-short focal lengths, which transform them into excellent performers for deep sky astrophotography. These focal reducers add a significant extra cost to SCTs, though, and will need to be paired with an equatorial mount for best imaging results. 

      Explore Schmidt-Cassegrain Telescopes

      Dobsonian Telescopes


      Sky-Watcher Flextube 250p Dobsonian Telescope

      Best bang-for-your-buck visual performer

      Many dedicated visual observers swear by the Dobsonian design because of its simplicity and pure light-gathering power. Although they are usually large, heavy, and all manual, Dobsonians can visually outperform other telescopes in the same price range because of their large aperture, which gathers more light. Although the telescope itself is technically a Newtonian and the term Dobsonian refers to the swivel-style mount, most amateur astronomers still know and refer to these telescopes as Dobsonians, or Dobs for short. These telescopes are an excellent choice for visually observing all kinds of celestial objects, but because of their large aperture, viewing faint deep sky objects is where Dobs really shine.

      Although Dobsonians are great visual performers, their simple altitude-azimuth mounts make them a poor choice for astrophotography, especially for deep sky imaging. Since they are technically Newtonian telescopes, Dobs will require frequent collimation, which is regular but easy maintenance similar to tuning an instrument before you play it. All things considered, if you're strictly looking to do visual observing and don't mind a heavy telescope, a Dobsonian gets our first pick.

      Explore Dobsonian Telescopes

      Newtonian Telescopes


      Celestron Astro Fi 130mm Newtonian Telescope

      Best for those who want a large aperture for both visual and imaging

      Newtonian telescopes are the classic reflector design. Instead of using lenses like refractors, Newtonians and other reflectors utilize mirrors to focus incoming light. Since lenses that are both large and high quality can get expensive fast, the Newtonian mirror design allows for a larger aperture — and therefore overall better light-gathering ability and detail — for a much more affordable price. In addition, reflectors like Newtonians don't suffer from color fringing on bright objects like some lower-end refractors do.

      Newtonians have their own issues to overcome, though, which are most present when doing astrophotography. Newtonians inherently have coma, which is an optical aberration in which stars appear elongated as you look farther away from the center. On some models, this is correctable with a coma corrector, which is highly recommended for imaging, but also adds extra cost. Newtonians also need to be collimated frequently, which is easy to do, but can increase the cost slightly for collimation tools. Last but not least, Newtonians are large and heavy telescopes and require an adequately heavy-duty mount to carry them, especially for astrophotography. Despite these drawbacks, Newtonians can still be one of the most affordable ways to get a large aperture telescope at a reasonable price.

      Explore Newtonian Telescopes

      Ritchey-Chretién Telescopes


      TPO 8" Carbon Fiber f/8 Ritchey-Chretién Telescope

      Best for long focal length deep sky astrophotography

      The Ritchey-Chretién (RC) design is one of the best optical performers available to consumers. Many professional astronomy telescopes, including the Hubble Space Telescope, utilize the RC design. Unlike their Newtonian cousins, RCs do not suffer from coma. RCs usually feature a long focal length, making them ideal for intermediate to advanced deep sky astrophotographers hoping to capture smaller targets like distant galaxies. They are also quite versatile, and can be used with focal reducers and extenders to alter the focal length, but not quite as much as SCTs. In addition to all of their benefits, entry-level RCs can actually be relatively affordable compared to other dedicated astrophotography telescopes.

      RCs do of course have their downsides. Unlike SCTs, for example, Ritchey-Chretiéns make for poor planetary imaging telescopes due to their large secondary mirror, which lowers contrast. This also limits their effectiveness as a visual telescope, so RCs are somewhat of a one-trick-pony for deep sky imaging. With their long focal lengths, Ritchey-Chretiéns are a great choice for intermediate to advanced astrophotographers that only want to focus on deep sky objects.

