Motorized Tilt Adapter¶

For most tilt adapters, the correction loop ends with you and a hex key: the Tilt & Aberration Inspector measures the tilt, and the guidance table says which screw to turn by hand. A motorized adapter closes that loop in software. Select one of the ASG Electronic EAT presets in the Tilt Adapter Wizard, connect the adapter over its serial port, and the wizard runs its calibration hands-off, sending the motor moves itself. Once a connected calibration completes, the inspector gains an Automatic Adjustment button that turns a measurement into motor commands, shows them to you for approval, and executes them. A built-in Simulator port drives the Camera Simulator's virtual adapter the same way, so the entire workflow can be tried with no hardware attached.

Motorized device presets¶

The Device list in the wizard includes two motorized presets, ASG Electronic EAT - 90mm and ASG Electronic EAT - ZWO 461. Selecting either one makes a Motorized Device Connection section appear below the preset. For the Manual entry and every screw preset the section stays hidden, and the wizard behaves exactly as described on the Tilt Adapter Wizard page.

The EAT is a 4-screw adapter whose motors move in coupled groups: a corner command drives that corner's motor forward and the opposite corner's motor backward, and a backfocus command drives all four together. The plugin plans corrections in those native moves, so a full tilt-plus-backfocus correction takes at most three commands.

Connecting¶

Plug the adapter in and pick its COM port under Serial port (the ⟳ button re-scans the list). The port is saved per profile.
Click Connect. Opening the port restarts the adapter's controller, so it takes a few seconds to boot before it responds; the status line then reads Connected on COM7 (or whichever port you chose). There is no auto-connect: the plugin only opens the port when you click.
Click Disconnect when you are done. If the connection sits unused for 30 minutes, a banner in the tilt panels counts down for a minute and then disconnects on its own. Stay connected keeps it, and so does moving the adapter or starting a run.

While connected, a Motor positions (steps) grid shows each corner's current position counter, polled from the device. Each cell names its corner and the screw it holds (TR · M1, TL · M2, BL · M4, BR · M3 by default), with the motor number and the wizard screw number underneath. The counters read "unknown" until the first successful position query, and during a calibration run each one also shows Δ, its change since the run started.

Selecting either EAT preset names the screws after its motors everywhere in HocusFocus, so the guidance table and the wizard prompts say "M4" rather than "Screw 3". Rename them under Screw Labels in the wizard settings if you prefer your own names; see Naming your screws.

The counters are absolute and stored in the adapter's EEPROM: they survive power cycles and do not reset between sessions, so they carry whatever position your earlier adjustments left them at. The plugin never zeroes them; if you want the counters re-zeroed, do it in the vendor's app.

Automation keeps every motor inside a travel window of 0 to Max excursion. Travel below 0 is never sent, so the useful working room is whatever sits between your current counters and the cap.

Hands-off calibration¶

With the device connected, the wizard performs its own calibration moves instead of prompting you to turn screws, and the step instructions describe what the wizard is about to send rather than what you must do.

Steps applied per screw defaults to 150 steps for the EAT presets (270 µm at 1.8 µm per step), large enough that each calibration move stands well above measurement noise. The value must fit within the safety limits before a run will start.
The first time you connect in a session, the wizard turns on Measure direction, adding 2 steps to the run, and notifies you. With Measure final re-baseline also at its default (on), a freshly-connected device runs the full 7-step calibration. Leaving Measure direction on is recommended: the adapter's direction is then measured with the same backfocus command that Automatic Adjustment later sends. If you turn it off, backfocus moves keep an "(assumed direction)" warning.
Auto Run All drives every remaining step without further clicks: the wizard sends the step's move, runs the measurement, and advances. With Measure final re-baseline on, the last measurement step already restores and measures every motor, so the run finishes there; with it off, the wizard finishes with an additional, unmeasured restore move that returns every motor to its starting position. To step through manually instead, use Run This Step (the Run Measurement button is relabeled while a motorized device is connected), which sends one step's move and measurement at a time.
Cancelling an automated run (Cancel Run) is safe but not instant: the device has no abort command, so the in-flight move and measurement finish first, and the wizard then sends the inverse of every move applied so far, returning the adapter to its starting position.

