Raspberry Pi

citrasense-pi is a turnkey SD card image that transforms a Raspberry Pi into a dedicated telescope node. Flash it, power on, connect to WiFi from your phone, and the dashboard is live — no SSH, no terminal, no manual setup.

What’s on the image

Component	Details
OS	Raspberry Pi OS Lite ARM64 (Debian Trixie)
CitraSense	Auto-starts on boot, dashboard on port 80
INDI	Pre-installed drivers — CitraSense starts them as needed
GPS timing	Automatic detection; UART + PPS for Stratum 1 accuracy, USB GPS for position
WiFi	Captive portal for network setup, automatic hotspot fallback
SSH	Enabled on port 22
User	citra / citra (sudo enabled)

Supported models: Raspberry Pi 4 (2 GB+) and Raspberry Pi 5.

First boot

Your device gets a mission name

On first boot, the Pi picks a random name from famous space missions:

voyager, hubble, galileo, juno, kepler, pioneer, viking, luna, apollo, gemini, mercury, atlas, titan, orion, phoenix, spirit, curiosity

This name is permanent. It becomes the WiFi hotspot SSID, the network hostname, and how you find the device on your network. If yours draws voyager, everything is citrasense-voyager from here on out.

Connect to WiFi

If the Pi has no Ethernet connection, it creates a hotspot:

1. On your phone or laptop, look for citrasense-{name} in the WiFi list
2. Connect with password: citra
3. A captive portal appears — pick your WiFi network and enter its password
4. The Pi joins your network and the hotspot disappears

If your WiFi goes away — field use, power outage, router reboot — the Pi automatically brings the hotspot back so you can always reconnect.

Open the dashboard

Once you’re on the same network:

http://citrasense-{name}.local

For example, http://citrasense-voyager.local. The dashboard runs on port 80, so no port number is needed. From here the experience is identical to a desktop CitraSense install — connect to the Citra Space API, select your hardware, and you’re imaging.

SSH access

ssh citra@citrasense-{name}.local

Default password is citra. The login banner shows your device name and dashboard URL as a reminder.

GPS (optional)

The image comes pre-configured for GPS. Plug in a receiver and it works automatically.

GPS type	Position	Timing
USB GPS	Yes	Internet NTP only (no improvement)
UART GPS (no PPS)	Yes	Coarse — NMEA timestamps via gpsd
UART GPS + PPS on GPIO 18	Yes	Stratum 1, microsecond accuracy via chrony

For best results in the field (no internet), use a UART GPS with PPS. The image configures gpsd, chrony, and the PPS overlay automatically — just wire PPS to GPIO 18.

Check GPS: cgps -s

Check time: chronyc sources -v

Image versioning

Release filenames use dual versioning so you know exactly what’s on the card:

citrasense-pi-v0.4-cs1.3.0.img.xz
              ────  ───────
              │     └─ CitraSense version (telescope control software)
              └─ Pi image version (OS config, drivers, WiFi, GPS setup)

The build always installs the latest CitraSense release available at build time.

Troubleshooting

Can’t reach citrasense-{name}.local:

• Make sure your device supports mDNS (most do; older Windows may need Bonjour)
• Try the Pi’s IP address directly — check your router’s client list
• If you’ve forgotten the name, look at your WiFi list for the hotspot SSID

WiFi hotspot not appearing:

• Wait 1–2 minutes after power-on
• Make sure WiFi isn’t disabled on the Pi (shouldn’t be, but verify with Ethernet + SSH if needed)
• Try power cycling

Forgot the device name:

• The hotspot SSID shows the name — check your WiFi list
• Or connect via Ethernet and run hostname