The guider

A Guider runs PHD2 for its Telescope, with the camera of the OpticalTrain it names. StartGuider starts PHD2, connects it to the camera and the mount, and leaves it idle. The operator never loops, calibrates, or guides: tracking stays off after activation until the holder aligns the mount, so the holder drives PHD2 from then on. KStars or astrophotography-operator connects to PHD2’s event server at the Guider’s status.endpoint, such as east-guider.observatory.svc:4400.

The guider’s pod runs two containers. PHD2 runs from ghcr.io/liken-sh/indi-phd2, which the indi build makes on the indi image, so PHD2 links the libindi of the server it talks to. PHD2 has no headless mode, so it draws on a headless weston in a native sidecar, through a Wayland socket that the two containers share. The sidecar is the weston image that display-operator builds on, at the tag that weston/package.toml pins, so a node that runs display-operator pulls no new image for it, and one bump of weston moves both. The pod has no device claim, and it runs on the node of the telescope’s server, because PHD2 reads a guide frame from the server about once a second.

PHD2 writes its config while it runs, so the operator writes the whole profile into the ConfigMap <guider>-guider, and the image copies it into $HOME before each start. The profile names the INDI server, the guide camera and the mount as the server names them, the guide tube’s focal length, and where the pulses go: spec.pulses: Mount sends them to the mount’s driver, and Camera to the guide camera’s ST-4 port. A change to the profile replaces the pod.

StopGuider deletes the pod before Disconnect, so PHD2 never sees its devices drop. On a compositor with no seat, a modal dialog ends PHD2, and the kubelet starts it again: plan 09 lists the dialogs that PHD2 can open.

A Guider’s status holds what PHD2 reports while the operator’s connection to its event server is open:

• state: PHD2’s state, Stopped, Selected, Looping, Calibrating, Guiding, LostLock, or Paused.
• calibrated, and pixelScale in arc-seconds per pixel.
• rms: the RMS of the star’s distance from the lock position in right ascension, declination, and total, in arc-seconds, over the last 100 guide steps that the operator received since guiding started. rms.since is the time of the first of those steps. PHD2 sends a new connection no earlier steps, so the window also starts again when the operator restarts.
• star: the guide star’s SNR and its HFD in pixels, and lastStepTime, from the last guide step.
• alert: the last alert PHD2 showed, or the last calibration that failed.

The Ready condition is True while PHD2 runs and reports its camera and mount connected. The status writer writes at most once a second, so a guide step a second costs one write a second.

kubectl get guider -n observatory
kubectl port-forward -n observatory svc/east-guider 4400