Guiding a G11 mount

[Stefan12]

Hi,

I have a Losmandy G11 mount with Gemini 2.
Could someone please tell me how you go about guiding?
I'm using a Orion mini 50mm finder scope with an ST4 cable plugged into the guide port of the Gemini 2 control box. I have the guide rate set to 0.5 or 0.8.
Now, ever since I bought the mount I've never been able to get a consistent guiding result. I would have a nice flat guiding graph for a while, but then I would suddenly see a spike in either RA or DEC, which would be un guidable. The graph again would flat line.
I tried everything to stop it. Polar alignment, I checked for cable drag, I checked my power supply to see if there were voltage spikes, but nothing would stop it.
I then tried calibrating the guider as normal with a guide rate of 0.8x and then once calibration was complete, I then stopped the guider and changed the guide rate to 0.1x.
For some reason the guider worked! The guiding was flat and constant with no silly RA or DEC spikes.

So my question is what the heck is happening with my guider?
why does changing the guide rate after calibration dictate what happens to the guider?
I thought the guide rate should never have to be changed?

I'm using a WO Megrez 90mm

Stefan

[Shiraz (Ray)]

hi Stefan. the general idea behind guiding is not to aim for a flat guide graph - rather you should aim for round stars. The guide graph will show you the errors in the mount that are being corrected by the guider - if that is flat, then the guider is not doing anything. If your settings are such that errors persist and build up to the point that a major correction must be made, then you will get occasional spikes.

What software and settings do you use? From what I have read, I think that you will get best results using a guide update of about 1 second with the G11. That will give you a guide graph the jitters around due to seeing fluctuations and mount errors, but the stars will be good. I don't know what the best mount correction rate is, but around 0.5 would probably be a good starting point.

[Stefan12]

Hi Ray,

I've been using PHD to guide, but I have now switched to Maxim DL to guide.
I had some clear sky for a while tonight, so I tried changing the guide rate from 0.8 to 0.1 after calibration. I then took a 20minute exposure through my ha filter. The results were perfect round stars.
I'm new to maximDL and don't know if you're familiar to guiding using maxim, but only settings I've played around with a cal time of 20 and backlash set to 8.

Stefan

[Manav (Yugant)]

Hi Stefan - I wouldn't change the default settings for MaximDL it usually works pretty well. The tutorial attached herein may help.

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