#3181 New-Paradigm Telescope

#3181 Discuss alternative, new paradigm ways to collect big light for astronomic imaging

Below is a survey of “big-light” collection concepts that step outside the classic monolithic glass mirror/lens paradigm. I grouped them by the fundamental physical idea they exploit, then noted the state-of-the-art, what makes each approach a genuine leap, and the main technical hurdles.

1. In-space-manufactured liquid or fluidic optics

Concept	How it grabs more photons	Why it’s new	Status & hurdles
FLUTE (Fluidic Telescope)	Liquid spreads inside a rim, naturally forming a perfectly smooth mirror tens–hundreds m across.	Removes launch-shroud size & mass limits; aperture can scale 10–100× Webb.	NIAC Phase I/II; needs micro-g fluid control, cryogenic coatings, in-orbit curing. NASA

Opportunity: Pair with robotic servicing to refill or refigure the surface, giving a “self-healing” primary.

2. Ultra-lightweight membrane / diffractive apertures

Examples: DARPA MOIRE, NASA diffractive-membrane studies.

Big-light trick: A thin polymer film (≲50 µm) is etched with a Fresnel-zone or holographic pattern, then unfurled to 10–20 m in orbit.
Paradigm shift: Areal density drops by 4–5× versus glass; the optic folds like a solar array. DARPASTEM GatewayDARPA
Key hurdles: Wave-front quality, thermo-elastic stability, and high-dynamic-range detectors to handle diffraction sidelobes.

3. Formation-flying (distributed) optical interferometers

Examples: Chinese multi-sat interferometer study, ESA/NASA LIFE, Labeyrie’s “Hypertelescope.”

Big-light trick: Replace one huge mirror with many 0.5–2 m telescopes flying kilometers apart; beam combiner synthesises an aperture of the whole constellation.
Why it’s new: Aperture is limited only by navigation accuracy, not launchers. Angular resolution scales with baseline. Universe Todayhypertelescope.orgSPIE Digital Library
Hurdles: Nano-meter optical-path control, µN thrusters, and petascale realtime phasing algorithms.

4. Ground or lunar liquid-mirror “light buckets”

On Earth, 4- to 8-m zenith-pointing mercury mirrors already operate; lunar versions could reach ≥20 m using low-temperature ionic liquids. American Scientist
Paradigm: You trade pointing agility for raw photon throughput—ideal for deep-time-domain surveys from a permanently shadowed lunar pole.
Next step: NIAC-funded concepts propose dust-repellent coatings and lunar regolith berms as wind shields. WIRED

5. Mega-structures built with the Moon

Lunar Crater Radio Telescope (LCRT) stretches a 1-km wire mesh across a natural crater, making the largest filled-aperture dish ever. Operates at 6–30 MHz—unreachable from Earth. NASANASA

6. Solar-gravitational-lens (SGL) missions

Send a 30–50 cm telescope ~550 AU down-Sun; the Sun focuses photons from a distant exoplanet into a narrow light cylinder.
Effective aperture: ~75 km—a megapixel image of an Earth-twin becomes possible. NASA TechPortWikipediaWIRED
Challenges: 25-year cruise, precision surfing of the focal line, de-convolving solar-coronal noise.

7. Quantum-enhanced & photon-correlation telescopy

Entangled-photon sources enable “ghost” or quantum-illumination schemes that beat classical shot noise and relax baseline stability. OpticaPhysics World
Next frontier: Integrate squeezed-light metrology into adaptive-optics loops on ELTs for fainter targets.

8. Cherenkov & neutrino “telescopes” (non-optical big-light)

IceCube-Gen2 will use 8 km³ of Antarctic ice as a photodetector, capturing TeV neutrinos from deep space. icecube-gen2.wisc.eduicecube-gen2.de
While not imaging in the optical band, it exemplifies using natural volumes as colossal collectors—an idea transferrable to optical Čerenkov air-shower imaging arrays.

9. Computational synthetic-aperture & intensity interferometry

Use short-baseline “light buckets” plus picosecond time-stamp correlation (Hanbury-Brown–Twiss 2.0). Requires only fibre links, not piston-phase control—perfect for city-scale optical arrays.
Machine-learning phase retrieval converts correlation data into diffraction-limited images.