Completing a calibration with the device connected also records that the calibration is linked to that device: because the wizard sent every move itself, the correspondence between wizard screws and physical corners is established by measurement rather than assumption. Automatic Adjustment requires that link, and requires the calibration to have passed its own confidence check. The link is cleared by any calibration the wizard did not drive itself: a Manual Calibration Entry, a replayed calibration, a run performed without the device connected, substituting Use Saved AF for a live measurement partway through a connected run, or copying the Camera Simulator's adapter geometry over it.

A hand-entered calibration is the one case you can re-link without repeating the run. With a motorized preset selected, the wizard's saved-calibration panel offers Trust This Calibration for Automation, which links the calibration to the selected preset and marks it reliable, the two things Automatic Adjustment tests for. Confirm the numbering yourself before you use it: with Manual adjustment, move one screw a small amount and check that the corner that moves is the one you expect for that screw's label. Trusting lifts nothing else, so Automatic Adjustment still needs a connected device and a fresh measurement to adjust from. It is not offered for a run that drove the device but failed its confidence check. That case has to be re-measured: confirming which corner moves proves the numbering, and numbering is not what a noisy run got wrong.

Automatic Adjustment¶

While the device is connected, the inspector's Tilt Adapter Guidance section shows the live motor positions and an Automatic Adjustment button beneath the numeric guidance table. Clicking it computes a move plan from the current measurement's fitted sensor model (the same numbers the guidance table displays) and opens a Review motor commands dialog. Nothing moves until you approve the plan there.

The dialog shows:

Apply checkboxes for Tilt correction and Backfocus correction. Toggling either one recomputes the plan, so the listed moves are always exactly what will be sent.
The moves to send, each described by which screws travel and by how many signed steps, with the raw serial command alongside for auditing.
The residual left at each screw after the moves: plans are rounded to whole steps, which leaves at most about one step (1.8 µm) of error per corner.
Warnings when something needs attention: the adapter direction is still assumed rather than measured, the saved step size disagrees with the wizard's last measured value, the measured tilt contains a twist component that no rigid adapter can remove, a backfocus bias had to be added to keep the motors at or above 0, or a move would violate a travel limit (which disables sending).
The move count and an estimated duration. Each move takes roughly five to ten seconds.

Cancel sends nothing. The confirm button, labeled Send 2 moves (or however many are planned), executes the moves in order and then offers to re-run the Aberration Inspector to confirm the improvement. Every move is physical and is stored in the adapter's EEPROM, so review the list before sending; there is no automatic undo.

One adjustment per measurement

After a plan executes, Automatic Adjustment stays disabled until a new Detailed Analysis completes, so the same measurement can never be applied twice and every adjustment is confirmed by a fresh measurement before the next one. A failure partway through a plan brings a revert offer.

If the confirming run says tilt got worse¶

The plugin shows a red "Tilt got worse after the last adjustment" panel at the top of the Tilt Adapter Guidance section, quoting the tilt magnitude before and after and the number of moves that were sent. It stays there until you act, so you can look at the numbers before deciding. While it is up, Automatic Adjustment is disabled, so a second plan cannot be computed from a measurement you have not accepted.

Revert the N moves sends the inverse of each move, in reverse order, and then requires a fresh analysis before adjusting again.
Dismiss accepts the worse state and re-enables Automatic Adjustment, so you can correct forward from it.

Tilt getting worse usually means a stale calibration, a camera or adapter rotated since it was calibrated, or an incorrect screw-direction setting, all worth investigating before adjusting again. If the device disconnects while the panel is up, the panel stays and explains that reverting needs the device back.

Returning to an earlier measurement¶

Every Aberration Inspector run in the current session records what the adapter looked like at the time, and the Sensor Model Tilt Measurement History grid gains two columns to make a row identifiable: Time, and Pos (✓ when motor positions were recorded, so a one-click return is possible).

To find the run you want back, select candidates and read the Return panel: it states whether returning there would actually move anything, and by how much. That is a better answer than a "was this one adjusted?" marker could give, because it compares the measurements rather than tracking what the plugin happened to send, so it sees adjustments made by any means.

Selecting a row is view-only (it shows that run's numbers and nothing more) and fills in a Return to run #N panel below the grid. That panel previews exactly what would be sent before you click anything:

With recorded motor positions (a motorized adapter that was connected at the time) the return is exact and uses no calibration at all: it simply drives each motor back to the counter value recorded then. Click Drive Adapter to Run #N Positions and approve the usual plan dialog.
If the counters are unchanged but the measured tilt is not, the adapter was moved by something other than these motors: screws turned by hand, a re-seat, the vendor app, or the camera simulator's own tilt controls. Driving the motors back would do nothing, so the panel says so and computes the move from the two fitted models instead. On a motorized adapter you can still drive that.
Without them (a manual-screw adapter, or a run measured with nothing connected) the panel computes the motion from the difference between that run's fitted model and the current one, and shows it as per-screw turns. This needs no record of what you actually did between the runs, but it is only as good as the two fits, and it assumes nothing but the tilt adjustment changed. The panel says so.

