Fun With Science / Globe Deconstruction / Unknown Luminaries · pages 155–157
What the book gets right about how planetary photographs are made, and why granting all of it costs the argument nothing.
Three pages of the Unknown Luminaries chapter, pp. 155–157, are given to how planetary photographs are made, under the heading “Image stacking + Deconvolution = Reality?” The two arguments that follow both rest on photographs, one captioned “(image stacked and edited)” in the author’s own hand.
The suspicion of processing: reasonable, and partly correctAs a load-bearing objection: aimed at the decoration
Where this lands
The claim: stacking and deconvolution put the detail into planetary photographs rather than drawing it out, so the pictures cannot stand as evidence. The verdict: the first half is partly right, and conceded below; the second does not follow, because the argument is aimed at detail when the evidence was always motion.
Sharpening really can manufacture detail, and a reader is entitled to want the pipeline explained. But the case for a moving Earth was built on where planets are, and when — measurements that need a dot, not a picture, and most of which predate photography. Grant that every processed planetary image is worthless and Neptune is still where Le Verrier said it would be, found about one degree from his calculated place on 23 September 1846. And on a working amateur’s raw video of Jupiter, stacking 3,215 frames cut the noise power at fine scales by 2,140× while leaving the coarse structure untouched — removing only what lay beyond the 0.389″ a 356 mm telescope can resolve, where nothing real could have been.
The stacking removed only what a 356 mm mirror cannot resolve. Software inventing detail has no way of knowing where that limit is.
An arcsecond (″) is 1/3,600 of a degree; Jupiter is about 40 across. The atmosphere — the seeing — blurs any point of light to between one and four arcseconds. A telescope’s own limit is set by its aperture, θ = 1.22λ/D, and no processing passes it.
p. 156 quotes a working tutorial from the astrophysicist behind the Astraveo channel (the book prints “Astaveo”), whose flat-Earth challenge video the chapter uses throughout: capture around ten thousand frames with FireCapture, stack them in AstroSurface. The book’s reply is “Is he implying that Photoshop is the best method to prove to myself that the Earth is not flat?” p. 157 sets a raw frame beside a processed one — “Real Jupiter” against “Jupiter 4.0?” — over a quotation about a wavelet setting that “brings out a lot of the detail,” captioned “How to manipulate a photo to achieve the desired planet 101.”
Most of this is put as questions, and we grade it as put; the caption is the unhedged form the later pages rely on. The charge is that the detail is put in rather than drawn out, and by p. 161 it has become “Do these deconvoluted and sharpened images even resemble an 88,800-mile-wide ball of gas?”
Sharpening can invent. Deconvolution is an inverse problem, and inverse problems amplify noise into structure unless held back deliberately; push a wavelet slider — a sharpening control that boosts contrast at a chosen scale — far enough and you get ringing at the limb, haloes around moons, and belt edges crisper than anything the atmosphere delivered. Over-processed amateur images are full of exactly this, and two people working the same raw capture routinely produce visibly different planets. How many frames to keep, how hard to sharpen, what to do about colour — the operator’s taste is in the result, and “it came out of image-processing software” is a fair thing to want explained.
The case for a heliocentric, moving Earth rests on where planets are, and when — and a position needs only a dot.
| result | what it was measured from | detail required |
|---|---|---|
| Retrograde motion of Mars | naked-eye positions, recorded for millennia | none — no optics at all |
| Kepler’s laws | Tycho’s naked-eye positional catalogue | none — predates the telescope |
| Speed of light, Rømer 1676 | timings of Jovian moon eclipses | none — a stopwatch on a disappearance |
| Aberration of starlight, Bradley 1728 | stellar positions to tens of arcseconds | none — stars are points |
| Neptune, Le Verrier 1846 | residuals in Uranus’s measured positions | none — see below |
| Mercury’s anomalous precession | transit timings and positions | none — about 43″ per century |
Every one of these predates photography, let alone stacking software.