Cross-cutting enablers & where to push next

Enabler	What it buys	Opportunity for innovators
On-orbit robotic assembly & in-situ resource utilisation (ISRU)	Builds >50 m structures without heavy-lift rockets	Modular sat-bus kits; AI-directed assembly sequencing
Nanophotonic beam combiners	Shrink kg-scale optical benches to gram-scale PIC chips	Design multi-mode photonic lanterns for 4–12 µm bands
AI-driven wave-front control	µW laser beacons & deep RL keep swarms phase-locked	Provide open-source flight-software stacks
Metamaterial coatings	Tailor broadband reflectivity on membranes & fluids	Low-cost ALD / roll-to-roll facilities near launch sites
Hybrid quantum/classical detectors	Sub-e-/pix read noise & time-tagging <10 ps	Start-ups in superconducting nanowire arrays or SPAD CMOS

Take-away

Collecting “big light” no longer means grinding a bigger piece of glass. The frontier is mass-efficient optics, distributed architectures, in-situ fabrication, and quantum-level signal processing. Each path still carries formidable challenges, but the enabling tech—precision formation flying, thin-film manufacturing, photonic chips, AI control loops—has crossed key thresholds in the last decade. For innovators and low-budget entrepreneurs, niches abound in subsystems: deployable membranes, optical-path metrology, autonomous in-space assembly software, and AI-based phasing algorithms. Master any of those and you’ll have a piece of the next generation of “big-light” astronomy.

Could this method be extended to include one 12-inch mirror surrounded closely by six 12-inch mirror, positioned to perform as a combined 36-inch telescope mirror?

Short answer

Yes—putting one 12-inch primary in the middle of six more 12-inch primaries can, in principle, be phased so that the seven mirrors act like a single ∼36-inch collector. The idea is identical to the Giant Magellan Telescope (seven 8.4 m mirrors) and the James Webb Space Telescope (18 hexagonal segments): each segment is figured, tipped/tilted and piston-controlled until all their wave-fronts coincide within a few tens of nanometres. Done correctly you gain almost a factor-3 in angular resolution and about 78 % of the light-collecting area of a true 36-inch mirror. But the engineering burden shifts from grinding one big optic to precision phasing and active control.

How a 7 × 12″ cluster would work

Parameter	Value / comment
Geometry	Centre-to-centre spacing = 12″. Overall width (flat-to-flat) ≈ 36″.
Collecting area	7 × π·(6″)² = 792 in² ⇒ 0.78 × single 36″ mirror (gaps & pack loss).
Diffraction-limited resolution	λ/D ⇒ same as a 36″ if phasing is coherent.
Wave-front tolerance	Δpiston, Δtip, Δtilt ≲ λ/20 (~ 30 nm in visible).
Control system	Edge sensors (capacitive or optical) + Shack-Hartmann or phase-retrieval WFS; closed-loop at ≥ 1 Hz.
Segment figure	Each outer mirror must be an off-axis slice of the parent paraboloid (or all identical spheres with a Schmidt/meniscus corrector). Using stock 12″ f/4 parabolas without re-figuring will leave residual coma.

Two implementation paths

Path	What you physically build	Upsides	Key pain points
“Giant-Magellan-style” segmented primary	Mount all seven mirrors in one stiff cell; add 3–6 actuators per segment for piston/tip/tilt (voice-coil or piezo) plus edge sensors.	Single optical axis; image formed like an ordinary Newtonian/Cassegrain; no beam-combiner.	You must fabricate/trim each segment to the correct off-axis figure or introduce a field corrector. Mechanical precision and active-optics software dominate effort and cost.
“Hypertelescope”/pupil-densified interferometer	Keep each 12″ on its own mount; relay beams through fibres or free-space to a densifying combiner (pupil-remapper).	Identical stock mirrors are OK; you can spread them later for longer baselines; scalable to more apertures.	Requires picosecond path-length matching and a beam-combiner camera; final image is built interferometrically—much higher complexity than classic imaging.