Selecting an old run changes the guidance table

While a past run is selected, the guidance above shows how to flatten the sensor from that run's state, which is not how to get back to it. A note appears above the table saying so.

History is per session

Runs are remembered for as long as NINA is running. After a restart the history is empty, so there is nothing to return to, even though the adapter itself still knows where its motors are.

Manual adjustment¶

Automatic Adjustment corrects a tilt the plugin has just measured. When you want to move the adapter yourself — to lift motors away from 0, to dial in backfocus, to apply a correction you worked out elsewhere, or to finish an adjustment that stopped partway — open Manual adjustment in the Motorized Device Connection section, directly under the motor positions. It is collapsed by default, and its header line says what it last did.

Unlike Automatic Adjustment, it needs no measurement and no calibration: it drives the hardware directly, so it works as soon as the device is connected.

Every move here is physical and is stored in the adapter's EEPROM. There is no automatic undo.

Single move¶

Pick what to move on the 3×3 pad, which is laid out the way the sensor is imaged:


TL	Top	TR
Left	All	Right
BL	Bottom	BR

The four corners tilt along a diagonal, the four edges tilt one side against the other, and All moves every motor together — a backfocus change, not a tilt. Each is a single command to the device.

Set Direction (+ is the wizard's positive step direction; − is its opposite) and Amount in steps, and the preview below shows exactly what the click will do: which motors move and by how much, where all four will end up, how much of the travel window that leaves, and the change in microns. Because the adapter's corners are mechanically coupled, choosing TR also moves BL — the preview always shows both, so the coupling is visible before you send anything.

Send issues the move. Nothing else changes, so repeating the same nudge is one more click. An amount larger than Max steps per command is sent as several commands in the same direction, and the button says how many.

A move that would carry a motor outside the travel window is refused before anything is sent, and the panel names the motor and suggests the fix — usually an All + move to lift everything first. Positions that end near either end of the window are tagged near 0 or near max; those are advisories, not refusals.

Target positions¶

Switch Mode to Target positions to say where each motor should end up rather than how far to move it. The four boxes are filled in from the current positions; edit the ones you want to change and the panel shows the difference per corner and how many moves it will take.

Review moves… decomposes the difference and opens the same Review motor commands dialog that Automatic Adjustment uses, with the same move list, residuals and warnings. Nothing is sent until you approve it there.

Four numbers, three degrees of freedom

A tilt adapter can tilt the sensor plane and change its spacing, but it cannot twist it — no rigid plane can. Most sets of four hand-typed positions ask for a little twist, and that part simply cannot happen. When the request contains a whole step of twist or more, the panel says so before you open the dialog and each corner shows the position it will actually reach.

If a plan stops partway — a failed command, or Stop after this move — the moves already sent stay applied. Because the targets are absolute, pressing Review moves… again once the positions have re-synced re-plans from wherever the motors actually are, which finishes the remainder.

Safety limits¶

Three persisted settings in the Motorized Device Connection section, under Safety Limits, bound what automation may send:

Setting	Default	What it does
Max steps per command	200	Cap on the magnitude of a single commanded move. Larger planned moves are split or refused.
Max excursion (steps)	2000	Upper bound of the travel window. Every motor is kept between 0 and this value; a move that would carry one outside it is refused before anything is sent.
Settle time (s)	3	Seconds to wait after each commanded move before polling positions or sending the next command.

The excursion limit is compared against the adapter's absolute, EEPROM-persisted counters, not against how far the current session has moved. It is the upper bound of a travel window whose lower bound is fixed at 0: with the default of 2000, every motor is kept between 0 and 2000. Because the counters carry over between sessions, the cap has to exceed wherever your motors currently sit plus the travel you intend to use — a limit set tighter than a motor's current position refuses the very first move, however small that move is. A refused move names the motor and the position it would have reached, and nothing is sent.

