EQMOD with EQ5 Pro - Declination Backlash Handling

[morayskies]

Hi All

I have recently started using EQMOD to control my EQ5 Pro mount.  When I use the mount with the SynScan Hand Controller I have noticed the usual backlash in the Declination axis when reversing the direction from north to south or vice versa.  In the SynScan Setup/Backlash/Declination menu option, I find that setting this to 0deg 0' 50" (ie 50 arcseconds) compensates for the backlash when using the hand controller.  My questions are these;

1. When using EQMOD and the PC Direct mode setting on the hand controller, is this Declination Backlash compensation still applied? (I suspect not)
2. Does EQMOD have the functionality to apply similar Declination backlash compensation when using the the direction buttons in EQMOD to control the mount?

I intend using EQMOD's Pulse Guiding and see that there is a Declination backlash compensation for this feature.  Please bear with me whilst I ask another couple of questions;

1. I intend to use PHD2 as the guiding client.  I think that PHD2 will 'build in' backlash compensation when it performs its calibration.  If this assumption is correct, does this mean I do not need to enter any value into the Backlash compensation in the guiding area of EQMOD?
2. Out of curiosity more than anything else, what on Earth would the value be I should enter in the EQMOD backlash compensation? On the SynScan the backlash compensation is entered as an angular measurement (ie 50 arcsecnds) but in EQMOD guiding it seems to be entered as a time value (ie between 0 and 2000 milliseconds )

Anyway, thanks for looking.

[Dr_Ju_ju]

Hi Richard,

Firstly the best way to control your setup is to not use the handset at all... you'll need to get\use a USB to serial adaptor e.g. https://www.firstlightoptics.com/skywatcher-mounts/lynx-astro-ftdi-eqdir-usb-adapter-for-sky-watcher-eq5-pro-heq5-syntrek-pro-az-eq5-gt-az-eq6-gt-and-eq8-mounts.html

This then allows ASCOM (6.2)\ EQMOD \ PHD2 to drive the mount via CDC\Stellarium and guide using PHD2. If you spend the time to setup EQMOD correctly, then you will create a 'map' of the sky using known stars, which will then cater for any inconsistencies\backlash etc...

[morayskies]

Hi Julian

Thanks for this advice.  Must admit that, after posting, I did do a little more research and discovered that the EQ5 Pro can be controlled directly from a laptop using an EQDirect cable.  I had thought that this direct option was not available for this mount and using the PC Direct option on the handset was the only way to go.

I'm guessing from what you say that it is not really necessary to setup any Declination backlash compensation in EQMOD pulse guiding as PHD will cater for any backlash.  I was thinking more about using the direction controls in EQMOD independent of the pulse guiding.  The handset allows the user to enter a backlash compensation value which is applied when reversing direction (N to S to declination) but I don't think this is available in EQMOD unless, of course, I am missing something.

Cheers

Richard

 

[Dr_Ju_ju]

Hi Richard,

Yes, there will always be some backlash in the gearing of the mount, but EQMOD\PHD will take of that while guiding.

Within the EQMOD interface it is possible to drive the mount manually, N S E W buttons, as well as use a gamepad, but this usually for fine tuning while you build an alignment map, which will then cater for positional errors within the mount\software.