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Connections and Applications

This section provides an overview of how applications on the various supported devices connect to OnStep and how to configure those connections.


The physical connection

The basic connection is on OnStep's USB/Serial port.

  • This is usually how the OnStep ASCOM driver talks to OnStep and is often the same serial port where you uploaded the OnStep Sketch to.
  • This allows for only one application to connect at a time.  Note however using ASCOM or INDI overcomes this limitation and allows sharing the one connection.
  • This connection is generally regarded as reliable and fast (low latency.)
  • By default OnStep uses 9600 baud, though some devices disregard the baud rate and communicate at much higher speeds (Teensys, some STM32.)
  • Tip: some boards are prone to being reset when opening the USB/Serial port.  This is due to the automatic firmware upload mechanism designed for the Arduino IDE.  In the case of my ASCOM driver it takes steps (and has additional user settings) to prevent this from happening in most cases; but due to the near infinite variety of boards/knockoffs/etc. some still reset.  Sometimes this causes problems, sometimes not.  Workarounds range from modifying h/w to disable the mechanism to using other connection methods.

A basic direct wireless connection is Bluetooth/Serial.

  • This allows for only one application to connect at a time.  Note however using ASCOM or INDI overcomes this limitation and allows sharing the one connection.
  • Each Bluetooth Client must be paired with the Server.  The typical Android phone or tablet has a Bluetooth pairing facility in the settings menu to accomplish this.  Other devices/operating systems have similar facilities for pairing.
  • Once paired there is sometimes a unique Bluetooth Address that must be set in the application that will be talking to OnStep.  My Android App provides a list of addresses in its connection activity to accomplish this setup.  In other cases (Windows) the Bluetooth device becomes a virtual serial port which works like any other serial port.
  • Sometimes problematic to get connections (due to software on PCs mostly) and a bit slower than USB/Serial.
  • Doesn't work with iOS devices (iPhone/iPad) due to their lack of support for Bluetooth SPP (Serial Port Profile.)

The most flexible connection to OnStep uses WiFi/Ethernet (using the Smart Web Server.)

  • Several devices and applications can connect at the same time.
  • Typically has higher latency than other options, especially for WiFi.
  • For WiFi in Access Point mode (the default):
    • The default SSID is "ONSTEP" with password "password".
    • The default address is 192.168.0.1
    • The default password to edit WiFi settings is also "password".
  • For Ethernet (and WiFi in Station mode):
    • Configure the IP Address, Gateway, and Subnet for your network in "Extended.config.h".
      • Remember to use the "Extended.config.h" facility to wipe NV if mistaken settings don't allow you to connect as the settings you specify are defaults (applied on first upload only and changed by connecting to the website.)
  • The Smart Web Server provides a website (port 80) and two command channels.  The port 9999 command channel can host several clients simultaneously.  The port 9998 persistent command channel can host just one client, but it's compatible with more applications (described below.)  The latest version of the SWS adds two other persistent command channels at 9997, and 9996.

The Application connection

There are three primary methods applications use to talk to OnStep using LX200 protocol across the above mentioned interfaces:

  • ASCOM (on Windows)
    • ASCOM provides a standardized Astronomy application specific interface which then passes the traffic to OnStep across IP (WiFi or Ethernet) or USB/Serial or Bluetooth/Serial.
    • There is usually a "Chooser" window in any ASCOM aware application where you can access the ASCOM driver setup dialog.
    • The OnStep ASCOM driver must be installed separately after the ASCOM platform is installed.
  • INDI (on Linux/OSX mainly)
    • INDI provides a standardized Astronomy application specific interface which then passes the traffic to OnStep across USB (Serial), IP (WiFi or Ethernet) or Bluetooth (Serial).
    • The OnStep INDI driver is built-into the INDI Library , so it can be used on Linux from KStars or other INDI supporting clients.
      • For support for OnStep INDI, check the OnStep topic on the INDI forum.
        • If you are a developer and want to modify the INDI driver, or want to review/learn more on the code for the INDI driver, please refer to the OnStep INDI driver on GitHub.
      • INDI can control OnStep over USB/Serial or WiFi using port 9998.
  • Direct LX200 protocol (Windows, Linux, OSX, iOS, Android)
    • This is a common command set used to talk to OnStep across WiFi/Ethernet or USB/Serial or Bluetooth/Serial.)
    • An OnStep Python API is available for those who want to write test scripts, automate certain tasks, ...etc.

