Sky-Watcher SKU: S11900 | Helix SKU: CTS11900
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.
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 and Teflon 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.
Specifications:
| SKU | S11900 |
| UPC | 050234119009 |
| Optical Info | |
|---|---|
| Optical Design | Newtonian |
| Mirror Coatings | 94% Aluminum |
| Glass Type | Borosilicate |
| Primary Aperture (mm) | 458 |
| F/Ratio | 4.14 |
| Focal Length (mm) | 1900 |
| Secondary Diameter | 120mm |
| Secondary Obstruction (by diameter) | 26% |
| Secondary Obstruction by Area | 7% |
| Observational Info | |
| Dawes Limit | 0.25 |
| Rayleigh Limit | 0.31 |
| Limiting Mag. | 15.9 |
| Minimum Magnification | 65 |
| Maximum Magnification | 902 |
| Light Gathering (compared to next size down) | 27% |
| General Info | |
| Focuser | 2" Dual Speed Crayford |
| Zenith Eyepiece Height | 74.5" |
| OTA Length (Retract/Ext.) | 78.75" |
| OTA Outer Diameter | 20.5" |
| Dob Base Weight | 40 lbs |
| Upper Cage Weight | 11 lbs |
| Truss Pole Weight | 2.6 lbs each. 16 lbs total |
| Mirror Box Weight | 62 lbs |
| Full Assembled Weight (with weights) | 129 lbs |
| Accessories | |
| Included Finder | 9x50 Finder |
| Included Diagonal | No |
| Included Eyepieces | 28 LET/10mm/Coll. |
| Magnification w/ Included Eyepieces | 68x/190x |
| Included Case | No |
| Corrector | No |
| Other Included Accessories | 2.3lbs counter weights (3), Shroud, Truss clamps |