StarHop Navigator – Glossary & Abbreviations
This glossary explains the key terms, abbreviations, and concepts related to StarHop Navigator, starhopping, calibration, and visual observation with Alt/Az Dobsonian telescopes.
Key Terms & Abbreviations
| Term / Abbr. | Meaning | Explanation |
|---|---|---|
| mag | Magnitude | Measure of an object’s brightness. Smaller values = brighter (e.g. −1 very bright, 6 naked-eye limit) |
| Alt | Altitude | Angle above the horizon: 0° = horizon, 90° = zenith |
| Az | Azimuth | Direction along the horizon: 0° = North, 90° = East, 180° = South |
| Alt/Az | Horizontal system | Coordinate system for Dobsonian telescopes |
| RA | Right Ascension | Celestial “longitude” (in hours, 0–24h) |
| Dec | Declination | Celestial “latitude” (−90° to +90°) |
| ENU | East-North-Up | Sensor world coordinate system (x=East, y=North, z=Up) |
| FOV | Field of View | The area visible through an eyepiece or the app |
| TFOV | True Field of View | Actual sky area in degrees |
| AFOV | Apparent Field of View | Apparent field of view of an eyepiece (e.g. 68°, 82°) |
| x / Mag. | Magnification | Telescope focal length / eyepiece focal length |
| Seeing | Atmospheric steadiness | Describes image stability (important for planets & detail) |
| Transparency | Sky clarity | Clarity of the atmosphere (haze, moisture, dust) |
| Bortle | Light pollution | Scale 1–9: 1 = very dark sky, 9 = city centre |
| Zenith | Sky point | Point directly above the observer (Alt = 90°) |
| Drift | Sensor deviation | Slow deviation of gyroscope alignment |
| Calibration star | Reference star | Star with known position used to align the app |
| Calibration | Alignment | Matching sensors to the sky using 1–N stars |
| Local Calibration | Local calibration | Calibration for a limited area of the sky |
| Residual Error | Residual error | Angular deviation between calculated and actual target |
| Push-To | Manual finding | App shows direction, user moves the telescope |
| Starhopping | Star-to-star navigation | Navigating via prominent stars to reach the target |
| Messier (M) | Object catalogue | 110 bright deep-sky objects (M42, M45, …) |
| NGC | Object catalogue | Extensive deep-sky catalogue |
| DSO | Deep-Sky Object | Galaxies, nebulae, star clusters |
| Open Cluster | Open star cluster | Loosely bound star cluster (e.g. M45) |
| Globular Cluster | Globular star cluster | Very dense, spherical star cluster (e.g. M13) |
| Nebula | Nebula | Gas or dust cloud (emission, reflection nebula, etc.) |
| Quaternion | Rotation math | Represents device orientation without gimbal lock |
| Yaw | Rotation around z-axis | Corresponds to azimuth |
| Pitch | Rotation around y-axis | Corresponds to altitude change |
| Roll | Rotation around x-axis | Lateral tilt of the device |
| Compass | Magnetic north | Only rough orientation, not for precision |
| Alignment Quality | Calibration quality | Assessment of current calibration (e.g. traffic light) |
| Best-of-N | Measurement selection | Multiple measurements → best values are used |
| Crosshair | Crosshair | Aiming aid in the eyepiece or on the display |
| Night Mode | Night mode | Red UI to preserve dark adaptation |
Note for Beginners
StarHop Navigator shows you which way to move your telescope. After calibrating with bright stars, the app guides you to your target via push-to.