One thing optics does add to the positional case, and it is fair to say so: spin. Cassini timed a spot across Jupiter’s disc in 1665 and had the rotation at about 9 h 56 min; by the nineteenth century the timings were good enough to show the equatorial belts lapping the rest of the planet by five minutes a rotation, which is the first evidence that the visible surface is weather, not ground. That needs a marking, not fine detail — the Red Spot is a fifth of the disc across — and it needs a clock. The number it produced feeds straight back into the positional physics: rotation plus the measured flattening gives how mass is distributed inside, and the interior rotation timed from its radio bursts since the 1960s agrees with what the clouds showed Cassini to within a few minutes.
And the moons the chapter itself points to. The four Galilean satellites are the best positional laboratory a small telescope has: Galileo watched them change places night by night in 1610; their eclipses in Jupiter’s shadow, their transits, and the shadows they throw on the disc — the very shadows the chapter argues about at pp. 160–161 — are published years ahead to the minute and timed by amateurs with a stopwatch; and their orbits are what weigh the planet. A moon a second of arc across is a dot in any telescope. What carries the argument is when the dot goes out, and a dot cannot be sharpened into anything.
Neptune is the case that settles it. It was calculated from the discrepancy between where Uranus was predicted to be and where it was measured to be. Le Verrier published a position; Galle pointed a telescope at it on the evening of 23 September 1846 and found the planet about one degree away. Nobody could see anything on it: no feature at all was recorded on Neptune until methane-band CCD imaging from the ground in 1979, and its weather was first resolved by Voyager 2 in 1989. The standard objection is that Le Verrier was lucky — his predicted orbit was too large and his mass too great, and the planet sat near the place he named partly because of where it happened to be in its orbit that decade. Fair, about the orbital elements. But what the Uranus residuals constrained well was the direction of the unseen mass at that epoch, and direction is what was predicted and found. A wrong orbit that still puts a telescope within a degree of an undiscovered planet is evidence that the pull was real, and says nothing about pictures, because there were none.
Apparent sizes on the evening of Dury’s eight-planet photograph, 22 February 2025:
| planet | distance | apparent disc |
|---|---|---|
| Venus | 0.38 AU (Earth–Sun distances) | 44.3″ |
| Jupiter | 4.88 AU | 40.4″ |
| Saturn | 10.56 AU | 15.7″ |
| Mars | 0.81 AU | 11.5″ |
| Mercury | 1.25 AU | 5.4″ |
| Uranus | 19.71 AU | 3.6″ |
| Neptune | 30.79 AU | 2.2″ |
Uranus and Neptune are at or below the one-to-four-arcsecond blur the sky itself imposes — barely more than points from the ground, through any telescope, however processed.
Position is also a much weaker thing to ask of an image than detail: resolving a feature means separating two close points, which seeing destroys; locating an object means finding the centre of its light, which averaging helps. And an astrometric frame — one exposed to measure positions — carries its own calibration — the field stars in the same exposure have known catalogue positions and fix the scale, orientation and distortion of that image. Nothing of the sort exists for a wavelet-sharpened disc, which is why the objection at pp. 155–157 has force there and none here. The book’s own two tests run on positions, not pictures: the eight-planet challenge at pp. 162–163 asks whether a simulation reproduces the placement of the planets, and the Jupiter argument at pp. 158–161 turns on where a shadow sits relative to a moon and when it moves. The imaging critique and the tests it is meant to support are not measuring the same thing.
There is a second channel the book’s objection cannot touch, because it does not run through a camera: these bodies exert forces we can measure, and some of the measurements are not made by looking at the sky.
Mercury’s orbit turns, and mostly the other planets turn it. Mercury’s perihelion (the point of its orbit nearest the Sun) advances by about 575″ per century against a fixed frame. The famous Einstein residual is 43″; the other 532″, some 92 per cent of the whole effect, is simply the other planets pulling on Mercury, computed from their masses and positions and agreeing with what is observed. Venus and Jupiter do most of it.
