Solar post-processing, in a browser tab
Ordinary sharpening cannot tell a fibril from a grain of noise, so turning it up buys you both. HeliosSharp reaches for the fibril alone, keeps a flat-field fix from touching the Sun, aims contrast at one width of structure, and stitches a folder of panels into one picture. Try it free on ten of your own frames and see what was already there.
US$49, once · ten images free to try first
Nothing to install · your file never leaves your machine
Twenty-two sections and two rooms of their own. The whole panel, in the order you work.
Every control on this page, all twenty-two sections and both rooms besides, was tuned on this imager's own solar frames. What's below is the whole panel, walked through in the order you actually work in it: five phases, each in the app's own order, with the fifteen sections that carry a picture of their own, fourteen of them a before and after, sitting inside the phase they belong to rather than pulled out to the front. The stitcher and the batch room come last of all, each a room of its own.
Pull the levels apart until there is something on screen to work on. Start here.
01 · Stretch phase
A stacked frame usually comes out flat, sitting in a narrow band of grey with nothing bright or dark enough to judge. The tone curve remaps which brightness reads as which shade: drag the black and white points inward and that narrow band spreads across the whole range, so there is finally a picture worth judging. Start here, since every later control is only showing you the frame through this curve.
Recover the detail the seeing took away, without lifting the grain with it.
02 · Sharpen phase
A stacked frame still carries fine grain, sitting at roughly the same size as fibrils and granulation, so sharpening later would lift the noise right along with the real detail. Noise Reduction clears that grain out first, before anything downstream gets a chance to amplify it. Run it on any capture that still looks grainy once you have stretched it, and keep the effect modest so texture survives.
03 · Sharpen phase
Every capture loses sharpness to your own seeing and optics, which smear a point of light into a small blur. Lucy-Richardson models that blur, then works backwards from it to recover the detail, the strongest recovery step in the chain and the slowest to run. It can also invent dark rings around bright, clipped highlights, which is what Prevent Ringing quietly watches for; here it has nothing to guard against.
04 · Sharpen phase
A frame can carry real detail and still look soft on screen, because nothing in it stands out sharply enough from what surrounds it. Unsharp Masking is the oldest fix: it raises contrast at one size of detail you choose, so edges and surface texture finally stand apart. One mask only covers one size well, so stack a second at a different width rather than splitting the difference, and switch on Adaptive to hit the disc hard while leaving the background and any prominences alone.
05 · Sharpen phase
A stacked frame holds detail at several sizes at once: fine granulation, mid-sized fibrils, and whole active regions, all sitting in the same pixels. Wavelet Layers splits it into those bands, so each size gets its own sharpen and its own noise cleanup instead of moving together. Bring up fine thread texture while leaving an active region untouched, or calm a noisy fine band without softening the big structures.
06 · Sharpen phase
Sharpen the whole frame and the fibrils, the filament and the grain all come up together, when you only wanted one of them. Structure Contrast measures how wide the structure through each pixel actually is, then adds contrast only near the width you choose. Lift fine threads while a filament sits still, or push the filament forward and leave the threads alone. You choose which, not the whole frame.
07 · Sharpen phase
Push ordinary sharpening hard enough to bring up a fibril, and every fleck of noise the same size rides along with it, because size alone cannot tell them apart. Fibril Enhance works by shape instead: it walks each ridge to see whether it goes anywhere, and only lifts where something held, so a round speck of noise has nothing to walk along. Run it last, once the rest is set, and add a second pass for structure the first misses.
08 · Sharpen phase
A frame can be sharp and correctly stretched and still read flat, with nothing in it standing far enough apart from its surroundings to give the picture any depth. Texture and Clarity round that off: Texture adds local contrast a few pixels across, giving granulation and fine threads more bite, while Clarity works across tens of pixels, on active regions and the overall shape of the disc. Both run in a Solar mode built to avoid haloing along the limb, rather than behaving like an ordinary photo editor.
Now you can see the frame, fix what the capture got wrong, and clear up what the sharpening left behind.
