Spectroscopic Photometric Parallax Cross-Check Delta Calculator
Signed parallax cross check in same basis with independently covariance-aware DIFFERENCE sigma; no independent-error assumption or distance inversion. Caller independently establishes frames, units, epoch, covariance and instrument context; not an identity, association or astrometric quality certification.
Description
Comparing two parallax estimates needs an independently established uncertainty for their difference.
Comparing two parallax estimates needs an independently established uncertainty for their difference.1
A signed standardized discrepancy is not a combined distance estimate. Use Spectroscopic Photometric Parallax Cross-Check Delta Calculator to evaluate the supplied inputs under the model explained below.
When to use Spectroscopic Photometric Parallax Cross-Check Delta Calculator
Use Spectroscopic Photometric Parallax Cross-Check Delta Calculator to evaluate the supplied inputs under the model explained below. Establish the units, measurement scope and model assumptions before entering values.
How to use Spectroscopic Photometric Parallax Cross-Check Delta Calculator and understand its results
- Establish the units, measurement scope and model assumptions before entering values.
- Enter Spectroscopic parallax mas, Photometric parallax mas, Independent combined difference sigma mas using the field table and validation rules below, then run the tool.
- Read Signed spectroscopic minus photometric mas, Standardized signed difference; 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 |
|---|---|---|---|
| spectroscopicParallaxMas | Spectroscopic parallax mas | number | Required; constraints below |
| photometricParallaxMas | Photometric parallax mas | number | Required; constraints below |
| independentCombinedDifferenceSigmaMas | Independent combined difference sigma mas | number | Required; constraints below |
Enter finite signed spectroscopic and photometric parallaxes in mas and a positive independently combined difference sigma in mas. Subtract photometric from spectroscopic and divide by sigma. Negative estimates are accepted as measurements; no covariance calculation or distance inversion is performed.
differenceMas=spectroscopic−photometric; standardized=difference/sigma Use the field order, units and branch conditions described above.
| Output field | Meaning | Value type |
|---|---|---|
| signedSpectroscopicMinusPhotometricMas | Signed spectroscopic minus photometric mas | number |
| standardizedSignedDifference | Standardized signed difference | number |
{
"input": {
"spectroscopicParallaxMas": 3,
"photometricParallaxMas": 1,
"independentCombinedDifferenceSigmaMas": 2
},
"output": {
"signedSpectroscopicMinusPhotometricMas": 2,
"standardizedSignedDifference": 1
}
}Limitations and assumptions
A signed standardized discrepancy is not a combined distance estimate. 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 Relative Parallax to Absolute Correction Adder for a related task: An absolute-parallax correction adjusts a relative parallax under a calibrated reference frame.
Use Peculiar Velocity versus Local Standard of Rest Residual Calculator for a related task: A local-standard-of-rest comparison requires consistent UVW axes and solar-motion conventions.
References
Similar or alternative tools
- Relative Parallax to Absolute Correction Adder
An absolute-parallax correction adjusts a relative parallax under a calibrated reference frame.
- Peculiar Velocity versus Local Standard of Rest Residual Calculator
A local-standard-of-rest comparison requires consistent UVW axes and solar-motion conventions.