Maximum Transit Altitude Calculator
Uppermeridianmaximumaltitude90−|φ−δ|,signednegativealtitudesretained,not assume allstarstransitabovehorizon. Actual independent model/unit/frame/epoch/calibration and applicable measurement established;not precise ephemeris,forecast,geodesy operation,identity or safety approval.
Description
A star’s upper meridian transit is its highest altitude during an ideal diurnal circle.
A star’s upper meridian transit is its highest altitude during an ideal diurnal circle.1
This calculator gives that geometric altitude from observer latitude and star declination, with a negative result when the upper transit is below the horizon.
When to use Maximum Transit Altitude Calculator
Use this tool to apply the stated maximum transit altitude calculator operation with an explicit input and unit basis.
How to use Maximum Transit Altitude Calculator and how it works
- Establish the measurement basis and units described above.
- Enter actualLatitudeDegrees, actualDeclinationDegrees and run the tool.
- Read result.value using the output meanings below.
- If input is rejected, correct the stated type, range, ordering or alignment issue and rerun; review successful results under the declared convention.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| actualLatitudeDegrees | Latitude Degrees. Units, ordering and applicable branch are specified in the algorithm. | number | required; finite; further conditions in the algorithm |
| actualDeclinationDegrees | Declination Degrees. Units, ordering and applicable branch are specified in the algorithm. | number | required; finite; further conditions in the algorithm |
Require latitude and declination within −90 to 90 degrees inclusive. Subtract their absolute difference from 90; do not clip negative altitude or add atmospheric refraction.
upperTransitAltitudeDegrees = 90−abs(latitude−declination) Apply the declared units, ordering and branch conditions.
| Output field | Meaning | Value type |
|---|---|---|
| result | Object containing the declared output fields. | object |
| result.value | Geometric altitude in degrees; a negative upper transit is retained. | number |
{
"input": {
"actualLatitudeDegrees": 30,
"actualDeclinationDegrees": 20
},
"output": {
"result": {
"value": 80
}
}
}Limitations and assumptions
The output applies the declared operation to the values you supply. Establish the measurement basis, units, coefficients and any caller-selected rules before interpreting it. The tool does not independently collect or verify observations or decide whether a model or reference applies.
Supply explicit required fields with the documented types and dense aligned arrays. Unknown fields, wrong types and nonfinite numbers are rejected. Branch-specific constraints are explained above. A returned boolean, signed difference or tied result follows the stated convention; an input error instead means the required input contract was not satisfied. Very large inputs or outputs may be rejected by shared resource limits.
Alternative or Complementary methods
For a related operation, use Celestial Equator Altitude By Latitude. The celestial equator’s upper meridian intersection has an altitude determined by observer latitude.
For a related operation, use Circumpolar Declination Threshold By Latitude. Circumpolar geometry describes declinations that remain on the visible side of an ideal horizon during rotation.
References
-
Maximum Transit Altitude Calculator — tool.io
Similar or alternative tools
- Celestial Equator Altitude By Latitude
The celestial equator’s upper meridian intersection has an altitude determined by observer latitude.
- Circumpolar Declination Threshold By Latitude
Circumpolar geometry describes declinations that remain on the visible side of an ideal horizon during rotation.