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CPC800 autoguide rate

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#1 CharlesW

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Posted 23 February 2013 - 10:15 AM

For those of you that have a similar set up I'd appreciate some information. I have the Orion Starshoot Autoguider plugged into an Astro Tech 65mm refractor that rides on top of my CPC800. The guiding is controlled by PHD. I'm looking for the mount autoguide rate that you've found works and also the calibration step size in PHD's brain panel. I don't want to appear to be rude, but I don't care about theory right now. I just want the $1000 brick sitting on top of my OTA to finish calibrating in less time than it takes me to make dinner. I have had it successfully guiding twice, but that's only after using outlandish step settings.
I should add: I'm on a wedge, polar aligned but not drift yet, tracking is EQ north and sidereal.
Thanks in advance.

#2 Peter in Reno

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Posted 23 February 2013 - 12:00 PM

I used to have CPC0800. I used default guide rate. I don't remember the default guide rate. If your issue that PHD calibration takes too long, then the calibration step size is too short. Increase the step size until total number of calibration steps is about between 8 and 20. Start by doubling your current step size and if the calibration still takes too long, keep doubling the value.

Peter

#3 Peter in Reno

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Posted 23 February 2013 - 12:33 PM

Also make sure you are not trying to guide on a hot pixel. Hot pixels can be mistaken for real stars.

Another possibility is if you are trying to image an object near the pole, then calibration can take a long time. You can calibrate on a star further away from the pole and then slew to target object and start guiding. The further away the star is from the pole the shorter the calibration.

Peter

#4 CharlesW

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Posted 23 February 2013 - 01:17 PM

Definitely not a hot pixel, I was using a star in the east, and I was over 6000 before I got a calibration step to work. 6000 seems really high since most everyone else appears to be around 1500.

#5 Peter in Reno

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Posted 23 February 2013 - 02:13 PM

6000msec is pretty high. PHD default settings are usually for short focal length scopes like yours. I don't know why you are having issues.

Peter

#6 parkj

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Posted 26 February 2013 - 06:46 PM

You did not tell what is your guide rate. try 99% for both RA/DEC - can change from the hand set. I normally use - 600mm FL guide scope - 50 ~ 99 % with PHD calibration step ~ 1000ms. Even with 50mm finder scope as guide scope, 90% and 1500ms calibration step works fine.
Both RA/DEC calibration take same lone steps ? If there is DEC stiction problem, DEC calibration can take long-long time, of course result in bad calibration.

JC






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