As you are using 1x guiding rate, 100ms sounds way too much, if I calculate it correctly that would be 1.5 arc seconds, and the 0.5" you are after would be 33ms. So lower the minimum pulse value so that minimum correction is comfortably below pixel scale. Also possibly lower the guide rate to 0.5x, but that depends on the mount, my HEQ5 guides much more smoothly at 0.5x, but yours might like 1x better.

Can you explain how to convert a pulse length into a displacement in arc sec? Is this as simple as “1x guiding rate means guide at the same speed as at which stars move along the sky which is 15 arc sec per sec so a pulse of 100 ms equals 0.1 sec times 15 arc sec per sec equals 1.5 arc sec”?

Exactly, sometimes things are fortunately quite simple

Another thread recommended something like 20ms for minimum pulse width, which is what I am trying.

Testing last night after a good polar alignment with new OAG setup, seeing described as poor, using pulse guiding, and the guiding was awful, could hear the mount slewing around trying to track.

However once again starting guide calibration had caused "Invalid pier side response from device" errors from AstroPhysics Experimental driver which can be found in the kstars log. So cancelled guiding and took 60 second test image unguided which came out with nice round stars. If it remains clear will try again tonight using the ST4 cable instead of pulse guiding.

I have the same mount. With pulse it kicks the mount all over the sky during calibration. Jasem had me try ST4 (which I hate due to cord snag) but it eliminated the huge calibration jumps. (so that last that helps track down where the problem may be).

Recent. (last night) I was playing around somewhere and I saw a MACH1 indi driver I had never seen before? Is this new? outdated? as it didn't mention what GTO box was supported? I'm using experimental as well. But what of this mach1 mount driver?

I was using a OAG on my 6" APO - and pulse made for huge calibration (SLEWS) all across the sky. ST4 was better. But I need to figure out how to tweak controls... as I do in phd. I have min move down around 20 and Jasem said I should keep it at 100. (but I think the AP mount actually likes low min moves). I had it VERY LOW in PHD with excellent results.

The ST4 connection is usable. Nearly full moon, average seeing this evening according to the web site. The guiding calmed down though it goes off from time to time but was generally staying under 1.0 with a small refractor. The attached was with exposure extended to 8 seconds, Control Parameters: minimum guide pulse 20, Proportion reduced from 66 to 33. Probably not optimal but it improved over the defaults.

Not bad, AP says guide the mount at 1.0 rate. So you had that set to 1.0 and then under the target, you changed those settings to .20 min and the rate there was (it recommends 66) but you went 33? I'll try that again. I was set around there but Jasem said not to. However, 8 seconds seems excessive. Did you try 2-3 second exposure too?

I was trying to guide a big refractor with a .64 image sale. I'd need to be under that for a RMS error. You were at .79 I think it read... I just switched to a RASA with a 1/3rd shorter focal length which will reduce my image scale (I THINK it's .84) about now. Before going to INDI PHD2 averaged around .35 and often was as good as .24

I wonder if it's the server/client delay.... since trying external PHD on the PI server resulted in nearly the same as the internal guider. I'm not sure of where the correction is being calculated. (on the pi or on the client). But at 8 second exposure any server/client communications time would be irrelevant it would seem. I'm talking low ms I'd say.

changing to the RASA was done to lower FL, but also to reduce exposure times. Having a guiding glitch during a 10-20 minute exposure was frustrating to say the least. So from F8 and 3nm astrodon filters to F2.2 and high speed baader nb filters - I hope to shoot more but shorter exposures.

Yes I varied from 2 to 10 seconds, 25% to 66% etc without dramatic effect or finding a sweet spot. The incorrect/excessive 8 seconds 33% would track below 0.5 for a while and sometimes exceed 1.0. I did not learn much from the exercise on how the parameters work, but the way it tracks really well, then goes off for a while makes it seem like something external to the software needs attention. Think I will next try and run guiding without issuing any corrections, and see how the scope drifts to get a baseline.

Stay in touch here - since we have similar setup. Where are you? your profile pic weather looks like mine in W. Michigan = ) I'm about to head out and see if I can tweak shutter alignment now that it's off... since I switched scopes to a 11 rasa.

[b}SNAP! only took around 2.5 hours of tweaking to try and learn what teh settings do... but read em and weep![/b]

It's been in the .3's for the past 1/2 hour.

Thanks for sharing the screenshot. That ‘s very useful for next time I’m out there.


Wouter

If the 0.3 is repeated again on a different night using the same settings, then Ron is into something!!