Introduction

This application uses a set of objects to represent the devices and instruments that astronomers build into systems and ultimately into global networks of observing resources. The intent is to recognse that some objects are almost mandatory as a relation to another object - e.g. a telescope OTA almost always has a dew heater and a focuser when setup for imaging but an observatory may have a flat field device for all the contained mounts as well as or instead of on a per individual OTA basis. So there is a degree of default hierarchy about the relationships but also the ability to add in devices as related objects at any level.

Objects

• Sites are the geographic locations where services are provided from
• Stations are pools of resource within a site. For example a station may have three sites in its boundary, each site supports 2 stations of where each station comprises an observatory building and an external, naked mount point.
• Mounts are the pieces of hardware that carry telescopes. Most will track, some may be fixed. In ASCOM terms this will be a Telescope object, each of their own type and horizon context, even if they share the same building.
• Optical Tube Assemblies (OTAs) are the collecting devices which are mounted on the mount. There maybe several. They are assumed parallel but could be at multiple orientations to the main mount axis. (Gulp!)
• Ports are the points on an OTA to which instruments are connected. Typically there is at least one port per OTA but there could be several via focal plane sharing or OAG/ONAG splitting. Each port may have an an associated instrument and function. So ports are the means of supporting multiple instruments on a single telescope or data collecting device ( moving from being optically-biased here) and supporting guiding while imaging.
• Camera is an Alpaca or Indi compliant imaging or otherwise data collection device on a port. It may be a guider.
• Dew-heater is an Alpaca or Indi compliant electronic dew heater with local or remote conditions adjustment.
• Cover-calibrator - is a cover for the OTA that support flat fielding or just aperture sealing.
• Focuser is an electronic remote focusing device for the port.
• Switch is an lectronic device for turning electric hardware on and off, sensing in some cases and PWM in others.
• Spectrometer - ultimately we also neeed a spectrometer device which will comprise a number of sub-devices.

Services

Four special services are proposed currently

• Auto-guiding
• Auto-focusing
• Auto-flats generation
• Auto-calibration

Containers

Sites contain stations and have administrative Users.

Stations contain 1 or more mounts and have an enclosure type with associated horizon Stations may also contain Flat field devices and switches.

Mounts contain one or more OTAs, one or more switches

Collections

The core data structure is a graph of nodes with each T node having associated devices defined in a node list. The gui client and the server schedule operator add a default or custom operating model to relate the objects for instrument or visual observing.

Allocation

Observation Profiles

An observation type is performed by following a profile which describes the steps used to perform the observation. An observation or instrument can have a custom profile assigned to override the default which will be operated by preference.

Configuration

The configuration is held entirely within the Server in the form of an XML file describing the configuration graph. The GUI client needs a very simple config provided at start up which is the hostname of the server and the port.

Testing

Testing is done by object type