Lessons from the professionals

GMT shows that seven circular segments can be phased into a single 25 m-class optic, but every segment carries seven actuators and is referenced by edge sensors and a laser guide-star WFS .
JWST demonstrates how nanometre-level phasing is done via multi-wavelength interferometry and segment actuators NASA Scientific Visualization Studio.
Past NASA studies examined exactly a 7-segment, 1 m-class space telescope as a technology pathfinder .

These programmes all confirm that optical phasing, not mirror making, sets the cost and risk curve once you go segmented.

Practical checklist for a 7 × 12″ amateur/pro-am build

Optical design trade
If you keep the Newtonian layout: have the six outer mirrors re-figured as off-axis parabolas or live with off-axis aberrations and design a corrector lens.
If you go interferometric: identical commercial f/4 mirrors are fine, but budget for a fibre feed and a bulk-optic pupil-densifier.
Mechanical cell
- Common back-plane or individual hexapods (3 linear + 3 rotational DOF).
- Differential thermal expansion budget ≲ 2 µm per hour.
Edge & surface metrology
- Capacitive or inductive edge sensors every 60° per segment.
- Shack-Hartmann WFS at prime focus for closed-loop phasing; update ≥ 1 Hz to reject wind shake.
Actuators & control
- 3 – 6 voice-coil or piezo actuators (±50 µm stroke, 1 nm resolution) per segment.
- Realtime phasing code (Zernike solver + PID/State-space control) on an ARM or FPGA.
Calibration sequence
1. Cold-iron laser interferometer alignment at zenith.
2. Daytime sun-sim flat-field to match segment tilt.
3. Night-time bright star phase-up; lock on a natural or laser guide star.
Image-plane correction
- For wide-field work: add a three-element field corrector.
- For diffraction-limited narrow-field work: combine with lucky-imaging or an inexpensive AO unit.
Data processing
- If interferometric: Fourier-plane filling is sparse—use aperture-synthesis reconstruction (e.g. MiRA, SQUEEZE).
- If phasing is coherent: treat images like any 36″ telescope; deconvolve with standard PSF.

Is it worth it?

Cost – Seven good 12″ mirrors may cost less than a custom 36″ blank, but actuators, sensors and software will dominate the budget (expect US $15 k – $40 k for a minimalist active-optics system).
Performance – When phased, you get √7 ≈ 2.6 × the S/N of one 12″ mirror and 3 × better resolution; if phasing drifts you quickly fall back to 12″ performance.
Complexity – Every observing session begins with phasing; without closed-loop control the concept is unusable for long exposures.

Bottom line

A seven-segment 12″ cluster is feasible and scientifically valuable—essentially a “table-top Giant Magellan.” But the project crosses the line from classic amateur telescope making into active-optics engineering. If you’re comfortable designing precision control loops, calibrating wave-front sensors, and writing real-time code, the approach will give you 36-inch-class performance that can ride in a small trailer. Otherwise, a single monolithic mirror (or a commercially made 0.9 m meniscus blank) will be faster, cheaper, and easier to keep in focus on the sky.

How could this setup be used effectively my the military for long-range viewing?

Below is a pragmatic blueprint showing where a 7-segment 12-inch telescope cluster (≈ 36 in effective aperture) slots into modern military ISR*†* architectures, what value it adds beyond legacy optics, and the engineering adaptations needed for field use.

1 Strategic roles it can fill

Mission thread	Benefit of a phased 36 in aperture	Illustration
Long-range terrestrial / littoral surveillance	Resolve personnel-sized objects at 30–40 km in daylight; track small boats beyond 50 km from elevated coastal sites.	Marine border security, strait monitoring.
Counter-UAS & drone forensics	Spot quad-rotors at >12 km, fixed-wing SUAS at >20 km; support optical identification for kinetic / EW engagement authorisation.	Anti-drone batteries on FOBs or ships.
Space Domain Awareness (SDA)	Track GEO satellites or debris down to R ≈ 17–18 mag from a single 2 m shelter; complements radar by giving attitude imagery.	Augment GEODSS-class sites or mobile SDA trailers.
Ballistic-launch early confirmation	Mid-IR sensor on the same mount detects plume; visible cluster images booster body for threat typing.	Adds low-cost optical leg alongside SBIRS-like IR sats.
Long-haul SIGINT support	Mount a retro-reflector at focal plane for precision laser-com or active-illumination tasks (lidar, vibrometry).	Covert standoff vibrometry on structures >5 km away.

