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 |
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) |
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 #)
