Sky-Watcher SKU: S11500 | Helix SKU: CTS11500
| SKU | S11500 |
| UPC | 050234115001 |
| Optical Info | |
|---|---|
| Optical Design | Mak-Cass |
| Mirror Coatings | 94% Aluminum |
| Lens Coatings | Fully Multi-Coated |
| Glass Type | BK7/Borosilicate |
| Primary Aperture (mm) | 90 |
| F/Ratio | 13.9 |
| Focal Length (mm) | 1250 |
| Secondary Diameter | 29mm |
| Secondary Obstruction (by diameter) | 32% |
| Secondary Obstruction by Area | 10% |
| Observational Info | |
| Dawes Limit | 1.29 |
| Rayleigh Limit | 1.55 |
| Limiting Mag. | 12.3 |
| Minimum Magnification | 13 |
| Maximum Magnification | 177 |
| Light Gathering (compared to next size down) | 27% |
| General Info | |
| Focuser | Primary Mirror |
| OTA Length (Retract/Ext.) | 11" |
| OTA Outer Diameter | 4.125" |
| OTA Weight (with accessories) | 3.6 |
| Accessories | |
| Included Finder | Red Dot |
| Included Diagonal | 1.25" Star Diagonal |
| Mounting Accessories | 1/4-20" Foot |
| Included Eyepieces | 25/10 Wide Angle |
| Magnification w/ Included Eyepieces | 50x/125x |
| Included Case | Yes |
| Corrector | No |