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.
| SKU |
S11920 |
| 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 |
|
|
| GoTo |
Yes |
| Object Database |
42,900+ |
| Dual Encoders |
Yes |
| Focuser |
2" Dual Speed Crayford |
| Zenith Eyepiece Height |
74.5" |
| OTA Length (Retract/Ext.) |
78.75" |
| OTA Outer Diameter |
20.5" |
| Dob Base Weight |
66 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) |
155 lbs |
| Accessories |
|
|
| Included Finder |
9x50 Finder |
| Included Diagonal |
No |
| Included Eyepieces |
28 LET/10mm/Coll. |
| Other Included Accessories |
2.3lbs counter weights (3), Shroud, Truss clamps |
