$491.94. Available in 10, 12, & 16-inch apertures, this open truss design allows for increased portability over standard solid-tube designs and is able to provide easy setup and teardown for a large aperture telescope. With focal ratios of less than F/4, this line of Truss-Dobsonians allows the unique observing experience of large apertures without a ladder for many observers. Large Aperture. Dobsonian telescopes are good for deep-sky objects, including galaxies, nebulae and dim star clusters. If purchased separately. These diameters are extremely large, especially compared to standard telescopes that are outfitted for general viewing. A Dobsonian telescope is an altazimuth-mounted Newtonian telescope design popularized by John Dobson in 1965 and credited with vastly increasing the size of telescopes available to amateur astronomers.Dobson's telescopes featured a simplified mechanical design that was easy to manufacture from readily available components to create a large, portable, low-cost telescope. That is what makes Dobsonians so unique is the diameter of the apertures that they can support. This 12-inch Dobsonian telescope features a twelve-inch aperture that is large enough to collect enough light from the sky to provide you with a beautiful, clear, and perfectly crisp view of the celestial objects. Additional Eyepieces. Twelve Inch Aperture. Anyone can engage in deep-space observation in their own backyard with a Dobsonian. It has a large aperture, the stable base glides easily to give you total pointing control, and this package includes a Barlow and Beginning Stargazer's Toolkit. The 8” represents the diameter of the primary mirror which is 203 mm. You will be able to see a close-up of the Moon and the planetary system. 3 easy payments of $146.66 With payment plan. The redesigned Dobsonian base has a no-tool assembly and provides improved stability. Additionally, as mentioned, Dobsonian telescopes are good for beginners and all sorts of amateur astronomers due to their portability, affordability and ease-of-use. $439.99 . Large apertures, very fast focal ratios and best of all, SHORT eyepiece heights! Dobs are known for their large apertures and they’re often cheaper in price against telescopes with the same measuring diameter. Combining these superb optics with a large Dobsonian aperture helps ensure you’ll have bright, bold views of faint deep sky objects. It’s a decent size for a Dob and offers excellent handleability for the beginner. To ensure Sky-Watcher Dobsonians remain easy to use, all Collapsible Dobsonians include a mount base that is so smooth, it can be rotated with the push of a finger. The sizes of the primary apertures on a Dobsonian telescope usually start at 6” and scale all the way up to 10” or even 12”.