# snell-0.7.0¶

NIRSpec transforms through the prism.

#### Description

This model does all transforms through the NIRSpec prism:

computes the refraction index as a function of lambda.

Applies Snell’s law through fromt surface.

Rotates to back surface.

Applies reflection from back surface.

Rotates to front surface

Applies Snell’s law through fromt surface.

#### Outline

### Schema Definitions ¶

This node must validate against **all** of the following:

- This type is an object with the following properties:
- prism_angle
**number***Required*The angle of the prism in deg. - kcoef
**array***Required*K coefficients in Sellmeir equation.Minimum length: 3Maximum length: 3Items in the array are restricted to the following types:number - lcoef
**array***Required*L coefficients in Sellmeir equation.Minimum length: 3Maximum length: 3Items in the array are restricted to the following types:number - tcoef
**array***Required*Thermal coefficients of the glass.Minimum length: 6Maximum length: 6Items in the array are restricted to the following types:number - ref_temp
**number***Required*Reference temperature of the glass in [K]. - ref_pressure
**number***Required*Reference pressure of the glass in [ATM]. - temp
**number***Required*System temperature in [K]. - pressure
**number***Required*System pressure in [ATM].

### Original Schema ¶

```
%YAML 1.1
---
$schema: "http://stsci.edu/schemas/yaml-schema/draft-01"
id: "http://stsci.edu/schemas/jwst_pipeline/snell-0.7.0"
tag: "tag:stsci.edu:jwst_pipeline/snell-0.7.0"
title: >
NIRSpec transforms through the prism.
description: |
This model does all transforms through the NIRSpec prism:
- computes the refraction index as a function of lambda.
- Applies Snell's law through fromt surface.
- Rotates to back surface.
- Applies reflection from back surface.
- Rotates to front surface
- Applies Snell's law through fromt surface.
allOf:
- $ref: "tag:stsci.edu:asdf/transform/transform-1.1.0"
- type: object
properties:
prism_angle:
description: |
The angle of the prism in deg.
type: number
kcoef:
description: |
K coefficients in Sellmeir equation.
type: array
items:
type: number
minItems: 3
maxItems: 3
lcoef:
description: |
L coefficients in Sellmeir equation.
type: array
items:
type: number
minItems: 3
maxItems: 3
tcoef:
description: |
Thermal coefficients of the glass.
type: array
items:
type: number
minItems: 6
maxItems: 6
ref_temp:
description: |
Reference temperature of the glass in [K].
type: number
ref_pressure:
description: |
Reference pressure of the glass in [ATM].
type: number
temp:
description: |
System temperature in [K].
type: number
pressure:
description: |
System pressure in [ATM].
type: number
required: [prism_angle, kcoef, lcoef, tcoef, ref_temp, ref_pressure, temp, pressure]
```