Your deep sky imaging archive — cataloged, visualized, and searchable. Native on Apple Silicon.
$34.99, one-time purchase. Requires macOS 14 or later.
Your imaging archive deserves better than a folder of folders.
After years of imaging, your data is scattered across drives, naming conventions have drifted, and you can't remember which equipment you used for that one session two years ago. Finding a specific sub from a specific night means clicking through folder after folder, hoping your file names are descriptive enough. If you shoot with a smart telescope the problem arrives faster: a Seestar or a DWARF can fill a drive in a single season, and the folders it leaves behind tell you very little about what you actually captured.
Meridian is a native macOS deep sky archive manager from Mac Observatory, built for exactly this problem. Point it at your imaging folders and it reads every FITS and XISF header, identifies each target by its sky coordinates across 20 astronomical catalogs, groups your frames into sessions, and builds a searchable, visual catalog of everything you have ever shot.
You don't have to reorganize your whole archive first. Meridian reads whatever structure you already have, and it never modifies your files: no moving, no renaming, no rewriting headers. It only reads them. There is one organizing decision that genuinely matters, though, and it is worth two minutes before you scan. That is the next section.
One folder per object. That is the structure Meridian needs.
Meridian identifies your targets from the coordinates in your headers, but it uses your folders to decide which frames belong together. It steps over any folder named for a year, then treats the next folder down as a single target and reads everything beneath it. So that folder needs to be an object.
Get that one level right and everything else is yours to arrange however you like.
Don't sort by equipment or object type above your objects.
This is the most common way an archive confuses Meridian, and it fails quietly. In 2026/Redcat/M90/ the target becomes "Redcat", and every object you ever shot with that scope merges into one entry. Same with 2026/Galaxies/M90/. If you want to group by rig or by type, do it above the year rather than below it. You don't need equipment folders anyway: Meridian already tracks your gear from the headers and lets you filter by it.
What is flexible inside an object folder
Almost everything. Subfolder names are invisible to Meridian, so Light, Subs, Raw, or one folder per filter all work identically, at any depth. Calibration masters can live in a Calibration folder or sit loose beside your frames. Finished images belong in the object folder, where Meridian associates them back to the frames that produced them. Sessions, filters, exposure times, and equipment all come from the headers rather than from the layout.
If an object folder does end up holding frames aimed at very different parts of the sky, Meridian warns you instead of guessing. It never splits a folder, never renames anything, and never modifies a file. For a fuller walk through archive organization, see my guide to organizing an astrophotography data library.
Your equipment comes from your headers.
Meridian builds your entire equipment list out of what your capture software wrote into the FITS headers: telescope, camera, focal length, and pixel size. No manual entry, no setup screen. It also tolerates the small stuff, so a rig that reports 754 mm one night and 756 mm the next stays a single profile instead of fragmenting into three.
Fill it in once
Enter your telescope and camera names in your capture software and they flow into Meridian automatically, for every session from then on.
Got it wrong? Fix it after
Rename the scope or the camera on any data set, and choose whether the change applies everywhere that profile is used or only to that one session.
Wrote nothing at all?
If neither the telescope nor the camera made it into the headers, there is nothing for Meridian to attach a name to and that session stays unattributed. This is why step one is worth five minutes tonight.
Object Recognition
41,730 objects across 20 catalogs, resolved automatically.
Meridian identifies each target from the pointing coordinates in your FITS and XISF headers, then resolves it against a built-in database spanning 20 astronomical catalogs. Because it works from where the telescope was actually aimed rather than trusting the name someone typed, it finds the right object even when the header is wrong, blank, or full of a previous owner's shorthand.
Tier 1: Core Catalogs
Tier 2: Extended Catalogs
Tier 3: Advanced Catalogs
M42 = NGC 1976 = Sh2-281 = LBN 974. Meridian knows they are all the same object and groups your data accordingly.
Every target you've ever shot. Everything about it in one place.
Meridian organizes your archive by astronomical object, not by folder, not by date, not by file name. The Catalog view gives every target a dedicated page: your finished image as the hero, total integration time, a per-filter breakdown, the full session history, and every equipment setup you have used on it.
Finished images get associated back to the frames that produced them, so the picture you posted and the eleven nights of data behind it stay connected even when they live in different folders on different drives.
Sort by integration time, filter count, or date. Filter by catalog, object type, constellation, or equipment. Press Command-K to jump to any target instantly. Your archive becomes a living reference of everything you have captured.
