AkastroidThe Moon
Craters to the terminator,without four programs.
Drop in a lunar video or a folder of frames. Akastroid grades every one, keeps the sharpest, aligns the surface in pieces so the atmosphere's local warping comes out, and hands you six scales of sharpening that re-apply the instant you move them.
Free to try. Nothing is uploaded, and there is no account to create.
The Moon is bright, which changes everything
Nothing about lunar imaging is limited by how much light there is. The exposure is a fraction of a second, the contrast is enormous, and a single frame already shows craters. What ruins the picture is the atmosphere - a few kilometres of moving air that smears the detail differently in every frame, and differently in different parts of the same frame.
The answer is lucky imaging: record hundreds or thousands of very short frames, keep the ones the turbulence happened to leave sharp, align them, average them, and sharpen what comes out. It is the same approach used for the planets, and the Moon puts more strain on one part of it than any planet does, because the Moon is enormous.
Multi-point alignment matters more here than anywhere
A planet is a small disc; a lunar close-up fills the sensor. Over a field that wide the seeing is not one blur but many, and aligning the frames as a single rigid object gives you a sharp edge and a mushy middle - or a sharp middle and a smeared limb - because the misalignment averaged the detail away before the sharpening ever ran.
Akastroid tracks the surface on a grid of alignment points you can space yourself, and the points are placed where there is real structure rather than spread evenly over whatever happens to be in frame. Each point is ranked separately across the frames, so a region that was sharp in frame 40 contributes there even if the rest of that frame was soft.
Grading that is not fooled by noise
The obvious way to score a frame's sharpness - the energy in its finest detail - gets short exposures backwards, because the finest thing in a noisy frame is the noise. Score that way and the grainiest frames rise to the top of the list and into your stack.
What is measured instead is the structure at the scales lunar detail actually occupies, divided by the noise in that same frame. You set the percentage to keep, with a graph of the whole capture showing how the seeing moved while you were recording.
Detail below the pixel scale
Most lunar captures are undersampled - the optics resolve more than the sensor's pixels record. When the disc is small in the frame, the survivors are integrated onto a finer grid, which recovers detail from the sub-pixel shifts between frames rather than merely enlarging what was there. It is the difference between a bigger picture and a better one.
Mineral colour
The Moon is not grey. Titanium-rich maria are genuinely blue, the highlands genuinely warm, and the differences are a few per cent - well below the noise of any single frame and perfectly measurable in a stack of a few hundred. Once the stack exists, saturation takes those differences from technically present to visible, and every adjustment re-renders immediately because the expensive work was done once.
Atmospheric dispersion is corrected first, for the same reason it matters on a planet: a low Moon arrives with its colour channels displaced, and a mineral-colour treatment applied to a dispersed stack turns a real blue mare and a refraction artefact into the same thing.
Mosaics of the whole disc
At the focal length that resolves craters, the Moon does not fit in one frame. Shoot it in overlapping panels and Akastroid matches and blends them into a single image, so a full-disc portrait keeps the resolution of the close-ups it was made from.
What this replaces
The traditional lunar chain is a pre-processor, a stacker, a wavelet sharpener and sometimes a stitcher - four programs, all free, all Windows-first, each with its own conventions. Akastroid does the common path through them in one window, on a Mac as well as a PC, with the grading graph and the sharpening sliders on screen together so you can move between them without exporting anything.
If you would rather read about the photography than the software, the guide on photographing the Moon covers phases, exposure and why the terminator is worth waiting for.
The same application does the rest of the sky
Planets take the same lucky imaging path, the Sun has its own, and nebulae and galaxies the deep sky path. One application, one licence.
Can I stack a video of the Moon, or does it need stills?
Either. A SER or AVI capture takes the lucky imaging path - every frame graded, the sharpest kept, aligned in pieces and averaged. A folder of stills works too. Video is better for a close-up at high magnification, where the seeing changes between one frame and the next; stills are fine for a whole disc through a short lens.
Why is my stacked Moon soft in the middle and sharp at the edge?
Because it was aligned as one rigid object. The atmosphere does not shift the Moon, it warps it - and across a field as wide as the lunar disc, the warping is measurably different from one crater to the next. Aligning on a grid of points across the surface takes that out before anything is averaged. It is the single setting that separates a soft lunar stack from a sharp one.
Can it bring out the mineral colours?
Yes. The colours are real - titanium-rich maria run blue, the highlands run warm - and they are in an ordinary colour camera's data, several per cent apart. Stacking is what makes them usable: the differences are far below the noise of a single frame and survive averaging. The saturation control then takes them from technically present to visible, and because the stack is already made, moving it re-renders immediately.
What about the terminator?
The terminator is where the detail is, and it is also the hardest part to expose - shadows an instant from black beside a lit crater rim. Frames are graded on the structure your capture actually holds rather than on raw contrast, so a frame is not favoured for being noisy, and highlight protection keeps a bright rim from clipping into a flat white edge while the shadow detail is stretched.
Do I need to crop the capture first?
No. The disc is found, the stack is cropped around it with generous margin, and the alignment points are placed where there is real detail rather than on empty sky. There is no separate pre-processing step and nothing to convert.
My Moon has a blue edge on one side and a red edge on the other.
That is atmospheric dispersion, and it happens whenever the Moon is low: the atmosphere refracts blue more than red, so the three colour channels arrive slightly displaced. Red and blue are realigned to green before sharpening. Done afterwards, the sharpening has already turned the fringes into something no alignment removes cleanly.
How long does it take?
A capture of a few hundred frames finishes in seconds, and the sharpening sliders re-apply instantly afterwards because changing them does not rebuild the stack. A capture of tens of thousands takes longer to grade, but the interactive part stays immediate.
Can it stitch a mosaic of the whole disc?
Yes. Panels shot at high magnification are matched and blended into one image, which is how a detailed full-disc Moon is made at a focal length that cannot fit it in a single frame.
Try it on tonight's Moon.
Free to try, no account, nothing uploaded. A few hundred frames finish in seconds.