09 · Correct phase
An etalon and its cover glass can print a faint ripple of concentric rings across the frame, a fault of the optics rather than the Sun. Newton's Rings measures that pattern and subtracts it: raise Amount until the ripple stops drawing the eye. The rings circle a centre the optics choose, not the disc, so it often sits well outside the picture, as the Y of -320 above shows. A frame with no pattern comes back untouched, so it costs nothing to try.
10 · Correct phase
A stack can come out uneven for reasons that have nothing to do with the Sun: a bright corner from the flat field, a milky sky, a disc darker on one side than the other. Field Correction fixes exactly that, with one control for the sky, one for the disc and one for haze over the whole frame, since a capture can carry all three faults at once. It reports how uneven each is before you touch anything, and sharpness never moves while it works.
11 · Correct phase
The sky right outside the limb often comes back milky instead of black, especially with a prominence sitting in it, because the disc is throwing its own glow out across the frame. Scattered Light strips that glow back down to sky level rather than touching the prominence itself. A tilt adapter can add a harder edged version of the same thing, a faint out-of-focus copy of the limb thrown back onto the sensor and offset to one side, and that is the band in the picture here: it lifts out with the rest. Raise Strength until the sky goes flat and dark, and stop the moment a dark moat rings the limb; match Extent to how far the halo visibly reaches.
12 · Correct phase
A prominence often sits two or three stops darker than the disc beside it, and the disc itself dims toward the limb for real, so one exposure can't suit both. Limb & Prominences fits the limb, divides out that real edge dimming so detail there reads like detail at centre, then gives the disc and everything beyond it their own gain, so a faint prominence comes up without dragging the disc along. The sky gets its own sharpening, noise reduction and black point.
13 · Correct phase
Sharpening tends to add its own fine grain on top of whatever was already there, roughness the first noise reduction pass ran too early to ever see. Final Noise Reduction cleans that up once everything else is finished, smoothing what sharpening left behind without softening the fibrils it just brought out. Reach for it whenever a finished frame still looks rough up close, usually with a light touch.
Set the colour, then the levels, and finally the framing of the file you hand over.
14 · Finish phase
A monochrome disc says everything in one shade of grey, and getting a light-specific colour onto it normally means picking a ramp by hand, setting where black and white land on it, and doing the whole thing again on the next frame from the same rig. Spectral Mapping keeps that as one control instead: pick the light you shot in, set two points, and every later frame gets the same treatment without rebuilding the ramp from scratch. It only ever touches the screen and the PNG; the 16-bit TIFF stays monochrome underneath it.
15 · Finish phase
A finished monochrome disc is one shade of grey all over, so fine fur, fibril bundles and a filament look the same until you study the texture pixel by pixel. Structure Colour paints by what kind of structure is there instead: width chooses the hue, run length chooses how deep the colour goes, so noise stays yellow, fibrils come up orange, a filament goes red, one colour along its whole length. The four swatches are yours to change, and only the PNG carries it; the TIFF stays monochrome.
16 · Finish phase
An H-alpha frame comes out sharp corner to corner, which sounds like the goal and gives the eye nowhere to land: the active region you spent the session on reads no louder than the quiet surface beside it. Selective Focus softens everything outside a shape you place and leaves what's inside it untouched, the way a lens throws a background out of focus. Round holds a circle, Band holds a strip at any angle, so a whole side of the frame can stay sharp on its own. Reach for it last, once the picture is otherwise finished.
17 · Finish phase
A raw stack can sit well outside a usable range, too dark, too flat or too contrasty to judge properly. Gamma, contrast and brightness here get it roughly into shape in one quick pass, fast global moves rather than precise ones. Use it to get a frame into the right ballpark, then hand anything finer to the tone curve, which gives you far more control over exactly where the contrast lands.
18 · Finish phase
Rotate, flip or crop the frame here before anything else touches it, since every later control is measured against whatever frame you leave behind. A star diagonal can mirror a picture left to right, so flip until a feature you recognise lands on the correct side. Crop tight at this stage too: the slow stages that follow only process what is left, the cheapest speed-up in the whole chain.
