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Version 6.5 SP1


In line with previous Platform installers, 6.5 SP1 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 6.5 SP1 - For Everyone
  • Platform:
    • The Platform and Developer installers are now code signed.
    • The Platform and Developer installer executable names now include SP1 to clearly differentiate them from the Platform 6.5.0 installers.
    • The Platform installer requires write access to the user's Documents folder and, if this is not permitted, will recommend that installation is abandoned. Some situations where write access is known to be restricted are:
      • Microsoft's Controlled Folder Access capability is enabled.
      • An anti-ransomware program has restricted access.
      • Windows is run in a Parallels virtualisation environment under MacOS and the Platform installer is located in the Documents folder that maps directly to the user's MacOS Documents folder. Running the installer from a "native" Windows folder within the Parallels virtual machine, e.g. a folder on the Windows C: drive, works fine.
    • Platform simulators and hubs now have assembly version numbers to reflect the service pack release.
  • The Hub, Pipe, POTH and ASCOM Dome driver profiles are now backed up by the installer before removal. This preserves configuration information for re-use in Device Hub, or the legacy drivers if these are reinstalled at a later date. The configuration information is stored in the "Platform Driver Backups" Profile key and can be viewed through Profile Explorer.
  • Device Hub
    • Side Of Pier and Destination Side Of Pier will now be calculated by Device Hub if not available from the downstream driver.
    • The dome shutter can now be opened and closed when slaved.
    • Exceptions are now trapped and logged during dome slaving calculations.
    • Improved RotarySlider control use to support non-zero minimum value and to allow both minimum and maximum values to be selected by dragging the rotary dial.
    • The configuration persistence mechanic now tolerates a corrupted settings file.
    • The dome setup and telescope direct slew dialogues now uses text boxes instead of value controls.
    • The main window now displays help on how to expand all three expanders when in expansion mode.
    • There is now a confirmation message when the set park button is clicked.
  • All references to the Yahoo ASCOM Talk forum have been replaced with references to the new Groups.IO forum.
  • All links referencing the web site now use HTTPS instead of HTTP.
  • DeltaT predictions, good to December 2021, have been revised based on the latest IERS predictions.
  • The SOFA component has been updated to use the latest IAU 21st July 2020 - Version 16 SOFA release.
  • Chooser Properties Button - detailed failure information will now be provided if a driver does not connect correctly.
  • The Camera simulator description now reflects that it supports ICameraV3.
Issues Fixed - Platform
  • A serious bug was introduced in the Astrometry.Transform class during Platform 6.5 implementation, which prevented a single instance from being used for multiple transforms. The bug has been fixed and Transform now works as it did in Platform 6.4.
  • Writing to the Alpaca Dynamic Client Camera.Offset property now works correctly.
  • In October 2020, NASA disabled anonymous access to its earth rotation data files and this broke the Platform's update capability. This release restores functionality by mirroring the files on the ascom-standards web site and downloading them from there.
  • Parsing of earth rotation data files is more robust when files do not contain expected data.
  • Corrected a typo in the message given if a disconnect fails when using the Choose and Connect to Device form. Thanks Marco!
  • The Platform installer now:
    • Works properly on machines whose PC Name contains a space character.
    • Handles unregistering drivers more gracefully.
    • Checks that the Windows Task Scheduler is enabled before attempting to create the earth rotation data update scheduled task.
    • Sets the required registry Profile store ACL on every install rather than assuming that it is correctly set when upgrading from a previous Platform version. Access to the Profile store is confirmed after setting the ACL and any issues will be reported by the installer.
    • Removes simulator COM entries when uninstalled.
    • Lists errors more clearly on the closing screen.
  • Device Hub
    • Improved support for locales that use comma as the decimal separator.
    • Profile settings will now be preserved when upgrading.
    • SideofPier exceptions will now be forwarded to the client.
    • SlewDomeToAzimuth now responds with the correct exception if an invalid azimuth value is requested.
    • The telescope Slewing flag is now correctly maintained when the mount is pulse guiding.
    • Telescope set park functionality now persists the set value.
  • Profile Explorer - Renaming a key now retains its subkeys and their values.
  • Diagnostics:
    • Now correctly reports the Windows 10 operating system version.
    • A rare exception that occurred when recursing registry keys has been fixed.
Retired Components

The following Platform 5 hubs have been retired in Platform 6.5 and are 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 6.5 SP1 - For Developers
  • Comments in the driver templates are now clearer on how to implement the CommandXXX methods.
  • The ObservingConditions driver template code for the TimeSinceLastUpdate and SensorDescription methods has been refreshed to ensure that the VB and C# templates have identical functionality.
  • Improved TraceLogger messaging if an instance is used after being disposed.
Issues Fixed - Developers
  • Recent versions of Visual Studio have started trapping NullReferenceExceptions that previously were not caught. Utilities.Profile has been recoded to avoid these.
  • The CloudCover property has been added to the TimeSinceLastUpdate and SensorDescription methods in the ObservingConditions driver template.
  • The developer installer repair option no longer loops indefinitely.
  • DriverAccess now returns PropertyNotImplementedExceptions for the new "offset" properties when an ICameraV2 driver is in use.
  • DriverAccess.Camera now implements interface ICameraV3 instead of ICameraV2.
  • The new IRotatorV3 members in DriverAccess now return better formatted "not implemented" messages when an IRotatorV2 driver is in use.
  • Clients will now receive the correct type of NotImplementedException (PropertNotImplementedException or MethodNotImplementedException) when Alpaca devices report that a member is not implemented.
Breaking Changes (For Developers) in Platform 6.5
  • 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 6.5 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 6.5 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.