NEOS chip gap calculation uneven (#152)

Gaps between individual chips was inconsistent, this places the
gaps in the correct places.

Additionally removed the NEOS Band enum

CHANGELOG.md

@@ -16,6 +16,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Horizons orbit table query now includes, M1/2, K1/2, PC, and rotation period.
 
+### Fixed
+
+- NEOS Chip size calculation was slightly incorrect with regard to the placement of the
+  gaps between the chips.
+- NEOS FOV rotation was being calculated in the ecliptic frame, whereas images will be
+  in the equatorial frame. Rotation is now defaulting to the equatorial frame.
+
 
 ## [v1.0.3]
 

src/kete/neos.py

@@ -1,13 +1,21 @@
 import numpy as np
+from .fov import NeosCmos, NeosVisit
+
+
+__all__ = ["sunshield_rotation", "NeosCmos", "NeosVisit", "FOV_WIDTH", "FOV_HEIGHT"]
+
 
 BANDS: list[float] = [4700.0, 8000.0]
 """Effective wavelength of the NC1 and NC2 bands in nm."""
 
 FOV_WIDTH: float = 7.10
-"""Expected effective field of view width in degrees"""
+"""Expected effective field of view width in degrees. Approximate Value."""
 
 FOV_HEIGHT: float = 1.68
-"""Expected effective field of view height in degrees"""
+"""Expected effective field of view height in degrees. Approximate Value."""
+
+FOV_CHIP_GAP: float = 0.11
+"""Expected effective gap between individual chips in degrees. Approximate Value."""
 
 ZERO_MAGS: list[float] = [170.662, 64.13]
 """Zero point magnitude for nc1 and nc2"""

src/kete/rust/fovs/definitions.rs

@@ -1,4 +1,4 @@
-use kete_core::fov::{self, NeosBand};
+use kete_core::fov::{self};
 use kete_core::fov::{FovLike, SkyPatch};
 use nalgebra::Vector3;
 use pyo3::{exceptions, prelude::*};
@@ -607,7 +607,7 @@ impl PyNeosCmos {
             subloop_id,
             exposure_id,
             cmos_id,
-            band.into(),
+            band,
         ))
     }
 
@@ -677,11 +677,7 @@ impl PyNeosCmos {
     /// Band Number
     #[getter]
     pub fn band(&self) -> u8 {
-        match self.0.band {
-            NeosBand::NC1 => 1,
-            NeosBand::NC2 => 2,
-            NeosBand::Undefined => 0,
-        }
+        self.0.band
     }
 
     /// Rotation angle of the FOV in degrees.
@@ -738,22 +734,23 @@ impl PyNeosVisit {
         exposure_id: u8,
         band: u8,
     ) -> Self {
-        let pointing = pointing.into_vector(crate::frame::PyFrames::Ecliptic);
+        let pointing = pointing.into_vector(crate::frame::PyFrames::Equatorial);
         let pointing = pointing.raw.into();
+        let observer = observer.as_equatorial().unwrap().0;
         PyNeosVisit(fov::NeosVisit::from_pointing(
             x_width.to_radians(),
             y_width.to_radians(),
             gap_angle.to_radians(),
             pointing,
             rotation.to_radians(),
-            observer.0,
+            observer,
             side_id,
             stack_id,
             quad_id,
             loop_id,
             subloop_id,
             exposure_id,
-            band.into(),
+            band,
         ))
     }
 

src/kete_core/src/fov/neos.rs

@@ -6,31 +6,6 @@ use crate::prelude::*;
 use nalgebra::Vector3;
 use serde::{Deserialize, Serialize};
 
-/// NEOS bands
-#[derive(Debug, Clone, Copy, Deserialize, Serialize, PartialEq)]
-pub enum NeosBand {
-    /// No Band defined.
-    Undefined,
-
-    /// NEOS NC1 Band.
-    NC1,
-
-    /// NEOS NC2 Band.
-    NC2,
-}
-
-/// Convert a NEOS band from u8
-/// 1 is NC1 2 is NC2, everything else is Undefined.
-impl From<u8> for NeosBand {
-    fn from(value: u8) -> Self {
-        match value {
-            1 => NeosBand::NC1,
-            2 => NeosBand::NC2,
-            _ => NeosBand::Undefined,
-        }
-    }
-}
-
 /// NEOS frame data, a single detector on a single band
 #[derive(Debug, Clone, Deserialize, Serialize)]
 pub struct NeosCmos {
@@ -62,7 +37,7 @@ pub struct NeosCmos {
     pub exposure_id: u8,
 
