Click or drag to resize

Version 6.6


In line with previous Platform installers, 6.6 is a cumulative release that contains all enhancements and fixes from previous Platform releases and service packs. The Platform environment pre-requisites are listed here Platform Prerequisites.

Key Changes in 6.6 - For Everyone
  • The Alpaca Dynamic Camera Client now supports the ImageBytes protocol.
  • Telescope Simulator:
    • Client supplied TelescopeAxes values are validated before use.
    • The Tracking state is restored after Park and Home are called.
  • Camera Simulator:
    • PulseGuide directions are validated before use.
  • Device Hub
    • Added a setting to keep Device Hub as the topmost application.
    • Polling frequency is increased for the duration of a slew.
    • Implements a stricter interpretation of the Park command requirements.
  • The mechanic to bring Simulator setup dialogues to the front of screen has been made more reliable.
  • ObservingConditions Simulator and ObservingConditions Hub test applications
    • Redundant "Chooser" buttons have been removed.
    • Automatic polling can now be toggled on and off.
Issues Fixed in 6.6 - Platform
  • Chooser drop-down list management has been refined to avoid an issue in AllSkEye.
  • NOVAS ephemeris calculations have been made more reliable.
  • Registry handles are now properly released in AstroUtils and EarthRotationParameters.
  • Diagnostics - A video utilities test failure that only occurred on Windows 7 64bit when the text size was above 100% has been fixed.
  • The Dome Simulator now throws ASCOM DriverExceptions when appropriate rather than using the original VB6 Err.Raise mechanic.
  • Dynamic Clients
    • The Camera, Dome and Focuser Dynamic Clients now send every parameter value in the Invariant Culture, as required by the Alpaca specification, this avoids parsing issues in locales where the decimal separator is not the point character.
    • All clients are now tolerant of missing "Value" and ErrorMessage fields in returned responses.
  • Platform Installer
    • The mechanic used to set the ASCOM Profile registry ACL has been improved to avoid installation issues observed on some PCs.
    • The mechanic used to find the localised name of the BUILTIN\USERS group has been changed to avoid installation issues that a small number of users experienced if their WMI installations were not fully functional.
    • All installer support executables are now code signed to avoid issues with some anti-virus programs.
  • Device Hub
    • Telescope: Slewing remains true if an associated Dome is still in motion.
    • Telescope: The driver rejects method calls when the scope is being parked or unparked.
    • Telescope: Corrected logic to support aborting a fixed slew.
    • Telescope: Ensure that a telescope side-of-pier is only calculated for a German Equatorial mount.
    • Telescope: Corrected expected answer for ChangeParkState MessageBox from OK to Yes.
    • Dome: Slaving is more resilient.
    • Dome: Fixed shutter position reporting and disabled Open/Close Shutter button when CanSetShutter is false.
  • The RemoveASCOM component is now code signed.
  • Improved handling when Alpaca devices report errors when calling the ImageArray, ImageArrayVariant, TrackingRates and AxisRates properties.
Retired Components

The following Platform 5 hubs were retired in Platform 6.5 and replaced by the new Device Hub. We strongly recommend that you switch over to using the Device Hub because these components will be removed in a future release.

  • POTH
  • Hub
  • Pipe
  • Dome Control Hub
Key Changes in 6.6 - For Developers
  • A SitePressure property has been added to the Transform component to improve the accuracy of refraction calculations.
  • The SOFA component has been updated to the latest SOFA 18.0 release, 12th May 2021.
  • The Local Server Driver Generator now creates a project that uses a more secure mechanic to locate drivers that are to be served.
    • Drivers are now held as classes within the local server executable rather than as separate DLL's. This eliminates the need to dynamically search for and load driver DLLs at run-time, a mechanic which could have been abused to load malicious code.
    • The local server template now creates a single project containing both the local server and a single driver.
    • Instructions on how to add further drivers, if required, are included in the ReadMe that appears on creation of the local server.
  • The comments in the Switch template have been expanded and clarified.
  • Camera.ImageArray element ordering has been clarified.
Issues Fixed in 6.6 - For Developers
  • Links to support forums in the developer templates have been updated to reference the Groups.Io forum.
  • An inconsistency in the Camera.SensorName documentation has been resolved.
Breaking Changes (For Developers) in Platform 6.6
  • The ASCOM.Utilities.Units “Fahrenheit” member has been deprecated in favour of the correctly spelled “Fahrenheit” member. This will not affect compiled programs but will result in warnings when the code is next compiled.
Note Note

Driver and application developers: In order to maintain a healthy code base, some tidying up is planned for the next major update and details of the changes are given in the Deprecated Features section below. Please will you review this and update your applications and drivers as advised; these changes are not currently scheduled for introduction before Q2 2020 at the earliest. In the meantime service packs will be issued as required to correct bugs.

