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PHD Calibration

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#1 CharlesW

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Posted 17 February 2013 - 12:29 AM

I am new to the hobby and have been slowly learning how to integrate my hardware and software. Tonight I got PHD guiding for the first time on M42. It took about 12 minutes for PHD to go through the EWNS calibration before guiding. Then I took a sample image and had to reframe a little bit. That broke the guiding and I had to restart the EWNS for another 12 minutes. Does this happen everytime you need to reframe a shot or guide on a new star? Is there a way to make that process go any faster?

#2 fmhill

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Posted 17 February 2013 - 12:45 AM

You do not have to recalibrate the EWNS when you reframe, simply go back and recapture the guide star and then start the guiding again...

As to taking 12 minutes to do the EWNS calibration, if its taking 12 minutes instead of 2 to 4 minutes or less, you may need to change the calibration step size. This can also be affected by other settings in PHD, if you post the PHD parameters or screen shots of both the PHD guiding graph and the "Brain" settings page along with your guide scope and OTA information, then I can advise you as to adjusting settings in PHD...

#3 zerro1

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Posted 17 February 2013 - 01:17 AM

I'm using an older release of PHD, but once my system completes the calibration successfully, I would have to go into advanced settings and tick the checkbox "force calibration" before PHD would try to calibrate again.

did you completely shut PHD down?
What Guide Camera and guide scope are you using?
What Mount?

#4 CharlesW

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Posted 17 February 2013 - 01:42 AM

I'm using the Orion Starshoot camera through an Astro Tech 65mm scope. It guides a Celestron CPC800, 8" SCT fork mount. Attached is a shot of the Brain screen. I shut the scope down a couple hours ago so I don't have a shot of the graph. Thanks

Attached Files



#5 DaddyBear123

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Posted 17 February 2013 - 01:48 AM

Drop your calibration step to anywhere between 500 750 should help

#6 fmhill

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Posted 17 February 2013 - 02:19 AM

I do not see much different in your settings than what I use with a Celestron 80mm f7.5 guide scope and an Orion SSAG...

The only two parameters in the "Brain" area I would change are the calibration step, I would try settings in the range of 750 to 1500. The second is the Max Dec Duration, "rule of thumb" should be the same or larger than the Max RA Duration. However I do not think any of this is why you are getting long calibration times. Its more likely to be the quality and brightness of the calibration star and the exposure time, brighter is better and shorter exposure times give the best guiding in my experience.

I'd try a different guide star...






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