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Scripting and data analysis

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Jimmy Nordström edited this page Nov 1, 2026 · 4 revisions

The Scripts workspace lets you automate Sidralune and analyse data with C# scripts that have access to the whole program: catalogues, ephemerides, image processing, plate solving, photometry, devices and the user interface. It also has a Data analysis tab for quick plots and fits of tabular data without writing code.

Contents

C# scripts

Writing and running a script

The editor on the left holds the body of the script: the statements to run. Pick a starting point from the examples list on the toolbar, edit it, and press F5 or click Run (F5).

The script is compiled in memory with the C# compiler built into the .NET Framework, so no extra software is needed. Compilation takes a fraction of a second. If there are errors, they are listed in Output with line and column numbers, and the first error's line is highlighted in the editor.

While the script runs, the button changes to Stop; click it to cancel. Scripts run in the background, so the window stays responsive.

The right side has three tabs for results:

Tab Filled by
Output Print(...), compiler messages, run time, and any exception with its stack trace
Plot Plot(...), PlotTitle(...)
Table Table(...)

When a script finishes with only a few lines of output, the Table or Plot tab is brought forward automatically if the script filled it.

The script API

These members can be used directly in a script:

Member Description
Print(object), Print(format, args…) Write a line to Output, for example Print("{0} stars", n)
Progress(fraction, status) Show progress (0–1) in the status bar
CheckCancel(), Token Stop promptly when the user clicks Stop: call CheckCancel() in long loops, or pass Token to methods that accept a cancellation token
Sleep(seconds) Wait, cancellably
Site The active observing site (Observer): latitude, longitude, elevation, time zone, SQM…
Now The program's current time (AstroTime), live or simulated
Selection The selected object (SelectedObject), or null
Sky A SkyContext for the site and current time: Sky.BodyPlace(Body.Mars), Sky.IcrsToHorizontal(ra, dec)…
Catalogs The catalogue manager: Catalogs.Find("M 31"), Catalogs.Search("Ring", 10), Catalogs.DeepSkyList, Catalogs.ConstellationAt(ra, dec)
Devices The device manager: Devices.Telescope, Devices.Camera, Devices.Focuser, Devices.FilterWheel, Devices.Dome, Devices.Guider…
ClearPlot() Clear the plot
PlotTitle(title, xLabel, yLabel, invertY) Set the plot's title and axis labels; invertY for magnitudes
Plot(name, xs, ys, scatter) Add a series from two lists of numbers, as a line or points
Plot(name, f, x0, x1, n) Plot a function f(x) from x0 to x1
Table(columns, rows) Show a table: a list of column names and a list of rows (each a list of values)
LoadImage(path) Load any supported image as an AstroImage
SaveFits(path, image) Save an image as 32-bit FITS
Files(folder, pattern) Sorted list of files in a folder, for example Files(@"D:\Lights", "*.fits")
Show(image, name) Open an image in the Process workspace

API help on the toolbar lists all of these with their exact signatures, and the namespaces available.

Namespaces

The script is compiled with these namespaces already imported, so their classes can be used without prefixes:

Area Namespaces Useful classes
.NET System, System.Collections.Generic, System.Linq, System.IO, System.Text, System.Drawing, System.Threading List<T>, Math, File, LINQ
Application Sidralune, Sidralune.UI, Sidralune.Views AppState, MainForm, Theme, the workspace views
Core Sidralune.Core, .Mathematics, .Time, .Coordinates, .Ephemeris, .Catalogs, .MinorBodies, .Satellites, .Util AstroMath, Stats, LevenbergMarquardt, AstroTime, Transforms, Events, PlanetPhysics, MinorBodyStore, Sgp4, Csv
Imaging Sidralune.Imaging, .IO, .Analysis, .Processing, .Stacking, .Registration, .Planetary AstroImage, ImageFile, FitsIO, StarDetector, StretchOps, Deconvolution, StackingEngine, StarMatcher, LuckyStacker, Preprocessor
Science Sidralune.Science.Astrometry, .Photometry, .Spectroscopy, .SolarSystem, .Radio, .Databases PlateSolver, Wcs, AperturePhotometry, PeriodSearch, TransitModel, SpectroTools, GalileanMoons, PlanetMoons, OccultationPredictor, RadioMath, OnlineServices
Devices Sidralune.Devices, .Automation DeviceManager, CaptureService, Autofocus, Centering, PolarAlignment, Sequencer

To change the user interface from a script, run the code on the UI thread: MainForm.Instance.Invoke((Action)(() => { … })).

