Meade ASCOM Telescope / Focuser Driver Information

The Meade ASCOM driver is an integrated driver with support for all of the Meade scopes  in one implementation.  This same implementation supports the Meade focuser protocol with an ASCOM focuser interface.   This Help file is still under construction, but is offered in in current form in order to provide some insights into the usage and behaviour.

• Telescope
  • First time procedures
  • Setup dialog
  • Model specifics
  • Parking
  • API notes
• Focuser
  • Setup dialog
  • API notes

Introduction

Telescope

First time procedures

This driver will take some information from the Mount the first time it is used.  In particular, the telescope needs to be in the preferred tracking mode (Equatorial or Alt / Az).  For this reason the driver requires that the mount be tracking the first time it is connected.  If this is not so, an error dialog will come up as a reminder.

After the fiirst time use, the telescope can be in any state at connect time.

Setup dialog

The Setup Dialog has a number key features.  The only required fields that should be examined are the Serial Port, and the 16" classic checkbox.  Some additional fields:

• Auto Set Time - If set, then the driver will set the Meade time to the computer time on connect.
• Auto Unpark / Track - If set, the driver will unpark and set tracking to true on connect (this is the old V1 behaviour, and is available for backwards compatibility)

Model specifics

Classic LX200

The Classic LX200 can have a park position remembered when used in the Northern hemisphere.  Defects in the Meade firmware prevent other cases from working at this time.

Autostar I

The Autostar I cannot be unparked.  This means that after a Park command is completed, that the software must be disconnected, and telescope power must be cycled before normal operation can continue.

Tracking state (on/off) cannot be controlled.  The scope is always tracking, unless it is parked.

LX200GPS

GuideRateDeclination and GuideRateRightAscension are tied together, and can be no larger than 15.0417 "/sec

Parking

For polar aligned scopes there is a default Park Position at 0 Hour Angle (on the Meridian), and 0 Declination.  For Alt / Az scopes, the default is at 0 Altitude, 180 degrees Azimuth (pointing due South).

The Park Position can be changed. Once it is set, it is remembered across sessions.  You don't have to set it again, unless you want to change to a new Park Position. If you don't overtly set the Park Position, the driver will assume your scope is at default wake up position (previous paragraph). If in fact you've woken the scope from a different position (say from manually moving the scope axis while off), then the scope will be lost, and manual sync to the sky will be required.

• To change the Park Position (default is 0 HA, 0 Dec):
  • make sure the scope coordinates are "right". In the day time you can position the scope to 0 HA, 0 Dec before turn on, or at night you can sync to any object in the sky.
  • position your scope at the desired Park Position.  Tracking state on / off does not matter.
  • use one of the various [Set Park] buttons in you application software or the Meade driver setup dialog.
• To Park:
  • press one of the [Park] buttons found in you software. You cannot simply move the scope to a position and turn it off. You must use a Park command. Then, do not move the scope until Unpark.
  • power down if desired.
• To Unpark:
  • power up the scope if needed. Do not move it.
  • connect with Software. If AutoTrack is enabled, you're done.
  • if no AutoTrack, then press Unpark.
  • you may need to turn on tracking as well.

Set park has a few quirks:

• It will be an error to set park position anywhere in the "wakeup" zone.  When the LX200 wakes up, it hunts for a worm start position.  We need to disambiguate simple disconnect / reconnect from true cold start.  The wake up zone is defined as about a degree from the 0, 0 point.  Set park is best used when the park position is a long way from the 0, 0 point.

API notes

• Unless listed below the Can flags will report True:
  • CanFindHome will return False
  • CanSetDeclinationRate will return False
  • CanSetGuideRates will be True for GPS scopes
  • CanSetPark will return True for Classic scopes in the Northern hemisphere
  • CanSetPierSide will return False
  • CanSetRightAscensionRate will return False
  • CanSetTracking will return True for Classic scopes
  • CanSyncAltAz will report False
  • CanUnpark will return False for the Autostar I scopes
• CommandBlind, CommandBool, CommandString support the optional "Raw" parameter.  If it is not found, or set to False, then these methods will add the Meade prefix (":") and postfix ("#") characters. CommandString will also strip the trailing "#" off the return string unless Raw is set.

Focuser

Setup dialog

(to be written)

API notes

• The Meade focuser is a "relative" focuser, and therefore the Position Property is not implemented.
• The StepSize Property is not implemented since the Meade focuser does not intrinsically know its step size.
• Temperature is unavailable
• Temperature compensation is not supported