Optics hub

Compact reflective optics for EmberScope

The optical question is whether a compact reflective train can meet the mission without spending the detector, radiometry, and payload margins needed for a field camera.

Review optical evaluation Review multi-mirror branch Read optical baseline

Current readout · updated 14 June 2026

The four-mirror branch has produced the first physically realizable prescription that reaches the diffraction scale on axis.

All results on this page are ray-trace model outputs; no optics have been fabricated. A full optimization of the four-mirror folded train (curvatures, conics, fold angles, spacings, and focus all free) replaced the earlier bounded screening sweeps. The same work showed that every earlier screening candidate was physically self-obstructed — one mirror sat in the entrance beam — so pre-June-10 candidate metrics are kept only as history.

54 um Centre-field RMS spot, below the 67 um diffraction radius at F/5 and 11 um wavelength.

149.6 mm Package span inside the 150 mm payload cube, with a 0.34 kg optical-head mass proxy.

Conics only The optimizer drove all freeform terms to zero — every surface is a diamond-turnable conic.

F-number At survey plate scale the next design likely needs F/3.2 or faster; at 200 mm EFL, the current optic behaves as a spotter.

Ray-path design rules

Every optical comparison is scored against four practical ray-path rules.

The four checks: do not vignette the beam, keep fold angles small where practical, stop propagation at the image plane to set the detector position, and work toward a flatter image surface.

The optimized prescription satisfies all four: the train is unobscured with 94–97 percent modelled throughput, and the image surface is the flat detector plane. Residual rim-ray clipping at the aperture allowance belongs to the tolerance budget.

Optics evidence map

Start here, then open the detailed pages when a decision needs the numbers.

Optics restart targets

Open the conditional RFS-019 target register before restarting custom prescription work from the survey mission gates.

Optimized prescription

Download the optimized four-mirror prescription (surface table and field metrics, 10 June 2026) — the current reference design for tolerancing and fabrication review.

Optical baseline

Read the compact reflective baseline for the starting architecture, precedent papers, and design rules.

Optical evaluation

Open the evaluation stack for spot, detector-energy, vignetting, tolerance, and thermal-focus rows. Superseded for image quality by the optimized prescription; kept as the methodology record.

Multi-mirror candidates

Compare the screening branches — historical context for how the four-mirror branch was chosen. These seed layouts were later found self-obstructed and are superseded by the optimized prescription.

Optical literature

Read the literature synthesis for compact LWIR and freeform precedent families, including TMA examples.

Mechanical feasibility

Review package and tolerance feasibility before promoting any prescription.

Technical files

Download the technical files: the optimized prescription, the earlier packaging study's geometry exports, validation gates, CAD, and review package.

What remains to prove

The next optics pass must close image quality against the detector, not just package fit.

The open proof points now start with mission targeting. The optics restart target register maps the current RFS-011 answer paths to conditional EFL, F-number, aperture, GSD, and swath targets before the next prescription pass. After that, the remaining optics work is a tolerance budget, stray-light and baffle behaviour, aperture-stop confirmation, and a fabrication package that preserves alignment after mounting.

That evidence should feed the radiometry story so GSD, NETD, and false-positive validation are calculated with measured optical terms rather than broad assumptions.