Aither is a modern, software-based upgrade for Santa Barbara Scientific SM-3 and SM-4 SIMM-type seeing monitors. It operates as a direct successor to the ST-i-SM software that was originally supplied with and operated those systems.

While ST-i-SM provided highly-accurate seeing and transparency reports, there were limited ways to make its data available in real-time to other systems. Aither is a greenfield seeing analysis engine that provides analysis in much the same manner that ST-i-SM did, and does so with several modern capabilities not found on ST-i-SM or any other commercial seeing analysis system.

Features

Aither benefits from extensive experience in the fields of speckle interferometry, observatory operations, ASCOM and Alpaca development, and through supporting software services in a mission-critical operational environment. This is reflected throughout Aither’s extensive feature set.

Seeing Analysis
  • Advanced image analysis engine that provides near real-time running analysis of seeing conditions.
  • Primary seeing metric given in arcsecond FWHM and the Fried Parameter (r₀).
  • Atmospheric coherency time (τ₀), Rytov Variance, and Scintillation Index.
  • Sky transparency is calculated relative to a quality-gated SNR determination that is memorized.
  • Reacts appropriately to weather and other events that can degrade seeing analysis using a multi-layer data quality gate.
Data Outputs
  • Seeing data is graphed with customizable colors. Graph images can be periodically uploaded to a website via SFTP or FTP.
  • An ASCOM Alpaca Observing Conditions API endpoint serves the current seeing calculation via the StarFWHM property.
  • A Prometheus metrics API endpoint makes available all calculations for external polling and collection.
  • Can transmit all calculations as they are made in real-time to a time-series database that is compatible with the InfluxDB Line Protocol.
Operation
  • Aither runs natively on Windows 11 (x64) and Linux/Debian 13 trixie (x64 and ARM64).
  • Operates as a Windows Service and a Systemd service unit under Debian.
  • Installation and updates are provided as a Windows MSI package or Debian package.
  • The image analysis functions use the CPU’s SIMD instructions to shorten processing times.

Unihedron SQM Devices

Aither also supports Unihedron‘s SQM-LR, SQM-LU, and SQM-LE sky quality monitoring devices. When such a device is connected and configured, Aither will also display SQM statistics and generate graphs. SQM data also is made available through the same Alpaca, InfluxDB, and Prometheus facilities that seeing data is made available on.