The Smart Web Server (SWS) Website

If using the Smart Web Server to provide WiFi or Ethernet command channels there is also a website that allows setup and control of OnStep.

This provides what amounts to a universal setup, control, and monitoring option that can work on pretty much any operating system.  Specifically iOS devices like the iPhone and iPad don't have an OnStep App.  Also, some functions provided by the website have no equivalent even in ASCOM, INDI, etc.  Like encoder control and mount axis setup, for those the website is really the only option.




 


The Applications

 Windows

  • Sky Planetarium my planetarium software, uses ASCOM and has a higher level of integration with OnStep than any other option.



  • SkyChart (also known as Cartes du Ciels or CdC) is a well respected planetarium program, not as nice to look at as Stellarium, but very flexible.
  • Stellarium is another frequently recommended choice.
  • NINA is a great astro imaging application, better than some of the commercial offerings in my opinion.
  • PHD2 is the defacto standard auto-guiding software.

 

 Linux

Any planetarium that supports INDI should be able to interface to OnStep. The following are known to work to various degrees.

  • KStars provides the most integrated imaging setup for Linux. Note that you should not install KStars from your distro's repository. Rather, install it from Jasem Mutlaq's PPA repositories, per these instructions. That way, you also get the latest INDI and Ekos sequence capture software.
  • SkyChart (also known as Cartes du Ciels or CdC) has an excellent planetarium that runs on Linux and interfaces to OnStep over INDI. The same author also provides CCDciel which is an image capture system.
  • Stellarium also runs on Linux, and is available in most distro repositories. It can interface with OnStep. Reduce the parameter maximum_fps to 3 in config.ini to avoid excessive CPU usage.
  • AstroBerry is a bundled image for the Raspberry Pi that includes KStars/Ekos/INDI as well as CdC and CCDciel .
  • OnStep Python API is a pure Python interface that works over USB (Serial) or WiFi/Ethernet. It is intended as a testing platform to make test sequences easier to repeat over and over.

Android

  • OnStep Controller2
    My Android App can connect to OnStep over Bluetooth or WiFi.
    • If using Bluetooth be sure to enable Bluetooth on your device and pair with OnStep first.
    • From my App's main screen, press the menu button and select Connection.
      • To connect to OnStep with Bluetooth simply select it from the list of paired devices.
      • To connect to OnStep via IP you must enter in the IP Address.

 

  • Sky Safari
    Sky Safari can connect to OnStep over Bluetooth or WiFi using the Settings>Telescope/Setup menu.
    • Scope Type: Meade LX-200 Classic.
    • Mount Type, etc. should match up with your build.
    • Set Time & Location: should always be disabled (causes long connection delays.)
    • If connecting via Bluetooth simply select that option and the device you paired with.
    • For WiFi you'll need the IP Address of your SWS and the port (192.168.0.1 and port 9999 are typically used.)
  • Stellarium Mobile Plus
    Stellarium Mobile Plus can control OnStep over WiFi.
    • Required WiFi, you'll need the IP Address of your SWS and the port (192.168.0.1 and port 9998 are typically used.)
    • Port 9998 (persistent IP) is required.

 
iOS (iPhone/iPad)

  • Website
    For setup, control, and status.
  • Sky Safari
    Sky Safari can connect to OnStep over or WiFi using the Settings>Telescope/Setup menu.
    • Scope Type: Meade LX-200 Classic.
    • Mount Type, etc. should match up with your build.
    • Set Time & Location: should always be disabled (causes long connection delays.)
    • For WiFi you'll need the IP Address of your SWS and the port (192.168.0.1 and port 9999 are typically used.)