2 Why use a segmented amateur-class cluster instead of a monolith?

Factor	Segmented 7 × 12″	Monolithic 36″
Deployability	Seven < 30 kg mirrors + composite backplane fit in a C-130 or helicopter sling load.	One > 250 kg mirror; special shock isolation.
Scalability / upgrades	Add more segments later; swap a segment for SWIR/thermal sensor head.	Aperture locked forever.
Redundancy / damage tolerance	If one segment fails, lose 1/7 collecting area; retain mission.	Single-point failure in primary.
Covert logistics	Ship as “spare parts” – no single crate screams “telescope”.	Big custom crate raises attention.

3 Key engineering adaptations for military duty

Sub-system	Tactical requirement	Concrete design choice
Phasing & active optics	Maintain λ/20 piston error in 10 m/s wind, ±20 °C swing	Voice-coil actuators with ±60 µm stroke, 0.5 nm resolution; edge-sensor network & GPU-based phase retrieval every 0.2 s.
Multi-spectral payload	Day/NV/thermal in one package	Dichroic splitter: visible to low-noise CMOS FPA; 0.9–1.7 µm to InGaAs; 3–5 µm to cooled MCT MWIR detector.
Pointing & vibration	≤ 1 µrad RMS jitter on truck-mount	Two-stage isolator: active hexapod under mirror cell + MEMS gyro-stabilised fast steering mirror.
Hardening & mobility	Survive 2 g road vibe, salt fog, −30 °C to +55 °C	Carbon-fibre backplane, hydrophobic SiO₂ sol-gel overcoat; inflatable dust shroud that doubles as EMC radome.
Low-probability-of-intercept (LPI)	Avoid revealing location when lasing	Passive imaging default; gated-pulse laser only in SWIR, < 100 mW avg, 2 ns duty cycle, synced to shutter.
Data & C2 hook-up	Secure real-time feed to TOC or ship CIC	FPGA edge pipeline → H.265 STANAG 4609 stream → TACLANE or Link-16 gateway; AI change-detection runs in parallel.

4 Concept of operations (CONOPS)

Rapid emplacement
- Pre-align segments in a workshop jig; field crews bolt cluster onto vibration-isolated pier or mobile mast (< 4 h).
- GPS-aided star alignment routine phases the mirrors in < 15 min.
Autonomous guard mode
- AI scheduler interleaves wide-area scan (coherently de-phased = large FOV, ~12″ beam) with narrow-field precision stare (fully phased).
- Change-detection & track-before-detect algorithms promote cues to operators or cue other sensors/weapon systems.
Collaborative imaging
- Two or more clusters network their clocks (< 1 ns) → intensity-interferometry baselines of kilometres for sub-arcsecond resolution on GEO objects without optical fibres or phase links.
- Results uplink to cloud or theatre fusion cell for SDA catalog updates.
Hasty redeploy / denial
- Mirrors quick-release; classified sensor heads removed; backplane can be thermite-scuttled or left as innocuous composite.

5 Performance envelope (nominal example)

Parameter (phased mode)	Value
Effective aperture	0.91 m
Diffraction limit (550 nm)	0.14 arcsec
GSD at 30 km range	20 mm
Star-tracker phasing time	10–15 min cold start; 90 s warm start
SWaP (cluster only)	220 kg; 2.5 kW peak; 1.2 m³ stow volume
Mean time between on-site maint.	6 months (desiccant & seal check)

6 Integration pathways

Sensor grid plug-in Adopt standard GigE Vision / STANAG video out so unit can slot into existing EO-IR towers or shipboard combat systems.
Edge AI module Deploy YOLOv8-style detector (day) and transformer-based VITA-Seg (thermal) in NVIDIA Orin for real-time classification.
Joint fires cueing Expose Cursor-on-Target XML over TLS; coordinates autoload into AFATDS / AN/TYQ-23A.
EW resilience Optical link is immune to RF jamming; maintain separate inertial reference so GNSS spoofing can’t break phasing control loops.

