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AP1600 Periodic Error

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#1 WadeH237



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Posted 25 February 2013 - 11:55 AM

I've had a couple of nights out now with my AP1600. I have to say that I love this mount!

I've been using CGEs for 10 years now. I've been really happy with the results, but there has been a learning curve. It took some time to figure out the best guiding settings, the best balance, etc. I knew that the AP would be a different experience in that it would "just work", but it's just now starting to sink in.

The AP works so well that, in my couple of nights out, I haven't bothered to do any PEMPro runs to measure its periodic error. I've brought the mount back indoors, as the weather has gone back to overcast. But it did occur to me that since AP programs PEC at the factory, I could just query the mount for its PE correction curve, and that this would give me a good idea of the raw PE.

I've seen that their mounts are usually under 5 seconds, but I was a bit suprised by the actual data on my mount.

Here is a screen shot of the PEMPro curve. I'm pretty happy about it.


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#2 lambermo


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Posted 25 February 2013 - 02:32 PM

Thanks for posting, I've added your PEC results to my list .

-- Hans

#3 frolinmod


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Posted 25 February 2013 - 03:35 PM

Was this measured with the factory programmed PEC already in place or with the PEC explictly and intentionally cleared so that there is no PEC of any sort programmed? It looks like it might have been measured with factory programmed PEC already in place.

If you program it yourself, you should be able to get it to go sub arc second.

#4 WadeH237



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Posted 25 February 2013 - 04:27 PM

To clarify, I did not do any measurements. I will get to it, but haven't made it a priority yet.

The curve you see here came from the PEC that was programmed into the mount at the factory by AP. In other words, this curve represents the corrections that the mount is programmed to make in order to offset PE. It should be pretty close the mount's raw, uncorrected PE.


#5 Ray Gralak

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Posted 25 February 2013 - 04:27 PM

I believe that is the factory PEC curve, which essentially shows the measured periodic error of the mount at the factory. When enabled periodic error should definitely be sub-arcsecond.


#6 orlyandico


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Posted 26 February 2013 - 12:17 AM

I have about 3.5" native on my Mach1, reduced to ~ 0.5" with the PEM enabled.

#7 WadeH237



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Posted 25 March 2013 - 12:00 PM

I just wanted to add that I've had a chance to actually measure the raw periodic error of the mount.

Here is the curve, per PEMPro. It's 1.63 arc seconds peak to peak (again, this is raw, with PEC off).


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#8 blueman


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Posted 25 March 2013 - 12:06 PM

That is excellent, but what would you expect from AP! :^)

#9 David Pavlich

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Posted 25 March 2013 - 12:56 PM

I'm a mount junkie and I'm here to tell you, that is good stuff!!


#10 Joe C

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Posted 25 March 2013 - 01:34 PM

Your PE Is WAY off and you need to ship me your mount to me right away and I promise to get it in line in no less than 18 months :-)

Congrats!! Looks great!

#11 jbalsam


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Posted 26 March 2013 - 01:23 PM

Looks about like my friend's AP1600 results. It's permanently mounted on a pier in his observing shed, so we've been dialing in the polar alignment with pempro on the two nights we've had so far. I was guiding the mount with PHD and watching the graph, and was shocked at how low the peak to peak movement was. And then I remembered that I was comparing it to my CGE... which cost one sixth as much.

#12 DeanS



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Posted 26 March 2013 - 02:41 PM

Here was my 1200 when I got it several years ago. I have never seen a need to use PEC since I guide anyways. :)

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#13 wz2


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Posted 26 March 2013 - 05:58 PM

Holy bajeebers - that's great!


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