polyoculus-node

Everything that runs on a PolyOculus telescope node: one of the lab's original 2019 Jetson Nanos (p3450, 4 GB), each driving one telescope's mount, guide camera and fast steering mirror. Covers the OS (mainline Linux 7.1 + Arch Linux ARM, replacing NVIDIA's end-of-life Ubuntu 18.04), configuration of the whole fleet, and the lab's node software.

os/          make an SD card into a node: kernel, flashing, first boot, self-naming
ansible/     everything on a Nano after that: packages, time, hardware, INDI, node software
mount/       iOptron CEM70 control over INDI (was pyMountOperator)
camera/      DMK 33UX273 guide camera + piezo fast steering mirror (was dmk-camera)
guide/       autoguiding: camera centroid -> mount guide pulses (+ an INDI-simulator test)
docs/        how it all works and how to run it

mount/ and camera/ were separate repos; they were imported with their full history.

Documentation

docs/architecture.md	how a node works: boot, services, names, time, access
docs/new-node.md	flashing a card for a new Nano or replacing a dead one
docs/operations.md	running the fleet: deploying changes, updates, access, names, data
docs/observing.md	an observing night: pointing, focus, guiding, the mirror
docs/troubleshooting.md	boot problems, unreachable Nanos, hardware, cards
docs/kernel.md	the custom kernel: why, building, publishing, updating
os/README.md, ansible/README.md	reference: every script, role and setting
mount/, camera/, guide/	the node software

The rules

Cards are interchangeable. The Nanos are identical boards, and a Nano names itself at every boot from the hardware it's attached to: ansible/nodes.txt maps guide camera serials (the camera stays with its telescope) and board MACs to node names. Put any card in the Nano on telescope 3 and it becomes that node. There is no other per-node configuration anywhere.

Nothing lives only on the SD card. SD cards die. Every Nano is rebuildable from this repo in ~20 minutes, so observation data and calibration files get copied off after every session. Keep a pre-flashed spare card at the observatory.

No passwords. Nodes outlive the people who set them up, so there is nothing to remember or hand over: alarm logs in at the console with no password, root is locked, sudo asks for nothing, and SSH accepts the keys in ansible/files/authorized_keys/.

Quick start

A new card (x86_64 Linux laptop with uv, rsync and gh; details in docs/new-node.md):

cd os
./build-kernel.sh                 # downloads the published kernel
sudo ./flash-card.sh /dev/sdX     # check the device with lsblk first!

Put it in a Nano with Ethernet (internet) and power it on; it sets itself up and reboots (~20 min). Then, from the laptop on the same network:

ssh alarm@nano-03.local                                    # no password: your key
cd ansible && uvx --from ansible ansible-playbook site.yml # push any repo change to every Nano