App: CloudWatcher
Developer: GerSpatial
Genres: Weather, Education

CloudWatcher is a utility designed to enable Mac-based astronomers to interface with a hardware device called AAG CloudWatcher, available from Lunático Astronomia. This device measures a host of parameters vital for astronomers, such as cloudiness, rainfall and sky brightness. CloudWatcher can control a hardware switch in the hardware device which can trigger user-defined safety measures, such as closing an observatory roof.

The AAG CloudWatcher hardware ships with Windows software: CloudWatcher reproduces the main elements of its interface, and can interoperate with it in a Master/Remote architecture. But it also provides additional features.

It can interface to an external Sky Quality Meter: these SQM devices are made by Unihedron and are the standard for measuring sky darkness. CloudWatcher can interface directly to the model SQM-LE (ethernet-connected) or, via a new GerSpatial app in development (SQM Toolbox), to other models as well.

The latest version of the AAG CloudWatcher hardware also includes a light meter with very similar performance to the standard SQM system. CloudWatcher can display this or an external SQM, or both together on a two-trace plot for comparison.

In fact many of the standard plots have two traces, where the second trace provides related information (such as standard deviation of the sky temperature, which is useful for detecting thin, high level cloud, wind gust in addition to windspeed and dew point on the humidity graph).

CloudWatcher’s graphs are labelled with the axis variables and units and the horizontal time axis always uses natural round units.

An important feature of CloudWatcher is that it can interoperate with the Windows software provided with the AAG CloudWatcher device. The Transfer file allowing Master or Remote operation is compatible in both directions. It also generates a ClarityII (Boltwood) file 

CloudWatcher is compatible with all existing versions of the AAG CloudWatcher firmware.

Release notes:
Major new features in version 4.0:

- Added support for Dark Mode.

- Some major changes in the internal operations which makes the communications with the AAG CloudWatcher device very robust, with effectively no lost data.

- Added measurement of sensitive darkness level in magnitudes per square arc-sec (MPSAS) for those CloudWatcher models which support it.

- A new Summary tab has been added which gives a practical, colour-coded view of all environmental parameters at once. This view also provides a wide range of textural descriptions of conditions and gives the Bortle class of the associated sky quality measurement (from either or both the built-in Sky Quality sensor or a connected SQM device).

- Added an SQM parameter to the Clarity II format, with the mechanism to fill it with (a) built-in measurements, (b) measurement from a direct TCP/IP connection to a SQM-LE, (c) measurements from a file transfer (eg from SQM-Toolbox), (d) no SQM data. Note that the new TheSkyX ClarityII X2 plugin, by Rodolphe Pineau, is able to read this new parameter.

- Updated the sky temperature correction function to include the parameters K6 and K7, which existed in the Windows version for a long time. This is apparent in all the relevant interfaces, and particularly so in the “Edit” window, where the updated equations are now shown.

- Added a new graph tab to display atmospheric pressure, for those models which support it.

- Implemented an SQM Master/Remote architecture (which includes files generated by another GerSpatial app, SQM Toolbox) to harmonise SQM-LE access. In future, using SQM Toolbox, this will also allow USB models to contribute to CloudWatcher data.

- Added ability to select graph trace thickness.

- The External SQM measurement, if it exists, is included on the Summary tab, together with a description of the Bortle class of the measurement.


Minor or GUI improvements in version 4.0:

- Increased the size of the window to accommodate the extra features.
- Many improvements to the GUI.
- Added an additional section of the Limits tab to enable definition of textual descriptions of humidity conditions.
- The various transfer files are automatically enabled without using the associated checkbox. The checkbox remains functional in order to disable the transfer if necessary.
- Changed some of the default names for various conditions (e.g. “Bright” is now “Daylight”; “Light” is now “Twilight”)
- Slightly changed the default colours for graphs - these are only apparent after pressing “Reset”, which reverts to the defaults.
- Added dark red, in addition to bold, to the text in selected buttons on the Unsafe tab, to aid visibility.
- Relabelled the Find button in the Setup>Comms tab, to reflect its actual function: refreshing the list of serial ports.
- Added option to select rain Sensor type in the Settings->Device tab : this then determines the default calibration settings for the Rain Sensor.
- Enabled a choice of source for the ambient temperature measurement, for models which offer the appropriate sensors.
- Added the means to select parameters for both the main and secondary trace in the Brightness graph.
- Added the selection of LDR or Built-in SQM for the Brightness Limits tab.
- Removed AppleScript handlers for providing various data (changes in the Apple ecosystem mean they no longer work, and this cannot be resolved in the short-term).