Sky-Watcher Virtuoso GTi 150P GoTo Tabletop Dobsonian Telescope
- 5.9" / 150mm Aperture
- f/5 Focal Ratio, 750mm Focal Length
- 25mm & 10mm Super Eyepieces
- SynScan GoTo App for iOS and Android
Celestron StarSense Explorer DX 130AZ 130mm f/5 AZ Reflector Telescope
- Use Smartphone App for Star Navigation
- Follow Directions to Find Great Objects
- Advanced Precise Alignment Algorithm
- Oversized 130mm Reflector Optical Tube
Sky-Watcher Heritage 150 150mm f/5 Tabletop Reflector AZ Telescope
- 150mm Dobsonian Reflector OTA
- 750mm Focal Length, f/5 Focal Ratio
- Collapsible Design: Just 16.75" Closed
- Aluminum-Coated Parabolic Mirrors
Sky-Watcher Heritage 130mm f/5 Tabletop Reflector Telescope
- International Year of Astronomy Edition
- 130mm Dobsonian Reflector OTA
- 650mm Focal Length, f/5 Focal Ratio
- Collapsible Design: Just 14.5" Closed
Celestron FirstScope 76mm f/4 Signature Series Moon Alt-Az Reflector Telescope
- Graphic of the Moon on Tube
- 76mm Aperture Newtonian Reflector
- 300mm Focal Length, f/4 Focal Ratio
- 1.25" Rack-and-Pinion Focuser
Celestron AstroMaster 114EQ 114mm f/8.8 Reflector Telescope
- 114mm Newtonian Reflector OTA
- 1000mm Focal Length, f/9 Focal Ratio
- CG-2 Manual German Equatorial Mount
- RA and Dec Slow Motion Cables
Sky-Watcher 6" Traditional Dobsonian Telescope Kit
- Bright 152mm Aperture
- 1200mm Focal Length, f/7.9 Focal Ratio
- Highly Reflective Borosilicate Mirror
- 2" R&P Focuser with 1.25" Adapter
Celestron PowerSeeker 127EQ 127mm f/8 Reflector Telescope with Accessory Kit
- 127mm Newtonian Reflector OTA
- 1000mm Focal Length, f/7.87 Focal Ratio
- Multi-Coated Primary Parabolic Mirror
- Manual German Equatorial Mount
Celestron StarSense Explorer 114mm f/4 Tabletop Dobsonian Telescope
- Use Smartphone for Tour of Night Sky
- See Moon, Planets, Nebulae, Galaxies
- 114mm / 4.5" Parabolic Mirror
- 17mm & 10mm Eyepieces
Celestron StarSense Explorer 130mm f/5 Tabletop Dobsonian Telescope
- Use Smartphone for Tour of Night Sky
- See Moon, Planets, Nebulae, Galaxies
- 130mm / 5.1" Parabolic Mirror
- 25mm & 10mm Eyepieces
Celestron StarSense Explorer LT 114AZ 114mm f/9 AZ Reflector Telescope
- Use Smartphone App for Star Navigation
- Follow Directions to Find Great Objects
- Advanced Precise Alignment Algorithm
- Powerful 114mm Reflector Optical Tube
Celestron FirstScope 76mm f/4 Signature Series Moon Alt-Az Reflector Telescope with Map Kit
- Graphic of the Moon on Tube
- 76mm Aperture Newtonian Reflector
- 300mm Focal Length, f/4 Focal Ratio
- 1.25" Rack-and-Pinion Focuser
Celestron PowerSeeker 127EQ 127mm f/8 Reflector Telescope
- 127mm Newtonian Reflector OTA
- 1000mm Focal Length, f/7.87 Focal Ratio
- Multicoated Primary Parabolic Mirror
- Manual German Equatorial Mount
Celestron StarSense Explorer 12" f/4.9 Dobsonian Telescope
- StarSense Scans Sky, Lists Objects
- Follow On-Screen Arrows to Targets
- 12" Newtonian Reflector Optical Tube
- Large Aperture for Impressive Detail
Celestron Advanced VX 8 200mm f/5 GoTo Reflector Telescope
- 200mm Aperture
- 1000mm Focal Length, f/5 Focal Ratio
- Anti-Reflection Fully Coated Optics
- Rack-and-Pinion Focuser
Vixen Optics R200SS 200mm f/4 Reflector Telescope (OTA Only)
- 200mm (8") Newtonian Reflector OTA
- 800mm Focal Length, f/4 Focal Ratio
- Anti-Reflection Multi-Coated Optics
- Rack-and-Pinion Focuser
Unistellar eVscope 2 114mm f/4 GoTo Reflector Telescope
- Digital Eyepiece for Visual Observations
- Streams Views to 10 Phones and Tablets
- Onboard Image Processing Computer
- Autonomous Field Detection Alignment
Polaroid 76700 60mm f/9 Reflector Telescope
- 60mm Reflector-Style OTA
- 700mm Focal Length, f/9 Focal Ratio
- Manual Alt-Azimuth Mount
- 0.965" Rack-and-Pinion Focuser
Explore Scientific National Geographic 76mm Compact Reflector Telescope
- Tabletop Dobsonian-Style Reflector
- Fully Assembled & Ready to Use
- 6mm and 20mm Eyepieces
- 2x Barlow Lens
Carson JC-200 76mm f/3.9 SkySeeker Reflector Telescope
- 76mm Aperture SkySeeker Telescope
- 300mm Focal Length, f/3.9 Focal Ratio
- Manual Tabletop Alt-Az Mount
- 15 and 37.5x Magnification
ExploreOne Aurora II 114mm f/4 AZ Telescope (Flat Black)
- 114mm Newtonian Reflector
- 500mm Focal Length, f/4 Focal Length
- 9.7mm and 26mm Eyepieces
- 1.25" Rack-and-Pinion Focuser
Barska Starwatcher 525 Power Telescope
- 76mm Aperture
- 525.0x Magnification
- 700mm Focal Length
- Red Dot Finderscope
