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Explore Scientific 8-inch Dobsonian Reflector Telescope (Red)

SKU ES-ON20859RR
Original price $699.99 USD - Original price $699.99 USD
Original price
$699.99 USD
$699.99 USD - $699.99 USD
Current price $699.99 USD
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  • 208mm (8-inch) Primary Mirror
  • 1219mm Focal Length
  • f/5.9 Focal Ratio
  • Dobsonian-style Mount
  • 2-inch Crayford Focuser with 1.25-inch Adapter
  • Optical Tube Weight: 19 lbs 15.6 oz
  • Base Weight: 18 lbs 11 oz
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  • Description
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  • Explore Scientific 8-inch Dobsonian Reflector Telescope (Red)

    The Explore Scientific 8-inch Dobsonian Reflector Telescope combines a 208mm paraboloid primary mirror with a 1219mm focal length (f/5.9) on a Dobsonian base with a spring tension system. The optical tube weighs 19 lbs 15.6 oz and the base 18 lbs 11 oz, and the two separate for carrying.

    208mm f/5.9 Paraboloid Optics: Light Gathering for Deep Sky and Planets

    The 208mm primary mirror is the heart of this telescope, and the Classic Dobsonians drink in light to reveal lunar and planetary detail and reach farther into deep sky for dimmer nebulae, galaxies and star clusters. The 46mm secondary mirror gives a central obstruction of 22.1% by diameter.

    The primary mirror has a paraboloid figure, which avoids the spherical aberration of a spherical mirror, and a coating of 90% reflectivity with an SiO2 overcoat. The Classic Dobsonians are astronomy workhorses.

    Two-Piece Portability: A 19 lb 15.6 oz Tube and 18 lb 11 oz Base

    Designed for easy transport and setup, this Dobsonian breaks down into two manageable components: the 19 lbs 15.6 oz optical tube assembly (OTA) and the 18 lbs 11 oz wooden base. To separate them, unhook the springs from the spring posts on the base; the springs stay on the tube's altitude bearings so they are not lost.

    The Dobsonian base provides smooth, intuitive "push-to" motion in both altitude (up-down) and azimuth (left-right). Explore Scientific's spring tension system maintains tube balance and accommodates optional accessories, and the manual says the tube moves smoothly and stays in place when released. The base needs no polar alignment. Once assembled, it does not need to be taken apart except for shipping or long-term storage.

    2-inch Crayford Focuser, Eyepieces and Barlow

    The 2-inch Crayford focuser has a focus lock thumbscrew and a 1.25-inch adapter, so it takes both 2-inch and 1.25-inch eyepieces.

    The included accessory package covers a wide range of magnifications. You get a 2-inch 25mm 70-degree Series wide-angle eyepiece for low-power views at 49x and a 1.25-inch 10mm Plossl for 122x. The included 2x Barlow doubles the magnification of the 1.25-inch eyepieces, so the 10mm gives about 244x on nights of steady air. A smartphone adapter is included to aid in simple astrophotography, and a dust cover helps keep dust off the mirrors in transit and storage.

    Red-Dot Finder Alignment and Collimation

    The telescope tube comes fully assembled, and it includes a red-dot finder, which projects an illuminated dot onto a non-magnifying window, showing you exactly where the telescope is pointing. To align it, center a distant object in the 25mm eyepiece, place the red dot on the same object with the finder's adjustments, and check on a second object. It stays aligned unless bumped or removed.

    Like all Newtonian reflectors, the mirrors require occasional alignment, or collimation. The optics were collimated in the factory, but transport can shift them. The secondary mirror tilts with three collimation screws, and the primary mirror has spring-loaded collimation knobs with locking thumbscrews. The manual walks through the three steps, and close enough is good enough while you learn.

    Beyond the Moon: What a 208mm Aperture Reveals in Deep Sky

    With its 208mm aperture, this telescope is a capable deep-sky instrument. From a dark site it can show hints of spiral structure in the Whirlpool Galaxy (M51), a dust lane in the Andromeda Galaxy (M31), and resolve the outer stars of bright globular clusters such as the Hercules Cluster (M13).

