Yep that is a gear ratio that OnStep needs to know.

761/16 =47.56:1 reduction.

For the formulas in the excel sheet enter 1 for GR1 and 47.56 for GR2.

Steps per worm rotation is for GEMs and PEC.  So enter zero in config.h

On Sun, Apr 3, 2022 at 1:37 PM Gerry Byrne <byrnegerardf@...> wrote:

I cannot get Onstep to track properly and have encountered speeds more than twice expected tracking speeds. I wonder if you can suggest appropriate calculator and Config.h generator entries for my Dobsonian setup which I am sure I have miscalculated.

I have created an extra circular disc base for the right ascension drive to the entire circumference of which is glued a 6 mm belt (SEE PHOTO). This is connected to the drive of an ungeared  2 amp stepper motor with 1.8 degree steps and, I assume, a total of 200 steps. Each stepper motor is driven by an LV8729 driver (with 220 resistors for which I have set vRef of about 1.1 V, the max the potentiometer will generate).  The motor makes contact with the belt via a cogwheel with 16 teeth. There are 761 teeth on the belt. A similar setup drives the Dec side of things although only a segment of a similar radius wheel is employed. (See photos). The basic mechanics work very well in that the drives work without slipping and they hold firm when engaged. Although I have not experimented on it as much, I don't believe GOTO is very accurate either.

I think I getting confused over steps per wormrot (among other things): I don't have a worm, only a belt glued to the outside of a disc. Also, what does one put down for GR1 and GR2? There is no reduction gear on the motors and I wonder if a 761 tooth glued on belt driven by a 16 tooth pulley can be called a reduction gear.

Gerry Byrne

On 03/04/2022 15:02, Gerry Byrne via groups.io wrote:

Chris,

Solar tracking was selected and daylight saving was automatically rejected by Onstep. I did a timed one hour test this morning which suggests that the scope is tracking about 2.3 times faster than it should. I think I may have a problem with the parameters entered in config.h.

Gerry

On Sun 3 Apr 2022, 00:21 Chris Whitener, <chris.whitener@...> wrote:

Did you select solar tracking?
What about daylight savings time?

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Copernicus

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Copernicus