Helper methods

Everything above a line containing //@members is the body of the script; everything below it becomes extra members of the script class, so you can define helper methods and fields:

for (int n = 1; n <= 10; n++) Print("{0}! = {1}", n, Factorial(n));
//@members
static long Factorial(int n) { return n <= 1 ? 1 : n * Factorial(n - 1); }

Language level

Scripts are compiled by the C# compiler that ships with the .NET Framework, which supports C# 5. That means no string interpolation ($"..."), no ?. operator, no expression-bodied members and no nameof. Use string.Format (or Print with a format) and ordinary null checks instead.

Examples

The examples list contains:

Example Shows
Hello sky: planets now Positions, magnitudes and sizes of the planets in a table
Altitude curve of the selection tonight The selected object's and the Sun's altitude over 24 hours as a plot
Batch: FWHM and star count of a folder Measuring every FITS file in a folder: star count, FWHM and eccentricity in a table and a plot, to spot frames with bad focus or tracking
Simulated camera: capture and stretch Taking an exposure with the connected camera, stretching it and opening it in Process
Lomb-Scargle of a synthetic variable Generating a time series and finding its period
Helper methods (//@members) Defining helper methods

A few more ideas:

// When does each Messier object transit tonight?
var rows = new List<IList<object>>();
foreach (var d in Catalogs.DeepSkyList.Where(o => o.Messier != null))
{
    var rs = Events.FixedRiseSet(d.Ra, d.Dec, Site, Now);
    rows.Add(new object[] { d.Messier, d.Name, rs.Transit.HasValue ? Site.ToLocal(rs.Transit.Value.ToDateTimeUtc()).ToString("HH:mm") : "-" });
}
Table(new[] { "Object", "Name", "Transit" }, rows);
// Plate solve every FITS file in a folder and print the centres
foreach (var f in Files(@"D:\Astro\2026-10-18\M 31\LIGHT", "*.fits"))
{
    CheckCancel();
    var img = LoadImage(f);
    var r = PlateSolver.Solve(img, new SolveOptions { Catalog = new LocalCatalogProvider() }, null, Token);
    Print("{0}: {1}", Path.GetFileName(f), r.Success ? r.Wcs.ToString() : r.Message);
}
// Slew the telescope to the selected object (with a connected mount)
var o = Selection;
var app = Sky.IcrsToApparent(o.RaDeg * AstroMath.Deg2Rad, o.DecDeg * AstroMath.Deg2Rad);
Devices.Telescope.SlewToCoordinatesAsync(app.RaHours, app.DecDeg);
Print("Slewing to {0}", o.Name);

Saving scripts

Save… (or Ctrl+S, which saves straight away once the script has a name) stores the script as a .cs file; Open… loads one. The default folder is %LOCALAPPDATA%\Sidralune\Data\Scripts.

Running scripts from the command line

Sidralune.exe --screenshot out.png --script myscript.cs starts Sidralune, runs the script in the Scripts workspace and saves a screenshot when the wait time is over. See Command-line options.

Data analysis

The Data analysis tab plots and fits tabular data without code.

  1. Click Open CSV / table… or Paste from clipboard (for example cells copied from a spreadsheet). Comma, tab, semicolon and space separators are detected automatically, and a header row is used for column names if present.
  2. Choose the X, Y and optional Y error columns.
  3. Choose a Fit: None, Polynomial (of Degree 1–10), Linear (weighted by the errors), Power law y = a·x^b, or Exponential y = a·e^(bx).
  4. Optionally tick Invert Y (for magnitudes), log₁₀ X or log₁₀ Y.
  5. Click Plot.

The results panel shows the number of points, the mean, standard deviation, median and range of Y, the Pearson correlation coefficient, the fitted equation and the RMS of the residuals. The table of data is shown under the plot.

Right-click the plot to copy it, save it as PNG or export the data as CSV.

Other automation

  • The Sequencer automates imaging nights without code; its Run script instruction can start external programs.
  • The command palette runs any command by name.
  • Sequences are JSON files that scripts can generate.

Home

Getting going

Planning and observing

Imaging and processing

Science

Reference

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