Venus and Jupiter are written into rock. The largest-amplitude term in the variation of Earth’s orbital eccentricity is the g2 − g5 term — the difference between the rates at which the orbits of Venus and Jupiter precess. Its period is about 405,000 years, it drives climate through insolation (the sunlight a latitude receives), and it is recorded in sediment: the lake beds of the Newark and Hartford basins, the Chinle Formation at Petrified Forest, Japanese pelagic ribbon cherts, the Early Jurassic marine sequences of the Bristol Channel. Shown stable from roughly 215 to 202 million years ago in the Newark–Hartford cores, and further back by the Chinle correlation, it is now a calibration clock for geological time — a “geological orrery” that constrains the planets’ past motions from strata.
Jupiter weighed with a neutron star. Millisecond pulsars are clocks; timing one means converting arrival times to the solar system’s centre of mass, and a wrong planetary mass shows up as a wobble in the residuals at that planet’s orbital period. From four pulsars the Jovian system mass comes out at 9.547921(2)×10−4 solar masses — about four times better than the Pioneer and Voyager flyby values, and within a factor of twenty of what Galileo achieved in orbit.
Three limits. These effects are secular, accumulating over centuries and hundreds of millennia; nothing here says Jupiter influences a Tuesday. They are inferences inside a gravitational model, not proofs of it; what they add is channels that share no instrument or pipeline. And the sedimentary link runs through climate — orbit to insolation to lake level to lithology — each link with its own uncertainty; the 405,000-year signal is robust enough to serve as a metronome, but it is not a direct measurement of Jupiter.
The chapter’s question is what the planets are, and it looks for the answer in pictures. Most of what is known about Jupiter’s nature came from somewhere else: from timing its moons, from spreading its light into a spectrum, from measuring heat and radio waves the eye cannot see, and from watching a star go behind it. None of those steps sharpens an image. Set aside everything a spacecraft has measured on the spot and this is the answer sheet as it stood from the ground and from orbit around Earth.
| when | the measurement | what it says Jupiter is |
|---|---|---|
| 1610 → 1687 | Galileo times the four moons; Newton applies Kepler’s third law to Callisto’s orbit in the Principia | Its mass: 1/1,067 of the Sun by Newton’s figure, 1/1,047 today — 318 Earths. A dot and a clock, no picture. |
| 1664–65 | Hooke reports a spot; Cassini times it across the disc at about 9 h 56 min, and sees the disc visibly flattened — twenty years before Newton explains why | Its spin and shape: 6.5% oblate, the fastest-spinning planet. Mass and size together give the density, 1.33 g/cm³ — a quarter of Earth’s, and Newton derived it in the same proposition. Whatever it is, it is not rock. |
| 1932 | Rupert Wildt matches the dark bands in Jupiter’s spectrum to laboratory methane and ammonia | What is in its air: CH4 and NH3, among the first molecules identified on another planet — the same year Adams and Dunham found carbon dioxide on Venus. The bands themselves had been seen since the 1860s; Wildt’s step was naming them. A spectrum is a photograph of composition, and it is unsharpened by construction. |
| 1955 | Burke and Franklin pick up radio bursts from Jupiter at 22 MHz by accident; decimetric emission follows in 1959 | It has a magnetic field and radiation belts, more than ten times Earth’s field; by the 1960s the bursts’ own period (System III) gave the rotation of the interior, not the clouds. |
| 1960 | Kiess, Corliss and Kiess detect the faint quadrupole lines of molecular hydrogen | It is mostly hydrogen, as its density had already implied; helium, invisible in the optical, is inferred from how the hydrogen lines are shaped and later measured at about one molecule in seven, a quarter by mass. |
