Start with your equipment
Your sensor, optic, and mosaic define what a satisfying frame looks like.
The night, made legible
Choose a target worth staying up for.
Ephemis turns your rig, your horizon, darkness, and the Moon into a ranked plan for the night. Every calculation happens on your device.
16,800
deep-sky objects
ready offline
ready offline
5 min
visibility samples
through the night
through the night
3
native platforms
iPhone · iPad · Mac
iPhone · iPad · Mac
0
accounts · ads
or signal required
or signal required
A planner that knows your sky
Not another list of things to image.
Most astronomy apps tell you what is overhead. Ephemis makes the harder call: which object deserves your limited dark time tonight.
Read the whole night
Darkness, altitude, your local horizon, and meridian timing are sampled together.
Let the Moon have its say
A moving Moon track weighs every moment, not just a single phase value.
Built for clear-sky decisions
Less searching. More collecting photons.
Everything that changes the answer is considered before you power on the mount.
Framing-aware ranking
Targets are scored on how well they fill your rig's field of view—never too big or too small for your optic.
Moon avoidance
Broadband and narrowband-aware scoring follows the Moon across the entire night and shows safe imaging hours.
Real darkness windows
Choose astronomical, nautical, or civil twilight and see each target's genuinely usable hours.
Full-night altitude charts
Altitude, transit, meridian flip, horizon limits, usable segments, and the Moon share one calm chart.
My Targets projects
Save a plan, set goal hours, log sessions, and compare tonight's visibility across your wishlist.
FITS and XISF session import
On Mac, import capture headers into project sessions without reading heavy pixel data or counting masters as exposure.
Fully offline
NGC/IC, Sharpless, Barnard, vdB, LBN, and LDN are bundled. Planning still works at a remote dark site.
Private iCloud sync
When iCloud is available, rigs, sites, and projects follow you through your private CloudKit database.
Plan on every screen
One workspace, from field to desk.
Ephemis feels at home on iPhone, iPad, and Mac.
Private by architecture
Your sky plan stays yours.
The catalog ships with Ephemis and the calculations run on your device. There is no Ephemis account, analytics, advertising, or tracking.
✓ Works without a network connection
✓ No personal data collected by Ephemis
✓ Optional sync through your private iCloud
Privacy status
ON DEVICE
0trackers
0ads
0Ephemis accounts
100%offline planning
Your next clear night
Spend it collecting photons, not choosing a target.
Free · no Ephemis account · no ads.
Download on the App Store