Know what to shoot tonight, before you set up.
The Wish List view turns your archive into a planning tool. Build a target list, check altitude and transit times for your location, compare field of view against your equipment, and plan sessions across multiple imaging sites. Because Meridian already knows what you have shot, it also knows what you are short on: the targets you have started and never finished are right there next to the ones you have never tried.
Visibility Data
Altitude, azimuth, transit time, and hours above horizon for every target on your wish list.
FOV Comparison
See how targets fit your sensor and telescope combination before committing to a session.
Multi-Site
Save multiple imaging locations and switch between them for accurate visibility calculations.
Wish List
Build and maintain a list of targets you want to image, with visibility recalculated for the current night.
Built for the Mac from the ground up.
Meridian is written entirely in Swift and SwiftUI, and ships as a universal binary that runs natively on both Apple Silicon and Intel. It uses SwiftData for its local database and Metal for GPU-accelerated thumbnail rendering. It is not a port, not an Electron wrapper, not a web app in a frame. It is a real Mac app, built with Apple's own frameworks and nothing else.
Full dark mode support. Keyboard shortcuts for everything. A Quick Look extension that previews FITS and XISF files directly in Finder, even when Meridian is not running, and Spotlight integration that makes your archive searchable from anywhere in macOS. Your imaging data stops being an opaque pile of files and becomes something the rest of your Mac can see.
What Meridian Can Do
One app. Every feature included. Zero file modifications.
Statistics Dashboard
Eight sections of imaging analytics: activity timelines, filter usage, sky coverage, equipment stats, and more.
Interactive Sky Map
Powered by Aladin Lite. See every target you have imaged plotted on an interactive sky survey.
Source File Triage
See exactly which files were skipped and why, and overrule the decision per file or per folder.
Equipment View
Every telescope, camera, and filter pulled automatically from FITS headers, with the targets shot on each.
Star Extraction & Seeing
HFR and FWHM analysis across your subs. Track seeing conditions and focus quality over time.
Session Grouping
Loose frames are grouped into the nights they were shot, so integration time adds up on its own.
Live File Watching
FSEvents monitoring. New files appear in your catalog automatically as they are written to disk.
Hybrid Plate Solving
Solves locally with ASTAP for frames missing coordinates. Astrometry.net cloud rescue is opt-in.
Final Image Association
Your finished picture stays linked to the frames behind it, even across different folders and drives.
Auto-Stretched Thumbnails
Midtone Transfer Function stretch on every thumbnail. See your data, not black rectangles.
Quick Look & Spotlight
Preview FITS and XISF in Finder with spacebar, and search your archive from anywhere in macOS.
Strictly Read-Only
Meridian never writes to, moves, renames, or modifies your imaging files. Your data stays exactly where it is.
Compatibility
File Formats
Works With
Requirements
Pricing
One price. Every feature.
No subscriptions. No tiers. Buy once, own it forever.
Meridian
$34.99
One-time purchase. Every feature included.
- ✓ Folder scanning, indexing, and cataloging
- ✓ Object resolution across 20 catalogs
- ✓ Auto-stretched MTF thumbnails
- ✓ Quick Look extension for FITS and XISF
- ✓ Live file watching with FSEvents
- ✓ Source file triage and reclassification
- ✓ Interactive sky map (Aladin Lite)
- ✓ Wish list and visibility planning
- ✓ Statistics dashboard
- ✓ Star extraction and seeing analysis
- ✓ Equipment tracking from FITS headers
- ✓ Final image association
- ✓ Local plate solving with optional cloud rescue
- ✓ Spotlight integration and multi-site support
Includes Family Sharing for up to six people. No subscription, no in-app purchases.
Mac Observatory Suite
Built for the Mac. Built for Astronomers.
Native macOS apps filling the gaps the astronomy community has been waiting for.
The Observing Workflow Look Up → Capture → Process → Archive
It starts with Transit: live conditions and tonight's events tell you whether the sky is worth it. From there the planetary chain takes over, with Laminar capturing and Strata stacking and sharpening on the GPU. Meridian covers the other half of the hobby, turning a deep sky imaging archive into a catalog you can actually search.
Guiding Diagnostics Free & Open Source
Swift & SwiftUI · Apple Silicon Native · Metal GPU · No Subscriptions
Common questions about cataloging and managing a deep sky imaging archive on macOS.