# Coronagraphs

VAMPIRES has a suite of classic Lyot-style coronagraphs (CLC) comprised of four focal plane masks and a single Lyot stop. In November 2023 a double-grating vector vorted (DGVVC) mask was installed (PI: David Doelman). Lastly, a shaped pupil mask resistent to low wind effect (redundant apodizing pupil; RAP) was installed in September 2023 (PI: Lucie Leboulleux).

## Focal Plane Masks

The focal plane masks for VAMPIRES are four opaque circular masks, each with their own 3" x 3" fieldstop. Each mask corresponds to roughly 2, 3, 5, and 7 $\lambda/D$ inner working angle (IWA).

| Mask | IWA (mas) | Notes |
| - | - | - |
| CLC-2 | 37 | Hard to use, lots of leakage |
| CLC-3 | 59 | Typical mask for polarimetric observations or good wavefront correction |
| CLC-5 | 105 | Typical mask for okay wavefront correction |
| CLC-7 | 150 | Not well-matched to Lyot stop |
| DGVVC | 61 | **(Experimental)** Not compatible with polarimetry, hard to align |

```{image} 20230913_vampires_iwa.png
```

## Lyot Stops

There are three Lyot pupil stops.

| Stop | Geom. through. (%) | Notes |
| - | - | - |
| LyotStop-S | 95.9 | Semi-reflective aluminum mask |
| LyotStop-M | 85.7 | Semi-reflective aluminum mask |
| LyotStop-L | 61.5 | Reflective gold mask on glass substrate (causes pupil beam shift) |

```{image} lyotstop.png
```

### Advanced Details

The CLC focal plane masks and Lyot stop are patterned using metallic vapor deposition on top of an AR-coated optical flat (EO #)

```{image} focal_plane_masks.jpeg
:width: 600 px
```