Deep-sky session log · iPhone & iPad · Runs offline
The hours
add up.
A deep-sky image is never taken in one go. It is assembled, one clear night at a time, across weeks of waiting on the weather. DarkSync gathers those scattered nights into one archive that grows with you — so what you have collected on a target stops being something you try to remember.
Season archive · loading
Each square is one night. Filled squares carried data.
More than a notebook
A page per target
Every project holds its own page, and each session you log feeds straight into it. Open the app before you set up and you know exactly where to point the mount. Open it on the way in and half a minute of tapping puts the night on record permanently.
It has an opinion
DarkSync tells you when a target has stopped paying back the hours you feed it, so clear nights stop going into something that was already finished three sessions ago.
Catches the quiet errors
The mistakes that ruin a stack rarely announce themselves. They surface months later at the computer, with all that data and no clean way to rescue it. DarkSync raises them the same night, while the rig is still out and the fix takes a minute.
- M31 Andromeda 14 sessions 22.4 hours Diminishing returns
- NGC 7000 North America 6 sessions 9.1 hours No darks · 2 nights
- NGC 6960 Western Veil 3 sessions 4.8 hours Keep collecting
Load the sample archive and walk through a whole season before you record a single frame of your own. Then start project one.
Your archive never leaves the device
In effect from 26 July 2026 · applies to the DarkSync app for iPhone and iPad
In one paragraphDarkSync holds no account for you, talks to no server, and gathers no information of any kind. Everything you enter stays in the app on your own hardware. There is no paywall standing between you and your own hours, and no analytics or advertising code anywhere in the build.
What is gathered Nothing at all. The app has no registration step and no profile. It never asks for a name, an email address, a phone number or a date of birth, it does not look up where you are, and it does not read device or advertising identifiers.
Where the archive sits Projects, sessions, integration times, equipment profiles, sky conditions and written notes are saved into the app's own store on your iPhone or iPad. No account exists for them to sync to and no machine of ours ever receives them. If you asked us for a copy of your archive, we would have no way to produce one.
Built with the radio off Running totals, diminishing-return warnings and session checks are all worked out on the hardware in your hand, from figures you typed in yourself. Nothing is sent anywhere, for the simple reason that the app contains no path to send it.
Exporting and sharing When you export a project or pass a session summary to another app, iOS's own share sheet carries it out, and only once you have asked for it. From that moment the file belongs to wherever you sent it, and that destination's rules apply rather than ours.
Nothing embedded There is no measurement kit, no advertising library, no crash reporter and no tracking pixel inside DarkSync. Nobody is buying your attention here, so there is nobody to hand anything to.
Younger users Because no information travels from any user to us, none travels from a child under 13 either. There is no stored record for COPPA or its equivalents elsewhere to reach.
What you can undo Any project, session or note can be rewritten or thrown out from inside the app. Deleting DarkSync from the device takes its archive with it, and we keep no copy to restore from. If you use Apple's encrypted device or iCloud backups, your archive may travel inside them — those backups answer to you and to Apple's terms, not to us.
If this changes Should a later version of the app alter anything described above, this page is rewritten before that version ships and carries a fresh date at the top.
Asking about it Anything unclear here can go to stasmerkulov748@gmail.com.
Clear skies are rare. Mail is easy.
- Developer
- Lindsay Harper
- Reply time
- Usually one to two days.
- Worth sending
- Bugs, a catalogue object the app misses, a check it should be making and isn't, or a note about how you run your own sessions.