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Article Number: SBKB-10-10003

Meade Autostar Ignores Tenths of an Arc Minute in Right Ascension


Information in this article applies to:
  • TheSky Astronomy Software version 5.00.000 and later

When communicating with the Autostar version 1.3 via its built-in serial port, the Autostar ignores tenths of minutes for the set object right ascension ":Sr HH:MM.T#" command.

To duplicate this behavior, run HyperTerminal (9600, 8, None, 1, No Flow Control) and send the ":Sr HH:MM.T#" command immediately followed by the get object right ascension command ":Gr#" to retrieve the value just set. The retrieved value will not match the set value if right ascension's tenth of a minute is non zero.

Here is sample HyperTerminal output:

:Sr 20:12.2#1


The set object right ascension command is how the Autostar is instructed to slew and sync on an object. The coordinates of the Autostar will not match the coordinates that were sent to it if tenths of a minute right ascension are required. 


This is a limitation with the Autostar version 1.3 and can result in fifteen arc-minutes of inaccuracy when this device is controlled via the serial port.





More Information

Contact the telescope's manufacturer to determine if an updated version of the firmware is available.

Modified: July 26, 2004