      Explore Ritchey-Chretién Telescopes

      Maksutov-Cassegrain Telescopes


      Meade ETX125 Maksutov-Cassgrain Telescope

      Best for affordable solar system/planetary viewing and imaging

      The Maksutov-Cassegrain, or Mak-Cass for short, is very similar to the Schmidt-Cassegrain design in that it uses a folded optics design to keep the overall size of the telescope more compact. Mak-Casses feature very long focal lengths for their size, which make them very well-suited to planetary viewing and imaging out of the box without the need for extras like Barlow lenses. As an added plus, Mak-Casses are very affordable and portable, making them great grab-and-go planetary telescopes for beginners.

      For those looking at buying a Mak-Cass, they are often compared to SCTs which are similar. Mak-Casses will take a longer time to adjust to air temperature outside than an SCT will. And while SCTs are usually set around f/10, Mak-Casses are generally around f/12 to f/15. This makes them a poor choice for imaging deep sky objects due to longer exposure times. Unlike SCTs, Mak-Casses are much less compatible with focal reducers, which make them much less versatile overall. However, they are generally great optical performers at their native focal ratio.

      Explore Maksutov-Cassegrain Telescopes

      FAQs

      Still have questions? We have answers.

      What can I see with a telescope?
      It depends on the telescope. Each telescope will give a different view, depending on their focal length and aperture. However, most telescopes, even many beginner telescopes, can see craters on the moon, Jupiter's four main moons, Saturn's rings, and possibly some brighter deep sky objects like the Pleiades Star Cluster.

      Away from city lights, more faint deep sky objects become visible. This includes the Andromeda Galaxy, the Orion Nebula, and many other objects. To find out what's in the sky tonight and the coming weeks, head to EarthSky.org for reference. Telescopes with larger apertures (front openings) will give better and more detailed views.

      With larger aperture telescopes of around 8" (200mm) and up, even more details can be revealed. You can begin to see details like the Great Red Spot on Jupiter with the right eyepiece. With even larger telescopes, the sky is the limit — literally!

      What are the three main types of telescopes?
      The three main types of telescopes are:

      - Refractors: use lenses to focus incoming light
      - Reflectors: use mirrors to focus incoming light
      - Catadioptrics: use a combination of lenses and mirrors to focus light

      All optical telescopes fall under one of these three categories, and each have their strengths and weaknesses. To learn about each type in more detail and understand the pros and cons of each, head to our blog post about The Basic Telescope Types.

      How does a telescope work?
      A telescope gathers large amount of incoming light through an opening at the front called the aperture. It then uses lenses, mirrors, or both in combination to magnify and focus that light, which gets projected out of the telescope to an eyepiece or camera. You can read more (and watch a helpful video) on how a telescope works here.

      What telescope is best for visual astronomy?
      There are many telescopes that are great for visual astronomy. If you're a beginner just starting out on a limited budget under $250, check out our bestselling visual telescopes. If you have a little more budget to spend between $250-$500, you can get a larger aperture telescope including some full-size Dobsonians. Above $500, you can choose from many telescopes with go-to capability, which automatically point to and track objects. For visual astronomy, we recommend buying the largest aperture telescope you can both carry and afford.

      Which telescope is best for deep sky astrophotography?
      While many telescopes are great for visual astronomy, a much smaller percentage of telescopes are great for deep sky astrophotography. Here are some general features to look for in telescopes for deep sky astrophotography, regardless of telescope type:

      - Fast focal ratio of around f/7 or lower (or attainable with a reducer)
      - An image circle large enough for your camera's sensor (or attainable with a reducer)
      - The telescope weighs less than half of your equatorial mount's payload capacity
      - A quality equatorial mount is just as important as the telescope for deep sky imaging

      Which telescope is best for planetary astrophotography?
      While it's true you can take photos of the planets with just a smartphone, you can get even better results with the right telescope and a planetary imaging camera. Here's what to look for in a telescope for planetary imaging:

      - Long focal length, ideally 2000mm or longer
      - The largest aperture telescope you can afford, ideally 7" or larger
      - Preferably a SCT or Maksutov-Cassegrain optical design

      Which telescope has the best resolution?
      Generally speaking, telescopes with larger apertures than others will have better resolution. This also depends on the optical design, but large aperture telescopes can resolve more detail than those with smaller apertures.