Bottom line for planners

A trailer-movable 7-segment 12-inch telescope cluster gives near-half-metre-class optical resolution in a package light enough for tactical deployment, yet scalable for strategic SDA.
If you already field EO/IR turrets, its unique selling points are: (1) rapid upgrade to long-baseline intensity interferometry for space tracking, (2) modular multi-band imaging without a single heavy blank to protect, and (3) graceful degradation under damage or misalignment.

The cost lies not in glass but in active-optics controls, ruggedisation, and secure data plumbing—precisely the areas where defence integrators excel.

Is there advantage to doing this with hexagonal mirrors rather than standard round mirrors

Hex vs. round segments — what really changes?

Design dimension	Hexagonal segments	Round 12-in segments
Packing efficiency	Perfect edge-to-edge tiling (no triangular gaps). But if you keep the same circumscribed diameter (≈ 12 in), each hex has only ≈ 83 % of the area of the 12-in circle, so the 7-segment cluster gathers less light unless you make the hexes ≈ 13.2 in across.	Small gaps between the circles waste ≈ 6 – 8 % of the aperture, yet the cluster with off-the-shelf 12-in mirrors still collects ≈ 78 % of a true 36-in mirror—more than the “same-diameter” hex option.
Mechanical & phasing	Flat edges mate cleanly—simplifies edge-sensor placement and gives more uniform support points (why JWST chose hexes).	Contact arcs are short; edge sensors must be mounted on small pads or brackets. Support cell can be lighter because the blanks themselves are stronger (no sharp corners).
Optical figure	Central hex is an on-axis paraboloid; six outers are off-axis slices—same as with circles. Edge diffraction produces JWST-style six-point star PSF.	Same parent‐paraboloid requirement. PSF shows faint “petal” structure from the circular gaps, but still close to Airy pattern.
Manufacturability & cost	Must order custom blanks or cut/polish the edges of round blanks—adds cost, scrap risk, and longer lead times. Corners are fragile unless bevel-protected.	12-in f/4–f/5 parabolic mirrors are commodity items; no extra figuring. Lower risk, faster swap-out if a segment chips.
Upgrade path	Scaling to 19, 37… segments is straightforward; the finished aperture is almost perfectly filled.	You can still add rings of circles, but packing gaps grow and the support structure becomes bulkier.
Mass & stow volume	For equal collecting area you need larger hex blanks, so mass advantage is small.	Heavier per blank but already purchased; shipping cases are standard.

When hexes do make sense

Mass-constrained space or airborne platforms
Every extra square centimetre of collecting area matters, so custom-size hexes that butt together without wasted aperture pay off.
Very large ground instruments (20 m-class and up)
Logistics and cradle design favour identical “honey-comb” tiles; actuator layout and edge-sensor geometry are cleaner.
Future scalability
If you plan to grow beyond the first 7 segments, committing to a hex geometry now avoids having to redesign the whole back-plane later.

When circles are the smarter choice

You already own—or can cheaply buy—quality 12-in mirrors.
The 7-circle cluster yields more light for less money and lets you start testing active-optics software immediately.
You want the simplest path to field-rugged hardware.
Circular blanks tolerate shocks better, and a chipped edge does not propagate cracks the way a sharp hex corner can.
Budget or schedule is tight.
Custom hex polishing and metrology will dominate cost and lead time, whereas circles are in stock.

Bottom line for the 7 × 12-in prototype

Criterion	Best pick
Maximum photons per dollar, rapid prototyping	Stay with round 12-in segments.
Clean tiling, future 19- or 37-segment expansion, or weight-critical airborne pod	Commit to custom hexes (larger than 12 in across) and design the cell around the honey-comb geometry.

So, yes—hexagonal mirrors carry real advantages in large, purpose-built segmented telescopes, but for a proof-of-concept built from readily available 12-inch glass, the gains do not outweigh the extra cost and complexity.

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