AstroFinish vs AstroPile

AstroFinish is a darkroom for astrophotography on iPhone. It is built for the shots that come off smart telescopes, backyard rigs, and late-night moon sessions: the ones that are almost there, but need a cleaner sky and a better finish. Start fast with Auto Astro Polish, Deep Sky, Moon Sharp, and other built-in looks. Or dial it in by hand with controls made for space photos, including black point, glow cleanup, nebula reveal, galaxy detail, denoise, star reduction, and moon sharpening. Import from Photos or Files, work with JPEG, PNG, HEIC, TIFF, RAW-style images, and FITS sessions, then export finished images or shareable before/after cards. Batch Finish helps run one look across a queue when you came home with more than one keeper. AstroFinish stays local. No account. No cloud upload. No tracking SDKs. Your captures stay on your iPhone unless you choose to share or save them. Built for: Smart telescope captures Deep-sky photos, nebulae, galaxies, star fields, and moon shots Quick fixes when the sky glow gets rude Manual finishing when you want the last word FITS reveal and stack workflows Local exports, share sheets, and before/after cards AstroFinish is for people who would rather be outside collecting photons than fighting a desktop editor at 1 a.m.

One phone photo of the night sky is mostly noise. Stack a dozen shots of the same scene and the noise averages away while the faint detail stays — that is what astrophotographers call stacking. AstroPile does it on your phone, entirely offline: no network permission, and no photo is ever uploaded. WHAT MAKES IT DIFFERENT IS THAT IT TELLS YOU WHAT HAPPENED. Most stackers hand you one picture. If it came out smeared, you have no idea which frame ruined it. AstroPile gives every frame a report card: • how many stars were detected • how many matched the reference frame • the alignment residual, in pixels • a 0–100 quality score Frames that could not be aligned say why — too few stars, too bright, no matching star pattern, residual too large, different pixel size — plus one line on what to change. Untick it and stack again. HOW IT WORKS 1. Pick two or more shots of the same scene 2. Choose the reference frame (the first one by default) 3. Start stacking — you can stop at any point 4. Drag black point, brightness and saturation; the preview updates live 5. Save to Photos or Share — the export is full resolution HOW IT ALIGNS Not by corner detection: stars look identical to each other, so feature matching does not work on a star field. AstroPile matches asterisms — the shape of the triangle each star forms with its neighbours — then uses RANSAC to throw out the false pairs and solves for shift, rotation and scale. This is the standard approach for registering star fields with no WCS information. DETAILS THAT MATTER • Reads EXIF on import and flags frames shot with different exposure settings than the rest • Frames with a different pixel size are marked in red instead of quietly ruining the stack • Combines in horizontal bands, so even a few dozen full-resolution frames will not exhaust memory • Scratch files are deleted when the run ends, and swept again on the next launch FREE Up to 6 frames per stack, mean stacking, full-resolution export, and the full per-frame alignment report. No ads, no watermark, no account. ASTROPILE PRO (a one-time purchase, not a subscription) • Up to 32 frames per stack • Median stacking — aircraft, satellite trails and hot pixels drop out on their own • Remembers your stacking mode and working resolution PRIVACY The app requests no network permission and contains no analytics or advertising SDK. Photos are read and processed on this device only; the finished picture leaves the app only when you save or share it. CREDITS Star-field registration follows astroalign (MIT, © 2016 Martin Beroiz), frame stacking follows OpenSkyStacker (MIT, © 2017 Benjamin Schubert), and the star-sharpness check follows the published design of astra_lite (MIT, © 2023 Denis Artyomov). This app is an independent Dart implementation and copies none of their code.