19 · Finish phase
Post a finished disc anywhere and nobody can judge how big anything is, when it was shot, or which spot group is which, and a measurement you made yourself is a number with nothing tying it back to the picture. Marks puts that information on the picture: an Earth at true relative size, a scale bar, capture time, a north marker, NOAA's active region numbers, and a numbered chip for every measurement you keep, tied to the key. Kilometres and millionths of a hemisphere, on the exported PNG; the 16-bit TIFF stays clean.
20 · Finish phase
A finished treatment is only as good as what leaves the app. Export writes the 16-bit TIFF for anything you'll measure or work on again, the PNG for anything you'll show, and a settings sidecar for whatever you may want to load back later.
Your telescope, and how the app runs on this machine. Set the scale once per rig.
Setup phase
Calibrates the rig once, not every picture: it fits the disc's own radius in pixels and reads arcseconds per pixel off that, and every pixel-sized control on the panel starts from what it learns. It also says where detail stops in your capture, and that sharpening finer than that invents texture rather than recovering it.
Setup phase
Runs deconvolution and the sharpening stages on the graphics card instead of the processor, seconds down to a fraction of one, with the picture itself unchanged. Worth a look if a slider stops feeling immediate, or a driver misbehaves.
Not a step. A room of its own.
Nothing above assumes a mosaic. Point the stitcher at a folder of overlapping panels and it hands back one picture, which then drops straight back into the panel above, so every phase you've just walked through already applies to it.
A room of its own
Shoot a full disc close-up and you get a folder of overlapping panels, and lining them up by hand while matching sky brightness tile to tile is fiddly work that still leaves the joins showing. Point the stitcher at the folder instead: it checks the set will stitch before doing any work, lines up every overlapping pair of frames and builds one layout from the ones it trusts, blends every join and evens the sky across the whole picture. Below is one real run: ten panels, five minutes, one disc.
There's no before-and-after wipe here, because there's no single frame to put on the other side of one. What you get instead is two steps of the one run: the check, then the picture it built.
Not a step either. A room of its own.
A good session leaves you with a folder of frames rather than one. Get a single frame looking the way you want it, then point the batch room at the folder: every frame goes through that same treatment, and each picture is written out the moment it is finished rather than held back to the end.
A room of its own
Come back from a session with a folder of frames of the same target and the work in front of you is the same work over and over: open one, set it up, export it, start again. Done by hand no two quite match, because the sliders moved a little between frames. Hand the folder over instead and choose the recipe once, either the settings already in your panel or a preset you saved earlier. Every frame goes through that one recipe, colour included, and each finished picture is saved as soon as it is ready. The panel behind the room is out of reach while a run is going, so nothing can drift halfway through.
There's no before-and-after wipe here either, because a batch isn't one frame. What you get instead is two steps of the one run: the set and the recipe it will use, then the run itself.
And three more things in the app aren't sections at all, so they sit outside the twenty-two above:
Where it fits
Nothing changes about how you capture or stack; that half already works. Drag the finished stack onto this page, or point the stitcher at the folder your panels are already sitting in, and pick up from there.
SharpCap, FireCapture. Nothing changes here.
AutoStakkert!, Registax, AstroSurface. Nothing changes here either.
16-bit TIFF or FITS in, one frame or a folder of panels. It opens on your machine and is never uploaded anywhere.
16-bit TIFF or PNG out, plus a preset you can drop on the next frame or on a whole folder.
Trial and buying
The trial is the whole app, not a cut-down copy of it. Every tool works exactly as it does after you buy; only the count of images you can open is different.
Opening an image spends one of your ten. Re-opening the same file again is free, and a batch run counts each frame, but a picture stitched from a folder of panels counts as one.
Every tool is unlocked from the first image. Work each one as much as you like, export it as often as you like.
The app opens to an unlock screen and nothing else, with the buy link and a box for your key.
Clearing your browser does not reset the count. Type your email again, get a new sign-in code, and carry on where you left off.
Try it
That's the fastest way to judge any of this, faster than reading another paragraph. Ten images free, nothing to install, and your file never leaves the machine it's already on.
Already sure
US$49, once, no subscription.
Every update while it is sold, on up to three computers. Your key arrives in the Gumroad receipt email as soon as you buy.