Strange Eqmod issue

[jnc71106]

Ok here's a weird one I can't work out hopefully someone might be able to help

Setup my HEQ5 today and when slewing to a target in CDC using Eqmod there was an unholy noise coming from the motors which was not normal I know what a normal mount sounds like. However when I slewed in RA or DEC only with the eqmod directional controls there was no grinding noise at all

The only way I could get it to stop was by reducing the max goto rate down to 100 but obviously this means goto's take an age to complete

I thought it was maybe the worm gears being to tight....but just before I made any adjustments to them I plugged in the synscan handset and told it to slew to a target and it did this without making any noise at all

So I'm wondering why I have the issue with Eqmod but not the synscan handset

Anyone ????

[chrisshillito]

Was the goto rate set to 'none' or were you already limiting the goto rate at the time? Some rates are inherently very noisy - its due to the stepper motor harmonics and the resonance with the other moving parts, no harm is done though but it does sound dreadful.

Chris.

[jnc71106]

The goto rate was on 400 but even on 200 it was awful it's now on 100 but I can still hear it doesn't sound right I'm just curious as to why it does this when it's doing a goto slew with eqmod but not if i move just the RA or dec

The same with the synscan handset no noise at all on a goto slew it sounds exactly like it should

I've owned 2 heq5's and an eq6 and never had this before

[chrisshillito]

Like I said some movement rates are noiser than others. Set the goto limit to 'none' and EQMOD will behave exactly like the synscan and let the mount itself determine what rate to use for gotos.

When you do a manual slew the rate is determined by the slew rate slider or currently selected slew preset. Set this rate to 400xSidereal and you should find you get noisy manual slews as well.

The synscan only permits movement at one of its 9 set rates and for gotos/parks the mount chooses the rate. Clearly they've arranged things in their firmware to avoid those rates that generate the most noise. With EQMOD we've given you the flexibility to select any rate you wish and for things like satellite tracking this is essential, but this does mean the noisey rates are not filtered out and is really up to you to work out which values to avoid.

Chris.

[chrisshillito]

Oh I should have said that if 400 is noisy try another rate that isn't a factor of 400.

[jnc71106]

Cheers chris I will have another play around tomorrow see how I get on will post my findings

[jnc71106]

all sorted now. changed the goto rate to "no limit" and its lovely and quiet now

thanks for your help chris