Why we Love Dobsonian Telescopes
Dobs are one of the best options for beginners who want to learn the sky without a computerized mount. Also known and light-buckets, these can open the universe to you. The human eye is capable of seeing 10,000 stars. A 10-inch Dobsonian telescope can show you 50,000,000! These are great tools for exploring the universe
At their heart, these are Newtonian telescopes on a simple altazimuth mount. They were popularized in the 1960's by John Dobson. Dobsonians vastly improved the aperture/dollar ratio and made large aperture (relatively) inexpensive for amateur astronomers.
Because the mounts are so simple, these instruments are economical, and allow you to manually find and track celestial objects. They're a great way to learn how to star-hop and find your way between constellations, asterisms and other things to see in the sky.
What to See With a Dobsonian Telescope
Dobs have huge primary mirrors paired with medium focal lengths. This makes it easy to get extraordinary views of our solar system. You'll see incredible detail on the moon, and planets. The Cassini division in the rings of Saturn will be visible, along with the bands of Jupiter and the Galilean moons.
These telescopes are ideal for visually observing faint deep-sky objects like nebulae and galaxies because they take in so much light. Taking in wide field views of the Milky Way is a real treat as well. The Dobsonians we have come with focusers that will accept 2" and 1.25" eyepieces offering a wide variety of magnifications and fields of view.
Advantage of Using a Dobsonian Telescope
Dobs are designed to be easy to use, reliable, and to gather as much light as possible. This means that there's a great 'wow' factor with a dob, and they won't break the bank. They're also easy to set up.
We don't recommend Dobsonian telescopes for deep sky astrophotography because of their inability to smoothly track for long exposures. They do well with lunar and planetary astrophotography though.
Collimating a Newtonian Telescope
Collimating is the process of aligning the optics in a telescope. There are a few ways to tell whether a dobsonian needs collimation, but the easiest way to check is to find a bright star, defocus the telescope and look at the rings around the bright spot. If they're concentric (evenly spaced around the bring spot) the dob is well collimated.
There's all kinds of information online about frequency of collimation, with answers ranging from every time you use the dob to once a year. The reality is that it needs to be done when it goes out of alignment which will be a function of how much it get's moved around and what kind of forces its subjected to.
Collimating a dob means aligning the primary mirror and the secondary mirror. We have a great video on laser collimation (it's easier than it sounds).
Popular Sizes of Dobsonian Telescope
We have 12 inch, 10 inch, 8 inch, and 6 inch Dobs with flex tube, go-to, and solid tube options. We have some table-top Dobs as well, which work well in library programs and for kids.
8 Inch Dobs
8-inch dobsonian telescopes are one of the most recommended beginner telescopes around. There are several reasons for this, but the most important is that an 8 inch is big enough to start showing detail in deep sky objects. That means seeing nebulosity, and seeing spiral structure in something like the andromeda galaxy. Our favourite 8" dobs are the Sky-Watcher Classic 200p 8" Dobsonian Telescope and the Celestron StarSense Explorer Smartphone App Enabled 8" Dobsonian Telescope.
10 Inch Dobs
10-inch dobsonian telescopes are our second most popular size, and a shop favourite. A 10-inch dob can show you 50,000,000 stars! They gather 44% more light than the 8-inch dobs, which translates to brighter, more detailed images. That's particularly true when looking at deep sky objects like nebulae and galaxies. Our favourite 10" dobs are the Sky-Watcher Classic 250p 10" Dobsonian Telescope and the Celestron StarSense Explorer Smartphone App Enabled 10" Dobsonian Telescope.
Different Dobsonian Options
Solid tube versions will need less frequent collimation, and they can be used for solar viewing with the right filter. Flex tube, or truss tube or collapsible dobs are nice because of the increased portability that you get from them. The trade off's are that they're not suitable for solar viewing, and they'll need more frequent collimation.
A goto dob is simply a computerized alt azimuth base to have it find and track different celestial objects. You can find goto bases with solid or flex tube designs.
What Should you Buy With a Dobsonian Telescope
Astronomy is a hobby full of marginal gains, and there are all kinds of accessories that will help you to get the most out of your dob. There are all kinds of eyepieces that will help you to get the right magnification and field of view for objects. There are also star charts and books that can help you to navigate the sky. We recommend everyone get a laser collimator and a lens pen to maintain their dob.
