Digital functions and coordinated operations

Scope: fine guiding, nodding/dithering, image display and quicklook, signal monitoring, and astrometry/alignment. These functions use the capabilities described in ZFront/ZCal, ZImager, and ZSpec.

Measurements and observing flows are developed in the calibration and acquisition procedures.

Fine guiding, nodding, and dithering

Function	Inputs	Results and status	Details still needed
Measure slit-relative position	Slit-view image, target selection, slit calibration	Position, uncertainty, image time	Measurement method and usable signal range
Start/stop fine guiding	Arm, target/reference, requested position	Applied correction, tracking error, active/held state	Correction limits and update rate
Run a nod/dither pattern	Arm, positions, exposure/dwell settings	Current position and pattern progress	Pattern options and guiding during moves
Stop a pattern	Pattern	Final position and exposure state	Finish-current-exposure versus immediate interruption

VIS and NIR need independent guiding and offset patterns, including non-sidereal operation. Internal steering and telescope offsets will need an agreed division with the facility guider.

Image display and quicklook

Function	Inputs	Status and results	Details still needed
View images	Channel, raw/corrected view	Images, timestamps, acquisition settings	Stream interface and calibration selection

Signal monitor

Measurement	Inputs	Output
Source and slit placement	Slit-view or acquisition images, target and slit definition	Detection, position, acquisition quality
Signal quality	Science images, detector settings, applicable calibrations	Signal/noise estimate, saturation and technical warnings
Observing feedback	Measurements from the active exposure or series	Recommendation to continue, adjust, or reacquire, with the relevant measurements

The operator retains the choice of observing intent. Missing images or stale measurements need a clear indication in the displayed result.

Astrometry and alignment solver

Function	Inputs	Results and status	Details still needed
Solve a field	Image and catalog/reference	Coordinate solution, residuals, uncertainty	Solver and reference inputs
Measure relative alignment	Imager/slit-view images, optical configuration, calibration measurements	Relative positions and transforms	Configuration dependence
Use a calibration solution	Selected solution	Active solution and applicable configuration	Selection and storage interface

Point-source, displaced-source, rotator/ADC, and on-sky measurements are described in the calibration procedures. A service event need not discard a still-valid alignment solution.

Coordinated operations

Operation	Device capabilities used
Configure and acquire a target	Beam routing, slit selection, focus, rotation, ADC, images and steering
Take independent channel exposures	Per-channel acquisition with shared shutter/path constraints
Run a nod/dither pattern	Steering, guiding, and acquisition
Apply a named calibration configuration	Calibration insertion, point/extended source, source and brightness

Team notes: Allocation among ICS, quicklook/DRP, and facility services remains open. The tables can grow with concrete command examples as those interfaces are agreed.