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Target Scheduler

Concepts

Conceptually, the plugin is divided into three separate areas:

  • Project, Target, and Exposure Plan Management
  • Runtime execution via the Advanced Sequencer using the Target Scheduler Container instruction
  • Post-acquisition activities

Project and Target Management

The plugin organizes your acquisition data as follows. Note that all of these entities are unique to a given NINA profile since they often depend on the characteristics of the associated equipment.

Projects

Projects serve to group a set of Targets and provide common preferences. Although many projects will have only a single target, it may be useful to group related targets under a single project - for example the separate panels of a mosaic.

Targets

A target represents a single DSO object with RA/Dec coordinates, frame rotation, and ROI. Target coordinates can be manually entered or imported from the NINA catalog, the NINA Framing Assistant, a saved sequence target, or an attached planetarium program (e.g. Cartes du Ciel, Stellarium, etc). You can also import mosaic panels defined in the Framing Assistant and also load targets from CSV files (including Telescopius).

Exposure Plans

Each target has one or more associated Exposure Plans that describe the actual exposures to be taken. An individual exposure plan sets the exposure length (if you need to override the template default) and the number of exposures desired, as well as referencing an Exposure Template (see below). Exposure plans also record the number of images for this plan that are deemed acceptable (which can be edited) plus the total number acquired (which can’t be changed). An exposure plan will stay active until the number of accepted images is greater than or equal to the number desired (or the Exposure Throttle has stopped it).

Exposure Templates

Exposure Templates provide the ability to set several exposure-related properties that are likely to be common for the associated filter and the rig described by the applicable profile. Configurable properties include a default exposure time, gain, offset, binning, and camera readout mode. You can also set the level of twilight and the moon avoidance parameters appropriate for the filter.

Exposure Templates let you decouple most of the properties for an exposure from the Exposure Plan so that they’re easy to reuse. You can also define multiple templates for the same physical filter.

Note that you must set up an Exposure Template before you can define any Exposure Plans that use it.

See Project/Target Management for details.

Previewing Schedules

Once you have entered a set of projects, targets, and exposure plans, you can preview what the scheduler will do on any given night. Be aware that the previews are merely representative of what the scheduler will do. See Scheduler Preview for notes and caveats.

Runtime Execution in the Advanced Sequencer

The plugin provides a single primary instruction for the NINA Advanced Sequencer: Target Scheduler Container. The instruction is placed into a Sequential Instruction set. You can also add other NINA instructions to custom event containers and have them run when specific events occur, like starting a new target.

A perfectly valid sequence could consist of nothing more than start up instructions (connect equipment, cool camera), the sequential instruction set containing Target Scheduler Container and required triggers, and end instructions (park, warm camera, disconnect).

When the instruction executes, it does the following in a loop:

  • Query the Planning Engine for the best target to image at the present time. If no target is available now but will be later, it will automatically wait for that time before calling the Planning Engine again.
  • If the planner selected a target, it will return the instructions to take a single exposure. If the target is different from the previous target, the instructions will include a slew to the target (and rotate if needed) and then center (plate solve).
  • The container will then begin executing instructions: slew/center (if needed), switch filter, (optionally) dither if needed, and exposing.
  • When the instructions complete, the container loops back and calls the planner again. To avoid excessive slew/centers, the planner has provisions to ‘stick’ with a target for at least a minimum period of time.
  • If the Planning Engine returns null, the instruction completes.

The plugin provides additional instructions for the advanced sequencer:

  • Custom loop conditions can be added to your sequence to control continuation based on the planner status.
  • Since Target Scheduler is controlling acquisition, you can also configure it to take flats automatically.
  • If you have multiple OTAs/cameras on the same mount, you can use synchronization to have them image at the same time.

See the Advanced Sequencer for details.

Planning Engine

The Planning Engine executes a series of steps to pick the best target to image at the moment and then schedule the applicable exposures for that target. See Planning Engine for details.

Post-acquisition Activities

Image Grading

In order to increase the level of automation, the plugin includes rudimentary image grading. The grader will compare metrics (e.g. HFR and star count) for the current image to a set of immediately preceding images to detect significant deviations. If the image fails the test, the accepted count on the associated Exposure Plan is not incremented and the scheduler will continue to schedule exposures. The grader can also grade based on the total RMS guiding error over the exposure duration, as well as FWHM and eccentricity (if Hocus Focus is used).

Grading can also be delayed so that some percentage of the total desired for an exposure plan must be acquired before grading is triggered. The calculations can then be based on a larger sample of exposures, mitigating problems caused by early images being unrepresentative of a larger population.

Automatic image grading is inherently problematic and this plugin is not the place to make the final determination on whether an image is acceptable or not. Towards that end, the plugin will never delete any of your images. You are also free to disable Image Grading and manage the accepted count on your Exposure Plans manually - for example after reviewing the images yourself or using more sophisticated (external) analysis methods.

See Image Grading for details.

Flats

Since the plugin is controlling your target acquisition, it knows all the details required to take flats for those targets and exposures. Assuming you have run the NINA Flat Wizard to calculate the flat exposure times for each filter, you can add the Target Scheduler Flats instruction to the end of your sequence to take any flats that are needed.

If you use a rotator, the flats instruction will move it to the same mechanical angle that was used for the corresponding target. If your rotator has problems trying to duplicate a previous position, you can use the Target Scheduler Immediate Flats instruction to take flats immediately after target exposures were taken, before the rotator moves to a new position.

Note that this will only work with a flat panel - sky flats are not supported.

See Flat Frames for details.

Reporting

In the Reporting section, you can view an acquisition summary of your targets, including total exposure times by filter and grading status. You can also see details on each exposure, including a thumbnail image. Target reports can be viewed in the Reporting section of the plugin home page in NINA Plugins.

See Reporting for details.

Acquired Images

The plugin will save metadata to the database for all images acquired via the plugin. The records can be viewed in the Acquired Images section of the plugin home page in NINA Plugins.

See Acquired Images for details.

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