    Closer to home, the views are equally impressive. On the Moon you will see craters, mountains and rilles. Saturn's rings show the Cassini Division on steady nights, and Jupiter shows its cloud bands and four Galilean moons.

  • What can I see with the Explore Scientific 8-inch Dobsonian?

    With its 208mm aperture you can expect to see the rings of Saturn, the cloud bands and Great Red Spot on Jupiter, the phases of Venus, and countless craters on the Moon. For deep-sky objects, it will show you bright globular clusters like M13, nebulae like the Orion Nebula (M42), and dozens of galaxies from a dark site.

    How does the 8-inch Dobsonian perform on Jupiter and Saturn?

    Using the included 10mm eyepiece and 2x Barlow lens for about 244x, you can see the Cassini Division in Saturn's rings on a night of good atmospheric seeing. On Jupiter, you will be able to track the Galilean moons and see its main belts and zones.

    Is the Explore Scientific 8-inch Dobsonian portable enough for dark sky sites?

    It breaks down into two parts, the 19 lbs 15.6 oz optical tube and the 18 lbs 11 oz base, each carried separately. The 1156mm (45.5-inch) tube length is the size to check against your vehicle.

    What is the highest useful magnification for this 8-inch Dobsonian?

    The rule of thumb is 2 times the aperture in millimeters, 416x for this telescope, though typical skies will not allow it. The included 10mm eyepiece with the 2x Barlow gives about 244x, for nights of steady air.

    Can I use 2-inch eyepieces with this Explore Scientific telescope?

    Yes. The 2-inch Crayford focuser takes 2-inch eyepieces, and the included 25mm 70-degree eyepiece is one. A 1.25-inch adapter is included for the 10mm Plossl and the Barlow.

    How would this 8-inch Dobsonian handle a large target like the Andromeda Galaxy (M31)?

    With the included 25mm 70-degree eyepiece at 49x, the true field is about 1.4 degrees (70 / 49), which frames the bright core and inner disk with M32 and M110 nearby. From a dark site a dust lane may show.

    What is collimation and how often will I need to do it with this 8-inch Dobsonian?

    Collimation is the process of aligning the telescope's mirrors. For a Newtonian telescope like this one, it's a normal part of maintenance. Rough handling knocks it out of collimation, so treat the telescope gently. Check it after transport; the manual walks through the steps.

    Is the Explore Scientific 8-inch Dobsonian a good telescope for a beginner?

    The Dobsonian mount is easy for astronomers of all skill levels to operate, and the accessories in the box (two eyepieces, a Barlow, a red-dot finder and a smartphone adapter) let you start observing right away.

    Can I do astrophotography with the Explore Scientific 8-inch Dobsonian?

    This telescope is designed primarily for visual observation. The manual Dobsonian mount does not track the stars, which is required for long-exposure photography of deep-sky objects. Explore Scientific includes a smartphone adapter to aid in simple astrophotography, such as short phone images of the Moon and bright planets.

    Why should I start observing with the 25mm eyepiece instead of the 10mm?

    Starting with the lower-power 25mm eyepiece (49x) gives you a much wider field of view. This makes it significantly easier to find and center your target. Once you have an object centered, you can then switch to the higher-power 10mm eyepiece (122x) to see more detail, without the frustration of trying to locate it in a narrow field of view.

  • Primary Mirror Diameter 208mm
    Focal Length 1219mm
    Focal Ratio f/5.9
    Mount Type Dobsonian
    Optical Tube Weight 19 lbs 15.6 oz
    Base Weight 18 lbs 11 oz
    Aperture 208mm
    Focuser / drawtube size 2" Crayford with 1.25" adapter
    Central obstruction 22.1% (46 mm secondary)
    Tube length (retracted) 1156 mm (45.5 in)
    Tube outer diameter 254 mm (10 in)
    Optical Design Newtonian reflector
    • 70-degree Series 25mm eyepiece (49x)

      × 1

    • 10mm Plossl eyepiece (122x)

      × 1

    • 2x Barlow lens

      × 1

    • 2-inch Crayford focuser with 1.25-inch adapter

      × 1

    • Red-dot finder

      × 1

    • Smartphone adapter

      × 1

    • Dust cover

      × 1

  • Explore Scientific Warranty