      Is it safe to look at the sun through a telescope?
      Never look at the sun without the proper filters, especially through a telescope! Since telescopes gather much more light than the human eye, looking at the sun without proper equipment can cause serious injury or even blindness. Before you even point your telescope at the sun, you need to attach a solar filter based on your telescope's size.

      There are also dedicated solar telescopes that are designed to only observe the sun with h-alpha filters. These telescopes will provide even better views and images than a normal (white light) solar filter. Click here to shop dedicated solar telescopes.

      Can a telescope see flags the Apollo astronauts left on the moon?
      We wish! Not even the Hubble Space Telescope can see the flags left on the moon. You can, however, locate the approximate location of the Apollo landing sites with most telescopes and a lunar map.

      Glossary

      In this section, we’ll go over some common manufacturer’s specs and define them in layman’s terms, so you can know what each specification means when buying a telescope.

      Optical Design
      This is the optical design of the telescope, i.e. APO Triplet Refractor. You can reference almost all popular consumer optical designs and their pros and cons above.

      Aperture
      Aperture is the diameter of the front opening of the telescope. It’s the most important indicator of a telescope’s performance. The larger the aperture, the more details a telescope will be able to resolve. Aperture is usually measured in either inches or millimeters (mm).

      Focal Length
      Like in a camera lens, focal length is the measurement of how far the light travels once it enters the main optic of a telescope until it reaches the point of focus. This measurement is half of what determines how zoomed in the view or image will be, with the eyepiece or the camera being the other half. Focal length is usually measured in millimeters (mm). Generally speaking, a telescope with a focal length under 500mm is considered short, 500-1000mm is considered medium, 1000-2000mm is considered long, and 2000mm and up is considered very long. For beginner astrophotographers, a short to medium focal length telescope is recommended to begin.

      Focal Ratio (F/Ratio)
      Focal ratio is a measurement used to determine how fast a telescope gathers light. It’s a simple formula that takes the focal length divided by the aperture. For example, if a telescope has a focal length of 480mm and an aperture of 80mm, it would have a focal ratio of f/6. Fast scopes (usually f/7 or lower) gather light quicker, but usually lack the long focal lengths used to get zoomed in views. Fast, shorter focal length scopes are best suited for deep sky object viewing and imaging. Slow scopes (usually f/8 or higher) gather light slower and are generally more zoomed in, but usually lack the light-gathering power to reveal faint details for deep sky astrophotography. Slower, longer focal length scopes are best suited for planetary/lunar viewing and imaging.

      OTA
      OTA stands for Optical Tube Assembly. In today's terms, this phrase is simply a fancy way of referring to a telescope on its own. When you see a telescope with "OTA" or "OTA only" in its description, that means that the product only includes the telescope and not a mount or other components.

      Optical Tube/OTA Weight
      This is the total weight of the telescope only, usually not including accessories like a finder scope or something else unless otherwise specified. This is an important number to pay attention to if you’re buying a telescope and mount separately, as many mounts have a maximum payload (weight) capacity that they can handle. For visual use, the OTA Weight can be a few pounds/kg below the payload capacity of a mount. For deep sky astrophotography, though, a highly recommended rule of thumb is that you keep the OTA Weight around half of the total payload capacity for the mount. This is because deep sky astrophotography requires a much higher degree of accuracy than visual observing, and mounts perform at their best with lighter payloads.

      Finder Scope
      This is a small telescope or red-dot finder that rides on top of the main telescope. When looking for an object through a longer focal length telescope, it can be easy to get disoriented in space quickly. A finder scope’s purpose is to help you find objects using a much wider field of view. Once you’ve centered the object in your finder scope, the object should be readily visible in the main telescope.

      Diagonal
      A diagonal, or star diagonal, refers to the right angle part found in most refractor and catadioptric telescopes that reflects light out the back of the telescope and up into the eyepiece.

      Highest Useful Magnification
      This figure describes the most magnification you’ll want to use visually with the telescope in reference and any given eyepiece. Since the Earth’s atmosphere blurs and distorts the view for all ground-based telescopes, you won’t want to expect better than this magnification rate. A general rule of thumb is that the highest useful magnification is 50x its aperture in inches, or 2x its aperture in millimeters.