Guiding control of the mount can be accomplished in 2 different ways. The guiding signals can be sent to the dedicated ST-4 port on the mount or they can be sent to the regular control port on the mount.

ST-4 Port and ST-4 Autoguider port rate

For the ST-4 port, the signal could come directly from the guide camera (if the camera supports that option) or the signal could come from a separate port on the computer using a relay or electronic switch box.

If user intends to use the ST4 based Autoguider port found at the faceplate of the mount's stepper controller, the “Autoguider Port Rate” sets the correction applied on the RA and DEC motors if any of the four ST4 lines (RA+ RA- DEC+ DEC-) are activated. Possible values are x1.0, x0.75, x0.50, x0.25 of the Sidereal rate.

ASCOM pulse guide settings

For guiding through the regular control port of the mount, the guiding signal uses the same cabling as the signals used for slewing and GOTO's.

Other than ST4 type of autoguiding, EQMOD also provides the “PulseGuide” Method where the correction commands are fed directly through ASCOM. A pulseguide message contains two parameters, the direction and the duration. The Pulseguide message currently does not contain any Guide Rate settings. The correction rate has to be provided by the user by means of two “slider bars” at the EQMOD setup window. Each bar specifies the speed of the RA and Dec motor during the course of the pulseguide correction. The Duration parameter (specified in terms of milliseconds) determines the duration to which the correction speed is applied. Once the duration of the correction expires, the RA speed is restored to the sidereal rate speed (or in DEC where the motor is stopped )

The pulseguide speed rate can be set between x0.1 to x0.9 of the sidereal rate at increments of 0.1 independently on each motor (RA or Dec).

The “Duration Override” option allows the user instead of the autoguiding application to dictate a fixed duration correction.

See further information about EQDIR and pulseguiding in the miscellaneous facts section.

Custom track rate

Other then the standard Lunar, Solar, and Sidereal rate, the user can specify the speed of each motor (RA or DEC) using the Custom Track rate facility. This option is provided at the Custom Track rate portion on the EQMOD driver setup window wherein the user will simply enter the rate in terms of arcseconds/second and then click on the [Execute] button. EQMOD will apply the rate on the two motors right after the [Execute] click. The Default value you see on the RA entry is actually the RA rate in sidereal. Clicking on the [Execute] button using the default RA rate value (15.04157) puts the mount in sidereal Tracking mode.

/home/welshdra/public_html/eqmod/data/pages/guiding.txt · Last modified: 2009/03/09 01:20 (external edit)
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