Proper Motion Position Angle Solver from Components
Proper-motion position angle north-through-east, reject zero-vector undefined direction. Caller independently establishes frames, units, epoch, covariance and instrument context; not an identity, association or astrometric quality certification.
Description
Proper-motion position angle describes direction east of north.
Proper-motion position angle describes direction east of north.1
A zero motion vector has no defined direction. Use Proper Motion Position Angle Solver from Components to evaluate the supplied inputs under the model explained below.
When to use Proper Motion Position Angle Solver from Components
Use Proper Motion Position Angle Solver from Components to evaluate the supplied inputs under the model explained below. Establish the units, measurement scope and model assumptions before entering values.
How to use Proper Motion Position Angle Solver from Components and understand its results
- Establish the units, measurement scope and model assumptions before entering values.
- Enter East ra star mas per year, North dec mas per year using the field table and validation rules below, then run the tool.
- Read Position angle east of north degrees; interpret the units, signs, ordering and unknown-value placeholders described below.
- Correct reported input errors and rerun. Apply successful results according to their specific meanings and check the assumptions before using them in a decision.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| eastRaStarMasPerYear | East ra star mas per year | number | Required; constraints below |
| northDecMasPerYear | North dec mas per year | number | Required; constraints below |
Enter finite signed east RA-star and north declination motion components. Reject a zero-length vector. Compute atan2(east,north), convert to degrees and wrap to [0,360), giving north 0 and east 90. No coordinate transformation or motion uncertainty is inferred.
positionAngleDegrees=wrap360(atan2(east,north)×180/π) Use the field order, units and branch conditions described above.
| Output field | Meaning | Value type |
|---|---|---|
| positionAngleEastOfNorthDegrees | Position angle east of north degrees | number |
{
"input": {
"eastRaStarMasPerYear": 1,
"northDecMasPerYear": 0
},
"output": {
"positionAngleEastOfNorthDegrees": 90
}
}Limitations and assumptions
A zero motion vector has no defined direction. Apply the exact scope and assumptions explained above.
All listed fields require explicit values. Unexpected fields, incorrect types, nonfinite numbers and sparse arrays fail validation. Domain-specific bounds, alignments and supported tokens are explained above; extremely large inputs or outputs can also be rejected. Input errors differ from successful false results, empty match lists and unknown-evidence placeholders.
Alternative or Complementary methods
Use Proper Motion RA Dec Components Total Vector Magnitude Calculator for a related task: Total proper motion combines orthogonal east and north components.
Use Proper Motion Significance Sigma per Year Classifier for a related task: A component's significance compares signed motion with its independently measured uncertainty.
References
Similar or alternative tools
- Proper Motion RA Dec Components Total Vector Magnitude Calculator
Total proper motion combines orthogonal east and north components.
- Proper Motion Significance Sigma per Year Classifier
A component's significance compares signed motion with its independently measured uncertainty.