You're probably wondering one of these

Yes, both editions (Standard and Pro) are distributed free of charge, with no time limit, no feature restrictions, and no account required. If the software is useful to you, a voluntary donation is possible via PayPal (link available in the software's Help tab and on the Contact page) — but nothing is ever asked in return.

The Pro edition adds everything related to onboard electronics and tides: multi-protocol GPS reception (serial, UDP, NMEA 2000, SignalK) with a built-in simulator, worldwide offline tides, a plotting sheet and world map, man overboard, full compass deviation, and a WMM cross-check. The core of the astronomical calculations (ephemerides, lines of position, route, error budget…) is identical in both editions. Full detail on the Specifications page.

Astra Vela Pro is a calculation and training aid, not a certified instrument. It does not replace official instruments and publications (nautical almanac, GNSS, onboard procedures), and the user remains solely responsible for the vessel's navigational decisions.

The software is currently at version 0.1.0: it's a very young piece of work, without an extended track record, and it may well contain early-life bugs.

Windows 10/11 (.exe installer), and Linux in three selectable formats: .AppImage (portable, any distribution), .deb (Debian/Ubuntu…) or .rpm (Fedora/openSUSE…).

Honestly, the author has not been able to test its installation on an .rpm-based distribution. The package is provided as-is; if you try it, feedback is welcome via the Contact page.

Four possible methods: NMEA 0183 serial port, UDP network (NMEA 0183 multiplexer), NMEA 2000 (fast-packet frames), or SignalK over WebSocket. A built-in GPS simulator lets you test each of these protocols without any connected hardware.

This is a classic conflict, and the AVP manual actually gives a precise hint about it: it explicitly notes that on certain handheld GPS units such as the GPSMAP 86i, a "mass storage mode?" prompt reappears on every USB connection, even when the interface is already set to NMEA/Spanner, and that you need to answer "No" every time. Installing BaseCamp and Garmin Express typically makes this worse, because both programs are designed to talk to the GPS in map/firmware-update mode (MTP or mass storage), not serial NMEA mode — and their drivers/background services tend to grab the port as soon as it's plugged in, before AVP gets a chance to open it.

Steps to follow, in order:

1. Check the interface setting on the GPSMAP 86i itself: Setup → System → Interface, and choose "Garmin Spanner" — this is the mode that creates the virtual COM port a third-party program can use over NMEA 0183 via USB ("NMEA In/Out" is for an actual RS-232 serial link, not the USB port). If the device has stayed on a different setting since BaseCamp/Express was installed, it will never present a COM port to AVP.
2. Every time you plug it in, answer "No" to the mass-storage-mode prompt on the GPS screen — a known behavior of this model, independently confirmed on Garmin forums for the same device generation (66i/86i), and documented in the AVP manual itself. An accidental "Yes" switches the device out of NMEA mode.
3. Fully close BaseCamp and Garmin Express before plugging in the GPS and launching AVP — not just minimizing the window. Garmin Express runs a background service that can automatically grab the device as soon as it detects a GPSMAP being plugged in (to offer an update). Disable automatic launch/background detection in its settings if the option exists, or temporarily stop its service in Windows Services while using AVP.
4. Check Windows Device Manager: after installing BaseCamp/Express, see whether the GPSMAP shows up under "Ports (COM & LPT)" (what you want) or under "Portable Devices"/MTP (a sign that Spanner mode isn't active, or that the driver installed by Express has taken over). Also enable "Show hidden devices" and clear out any "ghost" COM port entries left behind by a driver reinstall — a fairly common issue on these devices under Windows 10/11, which can make a different COM port appear on each connection.
5. In AVP's GPS tab: once you've identified the right COM port, click "Refresh ports" after reconnecting the device, select that port, and leave the speed at the default 4800 baud; if nothing happens after a few seconds, try 9600, then 38400 or 115200 (the manual covers these four values).

No. The ephemerides, star catalog, constellations, basemap, and — in the Pro edition — the 4,170 tide stations are all embedded in the software and computed offline.

They are computed automatically from harmonic constants (source: TICON-4/NOAA, via the Neaps database) and given for indicative purposes. As the software itself notes, they do not replace official tide publications or regulatory means of navigation — verify before making any real navigational decision.

By email, via the Contact page. Since the software is brand new, feedback on bugs, glitches or inconsistencies is especially useful.

A former merchant-marine master mariner (French C1NM certificate), now retired, who put his modest computer skills — and today's artificial intelligence tools — to use in building this software. More on the Contact page.