Re: To PEC or not to PEC..


Hi Rolando,

Your explanation is much better than mine.

The only drawback about spinning the spur gears with hand controller or third party software while mount is powered up is you may not be able to "feel" the tightness or looseness of the gears to see if the gears need remeshing unless you know a way. I have seen your instructions in your manuals about marking the spur gears with a pen so that you can return the spur gears to original location without affecting PEC if you rotate the spur gears by hand and the mount is powered off.


---In ap-gto@..., <chris1011@...> wrote :

Rotating the gears manually will lose the registration of the PE curve with respect to the gears. You can rotate them all you want with the drive buttons (on the keypad or other software/hardware). You just can't rotate the spur gears with the power off or when the mount is parked and the motors are not powered up.


-----Original Message-----
From: pnagy@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Fri, Dec 7, 2018 3:34 pm
Subject: [ap-gto] Re: To PEC or not to PEC..

Correct me if I'm wrong.

In addition to Rolando's excellent comments, I would suggest to never manually rotate the spur gears inside the gearbox cover because it will lose PEC unless you know exactly where to rotate the spur gears back to original spot. I think many people don't realize this.


---In ap-gto@..., <chris1011@...> wrote :

..that is the question (apologies to the Bard)

Hi Astronuts,

We have been shipping out 1100 mounts in the present production run, and as most of you know the mounts are tested here and loaded with a PE curve into the CP4 memory. Our mount technician, Dave, spends a considerable amount of time testing the native PE of the mount. He then creates a very accurate and smooth PE curve and loads that curve back into the mount. The resultant accuracy with PE turned on is 1 arc sec Peak to Peak or less (Rms typically comes in under 0.2 arc sec). I just saw on Crowdy Nights where one of our new customers ignored the loaded curve and created his own right off the bat, under very poor conditions to boot. The resultant PE looks worse than with PE turned off!

When we send out these mounts, a very accurate PE curve is in memory and can be turned on by the user. It is very accurate and does not need to be updated, even though we also send you a copy of PEMPro so you can create your own PE curve to replace the one already in memory. Don't be in a big hurry to create your own PE curve and load it into the CP4 memory. By all means play with the software, measure the PE with and without compensation turned on and even create your own curve and compare it to the one that's factory loaded into memory (PEMPro allows you to do that), but DON'T just overwrite what is there in memory to begin with. In fact it's a good idea to bring the factory curve up with PEMPro and save it on your laptop. That way you can always load it back into the CP4 if your own curve doesn't work out.

On top of that, if you are going to create a PE curve, make sure that you have a good night with good stability where the stars don't pulsate or move around due to upper atmosphere disturbances. Then also follow instructions so that your resultant curve is smooth, because if you load a ragged curve into memory, all those pops and sniggles will be played back faithfully and impact your tracking and guiding in negative ways.

You have been handed a fine violin that was tuned to perfection by Dave, our expert tuner. So practice that Mozart concerto with the instrument as is, before turning it into a slack key guitar.


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