SDSO Skycam

Capture an image as a FITS and serves it via a web API.

The SDSO skycam uses the following hardware:

• ZWO ASI224MC
• 1.55mm f/1.5 CS Mount Lens
• Raspberry Pi Zero 2 W
• Waveshare PoE / USB HAT

The pi is powered via PoE and the camera is connected via USB. The ZWO SDK is used to capture an image and serve it via a FastAPI web app. An external service starts an image exposure, polls for status, and downloads the image. Prometheus metrics are also exposed for integration into the observatory monitoring system.

Run

A camera is required to run the app.

For development:

pip install -r requirements.txt
uvicorn app.main:app --reload

As a container:

You must pass through the USB camera. Use lsusb to determine the bus address.

alex@skycam:~ $ lsusb
Bus 001 Device 004: ID 0bda:8152 Realtek Semiconductor Corp. RTL8152 Fast Ethernet Adapter
Bus 001 Device 003: ID 03c3:224a ZWO ASI224MC
Bus 001 Device 002: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The camera is at on Bus 001 as Device 003 so the path is /dev/bus/usb/001/003.

docker run -d -p 80:80 --device=/dev/bus/usb/001/003 --pull=always --restart unless-stopped --name=skycam sdso/skycam:latest

Once up and running, you can start an exposure, poll for its status, and download the completed image.

Start an Exposure

POST /camera/expose
Content-Type: application/json
{
  "exposure": 3.0,
  "gain": 50,
  "offset": 10
}

Get Status

GET /camera/status
Content-Type: application/json
{
  "status": "exposing",
}

Download Image

GET /camera/image
Content-Type: application/octet-stream
Content-Length: 1234
<binary data>

Build

The container is cross-compiled for arm64v8. You may need to apt install qemu-user-static to build the container on x64.

DOCKER_BUILDKIT=1 docker buildx build --platform linux/arm64v8 -t sdso/skycam:latest .

Deploy

docker run -d -p 80:80 --device=/dev/bus/usb/001/003 --pull=always --restart unless-stopped --name=skycam <registry_url>/sdso/skycam:latest