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Last updated: 14 March 2005
| Last updated: 14 March 2005 |
Sent: Wednesday, March 9, 2005 13:17:21 From: Mark Ewert (zaphod@fmtcs.com) Meade produces a software package called Autostar Suite which includes a planetarium program along with telescope and dome control software. The telescope and dome control software allow the user to control the telescope and dome remotely over a network. To control the dome, the user manual states that the use must have a dome controller. I wanted to use the Autostar Suite to control my observatory and my telescope remotely so I contacted Meade to purchase the dome controller but was told that Meade is not going to produce the dome controller. Meade's web site at this URL: http://www.meade.com/autostar/as_suite.html continues to market this feature although it is not available. I thought that I could build a dome controller myself if I could get the software protocol. Meade has published its telescope control protocol so I thought that they would be willing to provide the details of the dome and `netscope' protocols. Meade declined stating that the protocols are proprietary. A simple network sniffer is all that is needed to examine the protocol and reveal the communication interface. Here is the information that Meade doesn't want you to know: ----------------- Telescope Control ----------------- Netscope.exe is the program that translates the network commands into serial port commands to the telescope and vice-versa. The protocol is very simple (thankfully). The protocol has two main phases which I call the Setup phase and the Normal phase. The Setup phase is first activated when netscope detects a new connection request. Netscope sends a password request and the remote user responds with a password. If the password is correct Netscope replies with "OK" and enters the Normal phase. If the password is not correct Netscope dissolves the connection and returns to listening for new connection requests. This is shown below. Remote PC Netscope COMM Telescope . < PSW? `pasword' > . < OK The Normal phase is made up of a routine handshake sequence and telescope protocol commands. The routine handshake sequence is initiated by the remote PC with the transmission of ":LK0#" followed by the transmission of ":LK1#". The proper response by netscope is "Yes#". Failure to properly respond to these handshake requests results in the Autostar Suite displaying a connection failure message. The Handshaking Sequence routinely occurs throughout the Normal phase. The protocol is shown below. Remote PC Netscope COMM Telescope :LK0# > :LK1# > . < Yes# The Normal phase is otherwise composed of telescope protocol commands and their responses. The telescope protocol is documented in the telescope protocols published by Meade. Here is a link to the latest protocol definition: http://www.meade.com/support/LX200CommandSet.pdf. The protocol includes the following command set commands: `.' ACK Used to determine the telescope axis alignment, ie. Polar or Alt-Az :U# Used to toggle between low and high precision coordinates. :GD# Used to get Declination Coordinates :GR# Used to get Right Ascension Coordinates :Srxx:xx:xx# Used to Set right ascension coordinates :Sdxx:xx:xx# Used to Set declination coordinates :Q# Used to Stop all motors :Qn# :Qs# :Qw# :Qe# :RS# Used to set the motor rate to Slew rate (Fastest). :RM# Used to set the motor rate to Find rate (Second Fastest). :RC# Used to set the motor rate to Centering rate (Second Slowest). :RG# Used to set the motor rate to Guide rate (Slowest). :FQ# Used to stop the focus motor :FF# Used to set focus motor rate to Fast. :FS# Used to set focus motor rate to Slow. :F+# Used to move focus motor in. :F-# Used to move focus motor out. The responses are as provided by the telescope over the serial line. Here is an example: Remote PC Netscope COMM Telescope :GD# > . :GD# > . < -26:34:00# . <-26:34:00# For all of the telescope commands, netscope acts as a relay agent taking the commands from the network and providing them to the serial port. Likewise the replies from the telescope are read from the serial port and are returned to the network. -------------------------------------- Potential Netscope Security Problem -------------------------------------- I've previously reported on the network and to Meade that Netscope has a potential security problem in that when the user tells netscope to open a port Netscope actually opens the port the user identified as well as the following 4 network ports. These additional ports are not mentioned in the user guides. When the user tells netscope to listen to the primary port, all five ports are opened in listening mode. If the user deselects the listen checkbox, only the primary port is closed and the other four ports are left open in listening mode. If a remote user tries to connect to these ports, the primary port is reopened for listening mode and functions as normal, however, the user's screen continues to show the port listen mode as disabled, although the status line is updated to indicate commands are being executed. A user might mistakenly think that they've taken their scope off the internet by deselecting the listen checkbox; however, the netscope design can still allow the remote user to move the scope. In my situation this can have disastrous effects as the scope could be driven into the ceiling of the roll-off roof when the roof is rolled on. ------------- Dome Control ------------- The Netscope.exe program has a window for identifying the COMM port to which the dome controller is connected. NETSCOPE makes no attempt to actually acquire this COMM port. The Dome control features appear to be a complete faade. The Autostar suite running on the Remote PC offer the operator a window with buttons marked Open Shutter, Close Shutter, Track to Scope, etc, however, the remote PC makes no attempt to actually make a network connection to the address and port the user provides. The program appears to be simply a graphical window which actually does nothing. Since Meade claims all of this functionality works in their advertisements on the web (See http://www.meade.com/autostar/as_suite.html) and my investigation seems to indicate that it can't possibly function, some people might conclude that Meade is guilty of lying or even false advertising. Others would call this `Creative Marketing'. It's no wonder Meade didn't want to divulge the Dome control protocol seeing that there isn't any! I've sent Meade an Email and a FAX describing the NETSCOPE port problem but they haven't returned my messages. I plan to produce Microsoft Visual Basic programs that replace the netscope.exe and the dome control programs in Autostar Suite with versions that actually work in the near future providing there is community interest. I also want to produce a netscope version that controls a Celestron CGE mount instead of only supporting the Meade Telescopes, but again, only if there is community interest. Thanks, Mark
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