Explore Scientific National Geographic NT114CF 114mm f/4.4 Reflector Telescope (Silver)
- 114mm Newtonian Reflector OTA
- 500mm Focal Length, f/4.4 Focal Ratio
- 26 & 9.7mm Eyepieces & 2x Barlow Lens
- Manual Alt-Az Mount
Carson RedPlanet 35-88 x 76mm Newtonian Reflector Telescope
- 2.99" / 76mm Newtonian Reflector
- Focal Length: 700mm
- Two 1.25" Erecting Eyepieces
Carson RP-100SP RedPlanet 76mm f/9 Reflector AZ Telescope
- 76mm Newtonian Reflector OTA
- 700mm Focal Length, f/9 Focal Ratio
- Manual Alt-Azimuth Yoke Mount
- 8mm and 20mm Erect-Image Eyepieces
Explore Scientific National Geographic StarApp114 114mm Reflector Telescope
- 114mm Newtonian Reflector OTA
- 500mm Focal Length, f/4.4 Focal Ratio
- 26 & 9.7mm Eyepieces, 2x Barlow Lens
- Smartphone Mount for ARTelescope App
Celestron PowerSeeker 114EQ 114mm f/8 Reflector Telescope
- 114mm Newtonian Reflector OTA
- 900mm Focal Length, f/8 Focal Ratio
- Multi-Coated Primary Parabolic Mirror
- Manual German Equatorial Mount
Celestron ExploraScope 114AZ 4.5" f/8.8 Alt-Az Reflector Telescope
- Aperture: 114mm / 4.5"
- Focal Length: 1000mm, f/8.8 Focal Ratio
- Anti-Reflection Fully Coated Optics
- 1.25" Rack-and-Pinion Focuser
Learning About Newtonian Reflectors
Newtonian reflectors are a popular choice in astronomical telescopes that use curved mirrors to reflect light onto smaller angled mirrors and into side-mounted eyepieces. Newton developed this telescope to overcome chromatic aberration problems with the lenses used in early refractor telescopes. You can use this simple, yet effective design with a large aperture that's ideal for looking at faint objects in the sky.
What Are Newtonian Reflectors?
Newton telescopes, such as Bushnell reflector telescopes, have a cylindrical shape that's open at the top. A large diameter parabolic primary mirror is at the bottom, and a small flat mirror sits at 45 degrees near the top of the tube. This second mirror reflects light onto an eyepiece mounted on the side of the telescope. Some reflector telescopes have coma corrector lenses to reduce aberrations at the edge of your viewing field. Because the eyepiece is on the side of the telescope, viewing is more comfortable than with comparable lens-based refractor telescopes.
The focal length of the primary mirror in a Newtonian telescope determines its overall length. Compound telescopes, also known as catadioptric (Cassegrain) telescopes, use a combination of two curved mirrors and an end-mounted eyepiece that reduces the overall length of the telescope, while permitting an increase in focal length.
Dobsonian Telescopes
Dobsonian telescopes, such as Tasco reflector telescopes, are Newtonian reflector telescopes mounted on an altazimuth mount. This type of mount has two degrees of movement, one vertical and the other horizontal, and is similar in concept to a photographic tripod. Although the original Dobsonian telescope concept was that it was lighter than comparative Newtonian telescopes, the main attribute of current Dobsonian telescope kits is a mount that's simple and easy to use.
Celestial Tracking Capabilities
While an altazimuth mount is easy to use, it doesn't follow the path taken by stars, so constant horizontal and vertical adjustments are necessary when tracking celestial bodies. An equatorial mount overcomes this problem by tilting the angle of rotation to match the earth's axis of rotation. This satisfies any astrophotographer's need for a long-time exposure. However, you can overcome the disadvantages of the altazimuth mount by using GoTo Dobsonians. These are Dobsonian telescopes with digital axis control that automatically tracks the movement of the stars.
Telescope Aperture and Magnification
A telescope's aperture is the diameter of its primary mirror. Larger mirrors collect more light and are brighter and sharper. The focal ratio is the focal length of the lens divided by its aperture, and as with camera lenses, smaller values are brighter. Determine magnification by dividing the focal length of the lens by the focal length of the telescope eyepiece. As a rule of thumb, it's best to avoid magnifications greater than 50 times per inch of aperture. If you're an amateur photographer, you may want to use a lower magnification, especially when using solar telescopes to view large objects like the sun or moon.
You can find the best Newtonian reflector telescope for your celestial viewing at B&H Photo and Video.