| 1966–69 | Frank Low and colleagues measure Jupiter at 8–14 µm from the ground, then from a Learjet at 15 km with a broadband 1.5–350 µm bolometer | How hot it is, and that it makes its own heat: cloud tops near 125–135 K, and by the 1969 measurement nearly three times as much energy radiated as sunlight delivers — since revised to about 1.7 times, which is still its own heat. It is still cooling from its formation. |
| 1971 | Jupiter passes in front of the star β Scorpii; the star’s fading is timed from several sites | The temperature and scale height of the upper atmosphere, from how fast the starlight dims — a hydrogen–helium atmosphere at roughly 150–200 K, measured with a photometer on a point of light — this page’s whole thesis in one row. |
| 1979 | Peale, Cassen and Reynolds compute the tidal heating of Io from the Laplace resonance of the inner moons | A prediction about a moon: enough heat to melt Io’s interior and drive volcanoes — published days before a spacecraft photographed the first plume. Gravity said it first. |
| 1980s– | Interferometers map Jupiter’s thermal radio emission at centimetre wavelengths; the VLA in particular | What lies under the clouds: ammonia’s distribution and the temperature tens of kilometres below the visible deck, from wavelengths that see through it. |
| 1994 | Comet Shoemaker–Levy 9 hits Jupiter; the plumes are watched spectroscopically from the ground and by Hubble | What comes up from below: sulphur compounds, carbon monoxide, water — the deep atmosphere sampled by an impact, on a schedule announced a year ahead. |
Every entry is a dot, a clock, a spectrum, a thermometer or a radio receiver. The rotation, the mass, the density, the gases, the temperature, the internal heat, the magnetic field, the layer below the clouds: the answer to “what are these luminaries” was substantially written between 1687 and 1971, and the pipeline the book disputes contributed nothing to it. What sharpened imaging adds is weather.
The other side of this deserves saying. Every line in the table is an inference through physics — Kepler’s law for the mass, laboratory spectra for the gases, black-body radiation for the temperature — and a reader who rejects the physics rejects the inference. But that is a different objection from the chapter’s. The chapter says the pictures are processed and so the planets are unknown. The pictures are processed; the planets were known before the pictures were.
The objection also contains a false assumption: that the processed amateur image is the thing our knowledge of these planets rests on. Instruments further up the ladder produce better pictures without the disputed step at all.
| instrument | θ at 550 nm | elements across Jupiter | how it beats the atmosphere |
|---|---|---|---|
| 60 mm | 2.31″ | 18 | it need not — the aperture is coarser than the seeing |
| 100 mm (4 in) | 1.38″ | 29 | lucky imaging and stacking |
| 200 mm (8 in) | 0.69″ | 58 | lucky imaging and stacking |
| 356 mm (14 in) | 0.389″ | 104 | lucky imaging and stacking |
| 508 mm (20 in) | 0.272″ | 148 | lucky imaging and stacking |
| Pic du Midi T1M, 1.05 m | 0.132″ | 307 | lucky imaging and stacking |
| Hubble, 2.4 m | 0.058″ | 701 | nothing — it is above the atmosphere |
| VLT, 8.2 m | 0.017″ | 2,395 | adaptive optics — hardware, not software |
| spacecraft in situ | kilometres per pixel | tens of thousands | no atmosphere and no distance |
Across Neptune’s 2.2″ disc the same apertures give 1.0 elements at 60 mm, 1.6 at 100 mm, 3.2 at 200 mm, 5.7 at 356 mm (taking 0.39″) and 38.5 for Hubble. Seeing is 1–4″, so above about 100 mm every single frame is seeing-limited; stacking is the route to the resolution the instrument already has.
The disputed technique runs continuously from a garden telescope to a professional observatory. The 1.05 m telescope at the Pic du Midi images planets by capturing thousands of frames, keeping the sharpest and stacking them — the pipeline the book calls “how to manipulate a photo” — under formal professional–amateur collaboration. Then come two rungs that do not need it. Hubble matters most: above the atmosphere there is no seeing, a single exposure is already at the diffraction limit, and it resolves about seven times finer than a good fourteen-inch stack and twice as fine as the Pic du Midi metre. The VLT corrects the wavefront in hardware, a different mechanism with different failure modes.
