The Minor Planet Observer
and
Palmer Divide Observatory

2007 Shoemaker Grant Recipient

MPO Connections - Scripting

The most powerful feature of MPO Connections is its ability to coordinate telescope and camera activity without you having to do a thing, save that you tell it to start doing so. The series of actions can be simple or complex, occur once or loop through a set of steps within the script until a given condition is met. In addition, the script can be told to wait until a specific event, e.g., end of twilight, an object reaches a minimum altitude, etc. Also, the script can check if a group of steps should be skipped if the initial command fails. For example, if the first step is to go to an object that is too low, there is no point in executing the step that would have taken an image of that object.

With power comes some complexity but MPO Connections is written to make the task of setting up a script as simple as possible. First, and foremost, you don’t have to know anything about programming in VB, Perl, Scripting Language, or any other language. All commands are selected from drop down lists. In addition, Connections provides automatic help when you select a command so that you can get it right the first time. Most important of all is that MPO Connections checks the script as the first step of running it. If it finds any errors, e.g., an invalid RA or Declination, you’re told about it immediately. There’s no walking away only to return to find the script came to screeching halt because of an invalid script entry.

About the Group Option

The Group value for each command is listed as either True or False. False means that the command is not usually included in a group and that it would probably be rare to do so. A value of True means that it is appropriate and often common to include the command in a group, usually one started with a GoTo command.

The actual value entered for the group must be an integer number of 0 or greater. A value of 0 is the equivalent of False, i.e., the command is not grouped with any others. A value greater than 0 (True) indicates the command is grouped with others of the same number.

The True or False listing is a recommendation and meant to guide you on the intended use of the command. You can, of course, group any set of commands that you want, keeping in mind that the "trigger" command is usually a GoTo command.

About GoTo Commands

Even if you have AutoSync set to True in the configuration settings, Connections does not AutoMatch after every slew when running a script. Use an occasional SyncLastPos to keep the scope’s aiming within tolerance.

Depending on the GoTo Coordinates setting in the configuration the RA/Declination values for all GoTo commands are either J2000 or the current epoch, even if the catalog positions are J2000. If current epoch is chosen, the J2000 position in the catalog is precessed to the current epoch. The exception to this rule is the GoToRADec command, which presumes the entered position to be in the designated epoch.

After selecting an item from the catalog - except asteroids, Connections inserts the RA and Declination values in the Arg1 and Arg2 fields. For asteroids, the position is computed "on-the-fly", allowing the script to keep up with those moving targets. For some extended objects, the catalog position may not be exactly where you want the image centered. You can override the position by inserting the desired values in the appropriate columns.

Alphabetical List of Script Commands