PHD settings for finder/guider?

[michaelmorris]

On the last night at Kelling Heath I experimented using Finder/guider mounted on my HEQ3 Pro mount.  The guide camera is a Lodestar.

I could only get PHD to calibrate using exposures of 4.5 seconds and winding the calibration steps up to the maximum 9999m/s. (see screen shot below)

Is there an easier way to get it to calibrate?

Thanks

[Freddie]

What guide rate do you have set on the mount? Something is not right somewhere. Exposure time will only impact on your ability to pick up a guide star.

[michaelmorris]

What guide rate do you have set on the mount? Something is not right somewhere. Exposure time will only impact on your ability to pick up a guide star.

The guide rate is sidereal.

I too was surprised when the exposure length made a difference to the amount the scope moved.

[Freddie]

You should find that that's the tracking rate and there will also be a guiding rate in there somewhere.

[glowingturnip]

personally I'd upgrade to PHD2 - works well for me, though I know others don't like it...

[Scott]

I'm with Stuart. I use phd2 and it seems to have less issues than when I used phd1. that said, I've also heard of some folk who have all sorts of probs with 2. may be worth a try though

[Xiga]

i tried guiding last night for the first time (also using a Finder Guider). I was doing ASCOM pulse guiding instead of using the ST-4 port.

I also had real difficulty getting it to calibrate. Three times it got to 40 steps and i had to abort.

In the end what did it for me (and just as Freddie said above) was to change the default RA & Dec Rates in the PulseGuide Settings. By default they are at 0.1, and the star was barely moving for me. So i upped them to 0.5 each and hey presto, it then calibrated in 12 steps.

http://eq-mod.sourceforge.net/docs/EQASCOM_Guiding.pdf

Hope that helps.

Ciarán.

[michaelmorris]

i tried guiding last night for the first time (also using a Finder Guider). I was doing ASCOM pulse guiding instead of using the ST-4 port.

I also had real difficulty getting it to calibrate. Three times it got to 40 steps and i had to abort.

In the end what did it for me (and just as Freddie said above) was to change the default RA & Dec Rates in the PulseGuide Settings. By default they are at 0.1, and the star was barely moving for me. So i upped them to 0.5 each and hey presto, it then calibrated in 12 steps.

http://eq-mod.sourceforge.net/docs/EQASCOM_Guiding.pdf

Hope that helps.

Ciarán.

Thanks.  That sounds like a fix.

[Xiga]

Once you make this change, you will also need to revise your PHD settings. 

Up the max RA & Dec durations to 2000ms (remembr, these are only max, so it doesn't do any harm to up them, especially the Dec if your PA isn't great)

Bring the calibration steps way down, try 2000

Reduce RA aggresiveness a bit to 70

Reduce the min motion. This one depends on the ratio of your imaging & guiding setups so you'll need to work this one out yourself. For example, the resolution of my imaging scope is 1.74 arc secs per pixel, but my imaging scope is 5.36 arc secs per pixel. So i image at roughly 3 times the resolution that i guide. 1 arc sec on my guide scope = 1/5.36 = 0.18 pixels, which equates to roughly 0.06 pixels on my imaging scope, so i set mine to 0.05. This setting usually works well for those using Finder Guiders.

Remove the noise reduction. Unless you have a very low spec guiding camera you shouldn't need this. I suspect you only changed it as a last resort?

A good idea is to also install PHD2 (even if you don't intend on using it). Once installed, it will run through a setup procedure and set your settings to whatever it thinks is best. The only piece of info you'll need to know yourself is the focal length of your guide scope, i think mine is around 200mm. For me PHD2 came up with practically the right ones, the only thing i had to do was reduce the Min Motion setting, as it presumes your guiding rig and imaging rig are at a 1:1 ratio (like if you were using an OAG). It came up with 0.18 for me, so i just changed it down to 0.05. 

[tony210]

Hi -I think 4.5 seconds is generous for your mount - I always used 2.5 for a well polar aligned EQ6-also if well polar aligned lower aggressiveness and max duration are beneficial but tricky as does depend on seeing as the start profile is adversely affected by poor seeing - best wishes Tony