ObservingConditions Class

Master Interfaces Reference

These green boxes in each interface member each have a link to the corresponding member definition in Master IObservingConditionsV2 Interface (external). The information in this Alpyca document is provided for your convenience. If there is any question, the info in ASCOM Master Interface Definitions (external) is the official specification.

class alpaca.observingconditions.ObservingConditions(address: str, device_number: int, protocol: str = 'http')

Bases: Device

ASCOM Standard IObservingConditions Interface

Provides measurements of meterological conditions as apply to astronomy. Determination of safe/unsafe is made by a separate SafetyMonitor device.

Initialize the ObservingConditions object.

Parameters:

  • address (str) – IP address and port of the device (x.x.x.x:pppp)

  • device_number (int) – The index of the device (usually 0)

  • protocol (str, optional) – Only if device needs https. Defaults to “http”.

Action(ActionName: str, *Parameters) → str

Invoke the specified device-specific custom action

Common to all devices

Parameters:

  • ActionName – A name from SupportedActions that represents the action to be carried out.

  • *Parameters – List of required parameters or [] if none are required.

Returns:

String result of the action.

Raises:

Note

  • This method, combined with SupportedActions, is the supported mechanic for adding non-standard functionality.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for Action(), find this specific device’s specification, and see Action() there.

CommandBlind(Command: str, Raw: bool) → None

Transmit an arbitrary string to the device and does not wait for a response.

Common to all devices

Parameters:

  • Command – The literal command string to be transmitted.

  • Raw – If true, command is transmitted ‘as-is’. If false, then protocol framing characters may be added prior to transmission.

Raises:

Attention

Deprecated, will most likely result in NotImplementedException

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for CommandBlind(), find this specific device’s specification, and see CommandBlind() there.

CommandBool(Command: str, Raw: bool) → bool

Transmit an arbitrary string to the device and wait for a boolean response.

Common to all devices

Returns:

The True/False response from the command

Parameters:

  • Command – The literal command string to be transmitted.

  • Raw – If true, command is transmitted ‘as-is’. If false, then protocol framing characters may be added prior to transmission.

Raises:

Attention

Deprecated, will most likely result in NotImplementedException

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for CommandBlind(), find this specific device’s specification, and see CommandBlind() there.

CommandString(Command: str, Raw: bool) → str

Transmit an arbitrary string to the device and wait for a string response.

Common to all devices

Returns:

The string response from the command

Parameters:

  • Command – The literal command string to be transmitted.

  • Raw – If true, command is transmitted ‘as-is’. If false, then protocol framing characters may be added prior to transmission.

Raises:

Attention

Deprecated, will most likely result in NotImplementedException

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for CommandString(), find this specific device’s specification, and see CommandString() there.

Connect() → None

Connect to the device asynchronously.

Common to all devices

Returns:

Nothing

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • Non-Blocking Use Connecting to indicate completion.

  • Natively present only in Platform 7 (2024) devices, but this library emulates Connect()/Disconnect()/Connecting mechanic for older devices.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for Connect(), find this specific device’s specification, and see Connect() there.

Disconnect() → None

Disconnect from the device asynchronously.

Common to all devices

Returns:

Nothing

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • Non-Blocking Use Connecting to indicate completion.

  • Natively present only in Platform 7 (2024) devices, but this library emulates Connect()/Disconnect()/Connecting mechanic for older devices.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for Disconnect(), find this specific device’s specification, and see Disconnect() there.

Refresh() → None

Forces the device to immediately query its attached hardware to refresh sensor values

Raises:

Master Interfaces Reference

ObservingConditions.Refresh() (external)

SensorDescription(SensorName: str) → str

Description of the sensor providing the requested property

Parameters:

SensorName – A string containing the name of the ObservingConditions meterological property for which the sensor description is desired. For example “WindSpeed” (for WindSpeed) would retrieve a description of the sensor used to measure the wind speed.

Raises:

Master Interfaces Reference

ObservingConditions.SensorDescription (external)

TimeSinceLastUpdate(SensorName: str) → str

Elapsed time (sec) since last update of the sensor providing the requested property

Parameters:

SensorName – A string containing the name of the ObservingConditions meterological property for which the time since last update is desired. For example “WindSpeed” (for WindSpeed) would retrieve the time since the wind speed was last updated by its sensor.

Raises:

Master Interfaces Reference

ObservingConditions.TimeSinceLastUpdate (external)

property AveragePeriod: float

(read/write) Gets And sets the time period (hours) over which observations will be averaged

Raises:

  • InvalidValueException – If the value set is out of bounds for this device. All devices must accept 0.0 to specify that an instantaneous value is to be made available.

  • NotConnectedException – If the device is not connected

  • DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • AveragePeriod returns the time period (hours) over which sensor readings will be averaged. If the device is delivering instantaneous sensor readings this property will return a value of 0.0.

  • Though discouraged in the specification, possible you will receive an exception if you read a sensor property when insufficient time has passed to get a true average reading.

Master Interfaces Reference

ObservingConditions.AveragePeriod (external)

property CloudCover: float

Amount of sky obscured by cloud (0.0-1.0)

Raises:

Master Interfaces Reference

ObservingConditions.CloudCover (external)

property Connected: bool

(Read/Write) Retrieve or set the connected state of the device.

Common to all devices

Set True to connect to the device hardware. Set False to disconnect from the device hardware. You can also read the property to check whether it is connected. This reports the current hardware state. See Notes below.

