# `OpticalTube` An `OpticalTube` is the optical tube assembly, or OTA: the lens or mirror that collects the light. It has no driver. Two OpticalTrains can name one tube, such as an imaging train and an off-axis guider. ## spec The tube's optics. | Field | Type | Required | Description | | --- | --- | --- | --- | | `telescope` | string | yes | The name of the `Telescope` that the tube is on. Pattern: `^[a-z0-9]([-a-z0-9.]*[a-z0-9])?$`. | | `aperture` | number | yes | The diameter of the lens or the primary mirror, in millimeters. | | `focalLength` | number | yes | The focal length, in millimeters, with any reducer or barlow that stays on the tube. | ## status What the operator observes. The operator writes it, and a person reads it. | Field | Type | Required | Description | | --- | --- | --- | --- | | `observedGeneration` | integer | no | The `metadata.generation` of the spec that the operator last acted on. | | `conditions` | [\[\]object](#statusconditions) | no | `ParentFound` is `False` when the `Telescope` or its `Observatory` does not exist. | | `display` | [object](#statusdisplay) | no | The spec as a person reads it, with its units, for the printer columns. | | `trains` | []string | no | Each `OpticalTrain` that names this tube. | ### status.conditions[] One condition, in the shape of `metav1.Condition`. | Field | Type | Required | Description | | --- | --- | --- | --- | | `type` | string | yes | The condition's name, such as `Ready`. | | `status` | string | yes | Whether the condition holds: `True`, `False`, or `Unknown`. One of: `True`, `False`, `Unknown`. | | `observedGeneration` | integer | no | The `metadata.generation` of the spec that the condition reflects. | | `reason` | string | yes | One word in CamelCase for the cause. | | `message` | string | yes | The cause, for a person to read. It can be empty. | | `lastTransitionTime` | string | yes | When `status` last changed. A write with the same status keeps this time. | ### status.display The spec as a person reads it, with its units, for the printer columns. | Field | Type | Required | Description | | --- | --- | --- | --- | | `aperture` | string | no | The aperture, such as `80 mm`. | | `focalLength` | string | no | The focal length, such as `480 mm`. |