Known Limitations - Developers
  • The components in the Astrometry.NOVAS namespace are fully usable from .NET languages but are not fully accessible through COM from scripting languages because a number of parameters are passed by reference or use structures that do not pass across the COM interface. Two work rounds are available:
    1. Use the Transform component in the ASCOM.Astrometry.Transform namespace, it is fully COM compatible.
    2. Create your own COM presentation component that encapsulates the SOFA or NOVAS 3.1 functions that you require and presents them in a COM compatible fashion to suit your needs. This component can them be consumed by your scripting application.
Deprecated Capabilities (For Developers)
  • The ASCOM.Astrometry namespace of the Platform has become overcrowded with components that have similar capabilities but that differ in small ways from each other (e.g. NOVAS2, NOVAS2COM, NOVAS3, NOVAS3.1). The recent realisation that some NOVAS routines use iterative algorithms that can fail, when in very close proximity to the poles, led to a search for an alternative and the SOFA Library was found to be an actively maintained and authoritative choice.

    The addition of a SOFA component brings the number of high precision astronomy libraries distributed within the Platform to 8! To reduce the maintenance burden, SOFA will become the primary high precision library for astronomical computing distributed with the ASCOM Platform and dependence of Platform components on NOVAS will be removed. However, the NOVAS routines provide functionality that is not present in SOFA e.g. major and minor planet ephemerides and consequently the NOVAS 3.1 component will continue to be distributed with the Platform.

    The following NOVAS components will be removed from the Platform installation at the next major update:

    • NOVAS2
    • NOVAS3

    PLEASE NOTE: The Kepler and NOVASCOM components were flagged as deprecated in previous Platform releases but will now be retained following feedback from developers.

  • The following VB6 based simulators and hubs will be removed from the Platform at the next major update. These drivers were moved to a "bug-fix only" maintenance mode when Platform 6 was released and are becoming increasingly out of step with their .NET counterparts, which are fully integrated into the Platform code base.




    Camera Simulator


    Replace use of the CCDSimulator.Camera ProgID with ASCOM.Simulator.Camera, which will invoke the "Camera V2 simulator

    Dome Simulator


    Replace use of the DomeSim.Telescope ProgID with ASCOM.Simulator.Dome, which will invoke the "Dome Simulator .NET" driver.

    Filter Wheel Simulator


    Replace use of the FilterWheelSim.FilterWheel ProgID with ASCOM.Simulator.FilterWheel, which will invoke the "Filter Wheel Simulator [.NET]" driver.

    Focuser Simulator


    Replace use of the FocuserSim.Focuser ProgID with ASCOM.Simulator.Focuser, which will invoke the "ASCOM Simulator Focuser Driver" driver.

    Switch Simulator


    Replace use of the SwitchSim.Switch ProgID with ASCOM.Simulator.Switch, which will invoke the "ASCOM SwitchV2 Simulator Driver" driver.

    Telescope Simulator


    Replace use of the ScopeSim.Telescope ProgID with ASCOM.Simulator.Telescope, which will invoke the "Telescope Simulator for .NET" driver.

    Pipe hub

    Pipe.Telescope, Pipe.Dome, Pipe.Focuser

    Replace with Device Hub - ASCOM.DeviceHub.Telescope, ASCOM.DeviceHub.Dome, ASCOM.DeviceHub.Focuser

    Hub hub

    Hub.Telescope, Hub.Dome, Hub.Focuser

    Replace with Device Hub - ASCOM.DeviceHub.Telescope, ASCOM.DeviceHub.Dome, ASCOM.DeviceHub.Focuser

    POTH hub

    POTH.Telescope, POTH.Dome, POTH.Focuser

    Replace with Device Hub - ASCOM.DeviceHub.Telescope, ASCOM.DeviceHub.Dome, ASCOM.DeviceHub.Focuser

    ASCOM Dome Control hub

    ASCOMDome.Dome, ASCOMDome.Telescope

    Replace with Device Hub - ASCOM.DeviceHub.Telescope, ASCOM.DeviceHub.Dome

Platform Prerequisites

Platform 6.6 requires the following .NET framework version and library:

  • .NET Framework 4.8
  • For WIndows 8 and Windows 10 the .NET Framework 3.5 option must be enabled in Control Panel / Programs and Features / Turn Windows Features On and Off
  • Visual C++ 16.0 libraries (these are provided by the Platform installer if required)

While previous Platforms required .NET Framework 4.0, Platform 6.6 requires that .NET Framework 4.8 is installed on your PC. This change is to enable Platform components to take advantage of new features introduced after Framework 4.0 was released and to put the Platform onto what Microsoft has flagged as the last release of .NET Framework.

The installer will advise you if your PC does not have the required support and will request that you install or enable it before continuing with the installation. Microsoft Download Centre

The Platform installer will provide or update the C++ 16 libraries if they are not already present on your PC or are not current.