Explore Scientific Generation II - 20" Truss Tube
"NOTE: CUSTOM ORDER - Average 90-day wait time."
- Fast, Truss Tube Dobsonian Telescope
- 20", f/3.6 Quartz Primary parabolic Mirror
- Easy Assembly, easy to transport
- 1,826 mm focal length
- Max. magnification = 1,000x approx.
- Includes fans and battery pack to cool mirror
- All TIG welding construction for stiffness
- Light weight for its size
- 6 Support feet under rocker box for stability
This Explore Scientific Generation II - 20" Truss Tube Dobsonian Telescope is an ideal workhorse for deep sky astronomy observers. The Explore Scientific 20-inch f/3.6 Truss-Tube Dobsonian is their largest aperture telescope. The 500 mm (20" diameter) mirror collects 5,100 times more light than the naked eye! This large aperture will provide images of celestial objects for your pleasure which you have not imagined before. Details on planets and deep sky objects will be visible even for inexperienced observers. Bright star clusters are resolved to the core, and the sight of the terminator on the moon will always be an unforgettable experience. The brightness of images for all objects, especially planets and nebulae will amaze you. If you have not viewed with a 20" aperture telescope before, you are in for a truly delightful and pleasant experience.
The fast 20" f3.6 main mirror as well as the large 120 mm secondary mirror are made of high quality quartz, so the cooling time is reduced to a minimum and this Dobsonian telescope will be quickly ready for use, with no long wait time. Every main mirror is delivered with an individual optical test certificate, which guarantees the highest optical quality performance, as you would expect for a large telescope from Explore Scientific. A laser engraved center mark of the main mirror allows easy adjustment. The optical surface has a high-quality aluminum coating with 94% reflectivity and an extremely resistant quartz protection layer. Multiple fans are included in the Mirror Box assembly to cool the optics and to help reduce any fogging due to humid air conditions. The mirror overcomes frequently occurring dew fogging and cleanups without damage and guarantees a long service life.
The ingenious combination of simple yet effective mechanisms with the greatest possible aperture gives the Dobsonian telescope a unique set of characteristics which make it so popular with astronomers. Disassembly of the scope without using tools ensures a trouble-free transport of this great scope even in small cars. The entire structure has been optimized for maximum stiffness with minimal weight. The combination of large, strong altitude bearings with optimized aluminum structures allows fine adjustment and hand tracking, even at high magnifications.
All connections of the tube structure were made using a professional TIG welding process and no rivets and screws were used. This has made it possible to produce this 20" light weight Dobsonian so unbelievably stiff in spite of the low weight - a noticeably good quality which you will appreciate each time you use this Explore Scientific Generation II - 20" Truss Tube Dobsonian Telescope. The production of almost all mechanical components is carried out by manufacturing partners in Hungary and the final assembly of the optics and subsequent quality control takes place in Rhede, Germany.
A second 40° displaced installed mounting plate with a viewfinder shoe allows the rotation of the tube top in combination for a favorable position of the viewfinder, or the mounting of an additional viewfinder. The 6 supporting feet underneath the rocker box offers perfect stability and guarantees smooth tracking in azimuth. Four smaller fans are installed in the side of the mirror box as well as a large fan installed under the main mirror. This allows an even quicker adaptation to the ambient temperature and reduces the tube seeing (by providing the boundary layer removal). The lateral altitude wheels can now be stowed comfortably in the foam layers of the mirror box, when disassembling this telescope for transport.
This Generation II - 20" Truss Tube Dobsonian Telescope from Explore Scientific also includes a 2.5" HEX focuser with helical gearing and 10:1 focus control reduction; a Finder; a collimation assist tool; soft light baffle; two radial main mirror fans (fast temperature equilibrium); battery holder; and counterweights to install on truss poles as needed to achieve optimum balance. The telescope is also ready to be used with an optional purchase coma corrector sold by Explore Scientific.
|Focal length:||1,826 mm|
|Primary mirror diameter:||50 cm (20 inches)|
|Mirror cell support points:||18|
|Truss pole length:||100 cm|
|Truss pole diameter:||25 mm|
|Secondary cage diameter:||57 cm|
|Secondary cage assy. weight:||8 pounds|
|Secondary cage assy. height:||95 cm|
|Mirror box/rocker box height:||56 cm|
|Mirror box weight:||105 pounds, approx.|
|Height to eyepiece at zenith:||170 cm|
|Rayleigh limit resolution:||0.23 arc sec|
|Limiting magnitude:||16.19 mag|
|Includes:||2.5" HEX focuser, helical gearing, 10:1|
|Includes:||a Finder; collimation assist tool;|
|Includes:||Soft Light Baffle Plate|
|Includes:||2 radial main mirror fans|
|Includes:||Battery Holder kit|
|Includes:||Counterweights for truss poles as needed|
|Note:||Mirror weight values are approximate|