     /// Wavelength band
-    pub band: NeosBand,
+    pub band: u8,
 
     /// CMOS ID
     /// ID number of the CMOS chip, 0, 1, 2, or 3
@@ -83,7 +58,7 @@ impl NeosCmos {
         subloop_id: u8,
         exposure_id: u8,
         cmos_id: u8,
-        band: NeosBand,
+        band: u8,
     ) -> Self {
         let patch =
             OnSkyRectangle::new(pointing, rotation, NEOS_WIDTH, NEOS_HEIGHT, observer.frame);
@@ -164,7 +139,7 @@ pub struct NeosVisit {
     pub exposure_id: u8,
 
     /// Wavelength band
-    pub band: NeosBand,
+    pub band: u8,
 }
 
 impl NeosVisit {
@@ -235,7 +210,7 @@ impl NeosVisit {
         loop_id: u8,
         subloop_id: u8,
         exposure_id: u8,
-        band: NeosBand,
+        band: u8,
     ) -> Self {
         // Rotate the Z axis to match the defined rotation angle, this vector is not
         // orthogonal to the pointing vector, but is in the correct plane of the final
@@ -250,29 +225,34 @@ impl NeosVisit {
         // orthogonal to the two existing vectors.
         let up_vec = pointing.cross(&left_vec);
 
-        // +------+-+------+-+------+-+------+   ^
-        // |  1   |g|  2   |g|  3   |g|  4   |   |
-        // |      |a|      |a|      |a|      |   y
-        // |      |p|      |p|      |p|      |   |
-        // +------+-+------+-+------+-+------+   _
-        // <-cf->    x ->
+        // +-------+-+-------+-+-------+-+-------+   ^
+        // |       |g|       |g|       |g|       |   |
+        // |   1   |a|   2   |a|   3   |a|   4   |   y
+        // |       |p|       |p|       |p|       |   |
+        // +-------+-+-------+-+-------+-+-------+   -
+        // |            <---- x ----->           |
         //
-        // pointing vector is in the middle of the 'a' in the central gap.
+        // Pointing vector is in the middle of the 'a' in the central gap.
 
         // the Y direction is bounded by 2 planes, calculate them one time
         let y_top: Vector3<f64> = rotate_around(&up_vec, left_vec, y_width / 2.0);
         let y_bottom: Vector3<f64> = rotate_around(&(-up_vec), left_vec, -y_width / 2.0);
 
         let half_gap = gap_angle / 2.0;
 
+        // chip width in the x direction:
+        // 4 * chip_width + 3 * gap_angle = x_width
+        // chip_width = (x_width - 3 * gap_angle) / 4
+        let chip_width = (x_width - 3.0 * gap_angle) / 4.0;
+
         // for each chip calculate the x bounds
         let chip_1_a: Vector3<f64> = rotate_around(&left_vec, up_vec, -x_width / 2.0);
-        let chip_1_b: Vector3<f64> = -rotate_around(&left_vec, up_vec, -x_width / 4.0 - half_gap);
-        let chip_2_a: Vector3<f64> = rotate_around(&left_vec, up_vec, -x_width / 4.0 + half_gap);
+        let chip_1_b: Vector3<f64> = -rotate_around(&left_vec, up_vec, -x_width / 2.0 + chip_width);
+        let chip_2_a: Vector3<f64> = rotate_around(&left_vec, up_vec, -chip_width - half_gap);
         let chip_2_b: Vector3<f64> = -rotate_around(&left_vec, up_vec, -half_gap);
         let chip_3_a: Vector3<f64> = rotate_around(&left_vec, up_vec, half_gap);
-        let chip_3_b: Vector3<f64> = -rotate_around(&left_vec, up_vec, x_width / 4.0 - half_gap);
-        let chip_4_a: Vector3<f64> = rotate_around(&left_vec, up_vec, x_width / 4.0 + half_gap);
+        let chip_3_b: Vector3<f64> = -rotate_around(&left_vec, up_vec, chip_width + half_gap);
+        let chip_4_a: Vector3<f64> = rotate_around(&left_vec, up_vec, x_width / 2.0 - chip_width);
         let chip_4_b: Vector3<f64> = -rotate_around(&left_vec, up_vec, x_width / 2.0);
 
         // make the patches for each chip