Why corrections near zero add a backfocus move¶

A tilt correction is differential: it drives one corner up and the opposite corner down by the same amount. With the motors at or near 0 there is nothing below to give, so the correction cannot be applied as-is.

Rather than refuse it, the plugin lifts the whole adapter first: it prepends a backfocus bias, a move that raises all four motors by the smallest amount that keeps the correction inside the window. The approval dialog shows the bias as its own move and warns that it is present.

The bias is not free. Moving all four screws together is a backfocus change, so it shifts your backfocus by the bias amount, and that shift is included in the residuals the dialog reports. To avoid it, give the motors room to work before adjusting, so corrections have travel underneath them: send an All + move from Manual adjustment, or raise the motors away from zero in the vendor's app.

The Simulator port¶

When a motorized preset is selected, the Serial port list always offers Simulator as its first entry. Connecting to it drives the Camera Simulator's virtual tilt adapter instead of real hardware. Everything behaves as it does with the real device, and the injected tilt converges toward flat as corrections are applied, so you can walk through the whole motorized workflow at your desk before connecting a real adapter.

Connecting to the Simulator port checks three preconditions:

The Hocus Focus Simulator must be the connected camera. Otherwise the connect is refused with an error, since the simulated adapter only changes the simulator's images.
The simulator's tilt-adapter geometry (screw count, adjustment type, step size, screw radius) must match the selected EAT preset, or the calibration loop cannot converge. If they differ, a dialog offers to change the simulator's configuration to match; declining aborts the connect.
Enable Aberrations on the Camera Sim options tab is switched on automatically (with a notification) if it was off, because the loop measures nothing on aberration-free frames.

Troubleshooting¶

Connect fails or the port is missing. Click ⟳ to re-scan after plugging the device in, and make sure no other program (the vendor's app, a serial monitor) is holding the port. The adapter takes a few seconds to boot after the port opens, so a slow first response is normal.

Automatic Adjustment is not visible. The button only appears while a device is connected. Connect it from the wizard's Motorized Device Connection section; the inspector uses the same connection.

Automatic Adjustment is disabled, with an italic note below the button. The note names one of three causes.

"This calibration was entered or edited by hand..." The saved calibration came from Manual Calibration Entry, or from copying the Camera Simulator's adapter geometry over it, so nothing has confirmed that its screw 1 is the corner the device's motor 1 drives. Run a calibration with the device connected (Auto Run All is the easiest path), or use Trust This Calibration for Automation in the wizard after checking the numbering as described above.
"This calibration is not linked to the connected device." The calibration was measured some other way: replayed from disk, run with nothing connected, or measured against a different Device preset than the one now selected. Re-select the preset it was measured on, or re-run the calibration with the device connected. Unattended automation applying a rotated correction would make tilt worse, which is why the link is required.
"This calibration is low-confidence (it did not pass quality validation)." The run did drive the device, but its screw moves did not stand clear of the measurement noise. Re-run it on a star-rich field with a finer focus step. There is no Trust button for this case; only a better measurement clears it.

Automatic Adjustment is disabled right after an adjustment. That is the one-adjustment-per-measurement rule. Run a new Detailed Analysis; the button re-enables when it completes. It is also disabled while a "Tilt got worse" panel is showing (revert or dismiss it first) and while an analysis is running.

The device disconnected on its own. After 30 minutes with no activity the plugin shows an amber banner in the tilt panels counting down, and disconnects when it reaches zero. Clicking Stay connected cancels it and restarts the 30 minutes, as does simply moving the adapter or starting a run, which count as activity. If it did disconnect, the connection line says so with the time it happened; just connect again.

A move was refused by a limit. The error says which limit. For Max steps per command, either reduce the amount being sent (for calibration, Steps applied per screw) or raise the limit. For Max excursion (steps), remember the check is against the absolute counters: a motor already sitting near the cap has no headroom left, so either raise the cap or re-zero the counters in the vendor's app.

A move was refused for going below 0. Travel below zero is never sent. During a calibration run (which sends its moves directly rather than through the planner) this means the motors are sitting too close to zero for a differential move of that size — raise them first, in the vendor's app or with a positive backfocus move, then re-run. If a motor is already at a negative counter from earlier work outside the plugin, no move will be accepted until you re-zero it in the vendor's app.

The Simulator port refuses to connect. Connect the Hocus Focus Simulator camera first, and answer Yes when asked to change the simulator's tilt configuration to match the preset (or align the two yourself on the Camera Sim tab).