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • The Connected property sets and reports the state of connection to the device hardware. For a hub this means that Connected will be True when the first driver connects and will only be set to False when all drivers have disconnected. A second driver may find that Connected is already True and setting Connected to False does not report Connected as False. This is not an error because the physical state is that the hardware connection is still True.

  • Multiple calls setting Connected to True or false will not cause an error.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for Connected, find this specific device’s specification, and see Connected there.

property Connecting: bool

Returns True while the device is undertaking an asynchronous Connect() or Disconnect() operation.

Common to all devices

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • Use this property to determine when an (async) Connect() or Disconnect() has completed, at which time it will transition from True to False.

  • Natively present only in Platform 7 (2024) devices, but this library emulates Connect()/Disconnect()/Connecting mechanic for older devices.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for Connecting, find this specific device’s specification, and see Connecting there.

property Description: str

Description of the device such as manufacturer and model number.

Common to all devices

Raises:

  • NotConnectedException – If the device status is unavailable

  • DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • This describes the device, not the driver. See the DriverInfo property for information on the ASCOM driver.

  • The description length will be a maximum of 64 characters so that it can be used in FITS image headers, which are limited to 80 characters including the header name.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for Description, find this specific device’s specification, and see Description there.

property DeviceState: List[dict]

List of key-value pairs representing the operational properties of the device

Common to all devices

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for DeviceState, find this specific device’s specification, and see DeviceState there.

property DewPoint: float

Atmospheric dew point temperature (deg C) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.DewPoint (external)

property DriverInfo: List[str]

Descriptive and version information about the ASCOM driver

Common to all devices

Returns:

Python list of strings (see Notes)

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • This describes the driver not the device. See the Description property for information on the device itself

  • The return is a Python list of strings, the total length of which may be hundreds to thousands of characters long. It is intended to display detailed information on the ASCOM (COM or Alpaca) driver, including version and copyright data. . To get the driver version in a parse-able string, use the DriverVersion property.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for DriverInfo, find this specific device’s specification, and see DriverInfo there.

property DriverVersion: str

String containing only the major and minor version of the driver.

Common to all devices

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • This must be in the form “n.n”. It should not to be confused with the InterfaceVersion property, which is the version of this specification supported by the driver. Note: on systems with a comma as the decimal point you may need to make accommodations to parse the value.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for DriverVersion, find this specific device’s specification, and see DriverVersion there.

property Humidity: float

Atmospheric relative humidity (0-100%) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.Humidity (external)

property InterfaceVersion: int

ASCOM Device interface definition version that this device supports.

Common to all devices

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • This is a single integer indicating the version of this specific ASCOM universal interface definition. For example, for ICameraV3, this will be 3. It should not to be confused with the DriverVersion property, which is the major.minor version of the driver for this device.

  • This value is cached internally after first retrieval since it is repeatedly used if emulating Connect/Disconnect semantics on older (pre - Platform 7) devioces.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for InterfaceVersion, find this specific device’s specification, and see InterfaceVersion there.

property Name: str

The short name of the driver, for display purposes.

Common to all devices

Raises:

DriverException – If the driver cannot successfully complete the request. This exception may be encountered on any call to the device.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for Name, find this specific device’s specification, and see Name there.

property Pressure: float

Atmospheric pressure (hPa) at the observatory altitude

Raises:

Note

Not “corrected to sea level” as often encountered in weather reports. The ConvertPressure() method may be used to get “sea level” pressure

Master Interfaces Reference

ObservingConditions.Pressure (external)

property RainRate: float

Rain rate (mm/hr) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.RainRate (external)

property SkyBrightness: float

Sky brightness (Lux) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.SkyBrightness (external)

property SkyQuality: float

Sky quality (mag per sq-arcsec) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.SkyQuality (external)

property SkyTemperature: float

Sky temperature (deg C) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.SkyTemperature (external)

property StarFWHM: float

Seeing (FWHM in arc-sec) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.StarFWHM (external)

property SupportedActions: List[str]

The list of custom action names supported by this driver

Common to all devices

Returns:

Python list of strings (see Notes)

Raises:

DriverException – An error occurred that is not described by one of the more specific ASCOM exceptions. The device did not successfully complete the request.

Note

  • This method, combined with Action(), is the supported mechanic for adding non-standard functionality.

  • SupportedActions is a “discovery” mechanism that enables clients to know which Actions a device supports without having to exercise the Actions themselves. This mechanism is necessary because there could be people / equipment safety issues if actions are called unexpectedly or out of a defined process sequence. It follows from this that SupportedActions must return names that match the spelling of Action() names exactly, without additional descriptive text. However, returned names may use any casing because the ActionName parameter of Action() is case insensitive.

Master Interfaces Reference

Alpyca uses a common Device class but this is not available in the ASCOM Master Interface Definitions (external). To see the reference info for SupportedActions, find this specific device’s specification, and see SupportedActions there.

property Temperature: float

Atmospheric temperature (deg C) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.Temperature (external)

property WindDirection: float

Direction (deg) from which the wind is blowing at the observatory

Raises:

Note

  • Meterological standards Wind direction is that from which the wind is blowing, measured in degrees clockwise from true North=0.0, East=90.0, South=180.0, West=270.0 If the wind velocity is 0 then direction is reported as 0.

Master Interfaces Reference

ObservingConditions.WindDirection (external)

property WindGust: float

Peak 3 second wind gust (m/s) at the observatory over the last 2 minutes

Raises:

Master Interfaces Reference

ObservingConditions.WindGust (external)

property WindSpeed: float

Wind speed (m/s) at the observatory

Raises:

Master Interfaces Reference

ObservingConditions.WindSpeed (external)