Astronomy Professional Telescope 20 Inch Very Very Large Telescope Astronomy
SPECIFICATIONS
Brand Name: NONE
Focuser mechanism: 1.25 inch crayford
High-concerned chemical: None
Maximum practical power: 1000 x
Objective diameter: 20 " (508mm)
Origin: Mainland China
Product Type: Wood DIY Package
Shipping Weight: 138 pounds
coke ratio: f/3.93
experience level: intermediate
focal length: 2000mm
optical design: Newton reflector
viewfinder: 9X50
1.25'' single speed focuser
Sky-Watcher brings to you the ultimate DOB experience with the StarGate 20 Dobsonian! Given its remarkable light gathering power, you will be able to catch the most subtle night sky features with your naked eyes. The sturdy giant is reasonably light (138Lb) despite its dimensions, and being easily assembled (30-minute setup time), the whole scope boasts remarkable transportability. If you have the appetite for exceptional planetary and deep space observation, then don't miss out on this high-quality Newtonian system.
PARABOLIC PRIMARY MIRRORS
Features High-Quality Parabolic Primary Mirrors to eliminate spherical aberrations inherent in 'fast' focal length reflectors with spherical primary mirrors. The mirrors are parabolized to bring all the light rays to the same focal point to give sharp, contrasty images, which are full of detail.
SKY-WATCHER DELUXE MIRROR COATINGS
Most reflectors today usually have a coat of aluminum as the mirror surface and then an overcoat of silicon monoxide or silicon dioxide to protect it. Silicon dioxide produces a much more durable coat than silicon monoxide but requires specialized equipment to apply it and is, therefore, more expensive. Protection is needed, because, in most reflectors, the mirror is open to the elements and deterioration of the reflective layer reduces the resolution of the telescope. ALL Sky-Watcher reflectors are Multi-Coated with Silicon Dioxide as a standard for Optimum Durability and Long Term Performance.

Our superior optics just got better
Stargate's feature Sky-Watcher’s exclusive fused conical parabolic mirrors. The fused design allows for thinner mirror construction that provides faster cooling and lighter weight.
Combined with the cast cellular secondary mirror and Sky-Watcher’s exclusive 94% reflectivity coatings, Stargate delivers bright, detailed views of your favorite deep sky objects. The 18 inch model captures 27% more light than our 16 inch, while the 20 inch (a full half meter of aperture) boasts a monster 56% more light gathering power.

Solid foundations, easy assembly
The minimalist all-metal structure of the Stargate produces a sturdy and stable platform while maintaining a convenient and compact footprint. The truss-tubes break down to a very manageable 36 inch length for easy transport. Azimuth and altitude bearings are steel for smooth, steady movement.
Setting up a Stargate is a simple procedure, taking only about 20 minutes. Spring loaded truss anchor points are clearly labeled to eliminate any frustration or confusion. Adjustable feet make leveling a snap.
| Optical Info | |
|---|---|
| Optical Design | Newtonian |
| Mirror Coatings | 94% Aluminum |
| Glass Type | Borosilicate |
| Primary Aperture (mm) | 508 |
| F/Ratio | 3.93 |
| Focal Length (mm) | 2000 |
| Secondary Diameter | 134mm |
| Secondary Obstruction (by diameter) | 26% |
| Secondary Obstruction by Area | 7% |
| Observational Info | |
| Dawes Limit | 0.23 |
| Rayleigh Limit | 0.28 |
| Limiting Mag. | 16 |
| Minimum Magnification | 72 |
| Maximum Magnification | 1000 |
| Light Gathering (compared to next size down) | 23% |
| General Info | |
| Focuser | 1.25" Single Speed Crayford |
| Zenith Eyepiece Height | 79" |
| Dob Base Weight | 40 lbs |
| Upper Cage Weight | 12 lbs |
| Truss Pole Weight | 2.6 lbs each. 16 lbs total |
| Mirror Box Weight | 70 lbs |
| Full Assembled Weight (with weights) | 138 lbs |
| Accessories | |
| Included Finder | 9x50 Finder |
| Included Diagonal | No |
| Included Eyepieces | 28 LET/10mm/Coll. |
| Magnification w/ Included Eyepieces | 71x/200x |
| Included Case | No |
| Corrector | No |
| Other Included Accessories | 2.3lbs counter weights (3), Shroud, Truss clamps |