Orionis Group
Two mount conventions
Analyze altitude–azimuth and equatorial observations, with latitude specified for HA/Dec mode.
Pointing analysis, with the details in view.
First-order and rigorous fitting
Compare the linear approximation with an iterated Bayesian MAP fit using full rotations.
Useful diagnostics
Inspect fitted coefficients, uncertainties, correlations, residuals, and convergence. Add your own terms in the editable additional-term file.
New in 2.1.1
Evaluate an existing model
Check a coefficient file against pointing observations without fitting new coefficients.
Compare residuals
See first-order and rigorous statistics and export the residuals of every star to CSV.
Check another observation set
Use the --external option when the coefficients were fitted on other observations. It applies the corresponding population-SD convention.
Scientific improvements retained from 2.1.0
Corrected pointing terms
FO, NRX, NRY and HA/Dec TX are corrected, with a consistent coefficient sign convention.
Read the upgrade guidanceReadable term catalogue
Choose model terms with their formulas, conventions and model steps in view.
Browse the term catalogueUse your fitted model
Supplied Python and C modules, also usable from C++, apply the fitted model in a telescope control system.
Control-system guidanceUpgrading from 2.0.0? Review the coefficient and refitting changes before using an existing model. Keep the coefficient file, term definitions and control-system module on the same version.
WINDOWS · 64-BIT
Download Pytheia 2.1.1
Windows package version 2.1.1. Maintenance build 26L33 includes the coordinate-loading correction.
Currently available for Windows 64-bit. Contact Orionis to express interest in Linux or macOS availability.
The complete package includes its own Python runtime and dependencies. Extract the entire ZIP before running it. A separately issued signed evaluation license is required.
Verify the download
Exact download size: 107,975,807 bytes.
In PowerShell, run:
Get-FileHash .\Pytheia211_Evaluation_WINDOWS.zip -Algorithm SHA256Compare the result with this SHA-256:
06C4CB3CAEFF47492340635E5EE07FCFF0CE8207371B9562F7765168C5E69702PERSONALIZED EVALUATION
Request your 30-day license.
Email Orionis with the name to appear after Licensed to. This may be an individual or an institution. For an institution, include a contact person and reply address.
Open license-request emailThis opens your email application; you review and send the request. If no email app opens, write to contact@orionisgroup.com with the subject “Pytheia 2.1.1 evaluation request”.
How the period works
30 UTC calendar days, beginning on the UTC issuance date. Expiry is at 00:00 UTC on the exclusive expiry date shown in the signed license.
The clock starts on issuance, not installation or first use. Orionis supplies the signed license, signature, and agreement identifying your name and period.
Commercial licensing and support arrangements are handled separately through Orionis.
Start with the reference dataset.
The bundled synthetic example has 120 observations and eight fitted terms. Its converged rigorous total RMS is 2.5608 arcseconds. This is a reference result for that dataset, not an accuracy guarantee for another telescope.
Validation history
The 2.1.0 baseline passed 44 scientific self-tests and Python, C and C++ control-system comparisons across 131 models each. In 2.1.1, Windows fitting and both evaluation modes passed on the bundled 120-star Az/El example. Evaluation exported identical residuals with and without --external and left the coefficients unchanged. The final Windows ZIP passed inventory, CRC and archived-file byte verification.
Coordinate-loading correction
Maintenance build 26L33 corrects the identified pandas chained-assignment warning during coordinate loading. All 50 protected-loader cases passed across Az/El and HA/Dec. Fitting and both evaluation modes also passed through the Windows executable on the bundled 120-star Az/El example without the diagnostic, retaining the reference residual results. These checks do not establish full fitting or evaluation coverage for HA/Dec or arbitrary inputs.
Questions before you start?
Do I need to install Python?
No. The Windows package includes an isolated Python runtime and the required dependencies. Keep every package folder together.
Where do I change the model settings?
Edit settings.ini. You can also pass a different settings file to Pytheia200.exe. The Windows setup guide gives both commands.
What happens when the license expires?
Licensed calculations stop. The evaluation agreement describes your rights and obligations, including retention of your data, independently written terms, and generated reports.
Are older downloads still available?
Yes. Pytheia100 v1.1.0 and v1.0.0 remain on their previous-release pages.