Eyepiece Exit Pupil mm Calculator
Ideal visual telescope exit-pupil aperture/magnification; eye clipping and actual field illumination excluded. Model only, not an ephemeris, measured stellar identity or observational guarantee.
Description
Exit-pupil diameter connects aperture with angular magnification.
Exit-pupil diameter connects aperture with angular magnification.1
Its relation to the observer's pupil affects whether the full optical beam can be used. Use Eyepiece Exit Pupil mm Calculator to evaluate the supplied inputs under the model explained below.
When to use Eyepiece Exit Pupil mm Calculator
Use Eyepiece Exit Pupil mm 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 Eyepiece Exit Pupil mm Calculator and understand its results
- Establish the units, measurement scope and model assumptions before entering values.
- Enter Aperture diameter mm, Angular magnification using the field table and validation rules below, then run the tool.
- Read Exit pupil diameter mm; 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 |
|---|---|---|---|
| apertureDiameterMm | Aperture diameter mm | number | Required; constraints below |
| angularMagnification | Angular magnification | number | Required; constraints below |
Enter positive aperture diameter in mm and positive angular magnification. Divide to return exit-pupil diameter in mm. No observer-pupil clipping or optical-configuration inference is added.
exitPupilMm=apertureMm/magnification Use the field order, units and branch conditions described above.
| Output field | Meaning | Value type |
|---|---|---|
| exitPupilDiameterMm | Exit pupil diameter mm | number |
{
"input": {
"apertureDiameterMm": 100,
"angularMagnification": 50
},
"output": {
"exitPupilDiameterMm": 2
}
}Limitations and assumptions
Its relation to the observer's pupil affects whether the full optical beam can be used. 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 True Field of View Eyepiece Calculator for a related task: A field stop limits the angular sky field passed by an eyepiece.
Use Limiting Magnitude From Aperture for a related task: Limiting magnitude depends on observing conditions as well as aperture.
References
-
Eyepiece Exit Pupil mm Calculator — tool.io
Similar or alternative tools
- True Field of View Eyepiece Calculator
A field stop limits the angular sky field passed by an eyepiece.
- Limiting Magnitude From Aperture
Limiting magnitude depends on observing conditions as well as aperture.