The professional images are processed too — Hubble frames are calibrated, drizzled (combined onto a finer grid from several offset exposures), composited and stretched — so there is no unprocessed image anywhere on the ladder. What matters is independent pipelines with unrelated failure modes converging on the same structure: the step the book disputes, selecting sharp frames through turbulence and sharpening the result, is absent from the Hubble pipeline and from a flyby, so an artefact of it has no route into either. Stacking is a booster, not a source.
A simulation, and labelled as one. The target is a synthetic phantom — a banded field beside a ladder of line pairs at 1.6, 0.8, 0.4 and 0.2 arcseconds — so nothing real can leak in. Each frame is that phantom seen through the aperture’s diffraction and a randomly drawn moment of seeing, then stacked and deconvolved the way an amateur would (method notes). The test: if sharpening manufactured detail, the detail would not care how big the telescope was.
The code is at stacking_demo.py and stacking_figure.py, seeded, and runs in about twenty seconds.
A simulation shows what the mechanism can do, not what a working astrophotographer’s capture does, so we asked one. Christopher Go, who images Jupiter from Cebu with a 356 mm Celestron C14 and whose work appears in the professional literature, sent a complete raw capture with permission to use it, and a sentence worth more than the file:
“I really don’t have a single capture because we actually capture videos of planets that we process.”
The unit of planetary imaging is a video, and the picture is what you compute from it; asking for the raw photograph is asking for a thing that was never made. What arrived: 3,215 frames at 107 per second — thirty seconds of Jupiter on 22 July 2022 at 20:41 UT, raw sensor data straight off the camera. Our own pipeline: register every frame against a fixed reference, average — no commercial software, no wavelet sliders, no deconvolution. The file checks out as the object, date and instrument stated (method notes).
Eyes are poor judges of this, so we measured the power at each spatial scale, single frame against stack.
That is the answer to “Image stacking + Deconvolution = Reality?”, measured rather than argued, on a working amateur’s own data. One limit: the seeing was unusually steady — sharpest and worst frames differed by only 7% on our metric — so frame selection contributed almost nothing and averaging did the work.
One capture can also be walked down the ladder: impose on each of Go’s frames the diffraction limit and reduced light grasp of a smaller mirror, then stack as before. Only the telescope is hypothetical, and only in the first three columns.
Mostly yes, for checkable reasons.
The chapter opens, at p. 154, by recommending a video to anyone who has never seen the planets first hand. The better recommendation is an eyepiece. A 60 mm telescope, the first row of the ladder table, resolves 18 elements across Jupiter’s 40″ disc with no camera and no software; the two dark equatorial belts are each several of those elements wide and are visible live, with the four Galilean moons and the rings of Saturn. “Jupiter 4.0” is a sharper version of a thing anyone with a small refractor can see from a back garden.
Simulation (stacking_demo.py): per frame, aperture diffraction at 550 nm, a seeing draw around a 2.5″ median, tip-tilt shift, photon noise; four hundred frames per aperture; the sharpest five per cent registered, averaged, then deconvolved. Recovered contrast at the 1.6″ rung is read against the phantom’s true 0.224.
Go capture (go_capture_stack.py): 3,215 frames, 720×620, eight-bit, raw RGGB sensor data; demosaic, register by phase correlation against a fixed reference, average. Provenance check: the planet measures 501 pixels across and the ephemeris gives Jupiter an apparent diameter of 43.82″ on 22 July 2022, so the image scale is 0.0875″ per pixel, consistent with the object, date and instrument stated. Power spectra are from an identical patch of the disc in a single frame and in the full stack; the diffraction line is at 0.389″ for 356 mm at 550 nm.
Ladder-down figure. Each frame is given the extra blur of a 102, 150 or 250 mm aperture (the quadrature difference between that aperture’s diffraction limit and the C14’s) and its noise is raised so that per-frame signal-to-noise falls with collecting area, the native noise being measured from the difference of two registered frames; 1,200 frames per column are then registered and averaged. The 102 mm limit in the caption is 1.36″.
2022-07-22-2041_2-CG-L-18.avi — 3,215 frames, Celestron C14, courtesy of Christopher Go, used with his permission. Our processing code accompanies this page in the repository.