Re: #Keypad Park Positions: AP 1100 GTO with encoders #Keypad

Thomas Giannaccini

Thank you for the time you took to write that email. Yesterday, I was able to follow your instructions with some success but an issue still remains. I will outline my actions below.

I rough polar aligned the mount using RAPAs.
I updated the keypad firmware. I still do not have Park 5 in my list. Therefore, I used Park 4 instead, as will be described. 

I double checked my time and location data. Please note I am currently in the mountain time zone. The time was precisely synched at the correct moment although the screen shot of the official time was taken a few seconds after the time synch was completed.


I began this process with Auto Connect "No" to see how the process would go and to allow for a comparison.

I started in Park 3 (a rough, eyeball approximation)
I slewed to Park 2; It was spot on. Level was verified with a carpenter's level, 
I slewed to Park 4. It was off as shown below. The RA moved correctly The CW shaft was level and pointing West. When the Dec axis rotated it stopped at approximately the 10:30 position (just past 10 O'clock) and retreated to about 10 O'clock. This makes me think some sort of limit was hit?
I then adjusted the OTA position so that it was correctly in Park 4. this change in Dec axis rotation was made my loosening clutches and moving the OTA by hand. Level was verified with a carpenter's level. 

I then slewed the mount back to Park 3. It was also not correct. It appeared to be off by the same amount that Park 4 was off. This is what Park 3 looked like:

Again I loosened the clutches, corrected the OTA position to Park 3. Then I slewed to Park 2. It was, again, spot on. Park 4 was again off by the same amount as before.  So the issue here is that I can attain either Park 3 or Park 4 but not both. This was all with AutoConnect "No".

I then selected Auto Connect "Yes"
I powered down the mount. I plut the OTA in Park 3 by loosening the clutches. I powered up the mount and repeated the above process Going from Park 3 to Park 2 to Park 4.  The behavior of the mount was identical to when AutoConnect was set to "No"

I then went to the polar alignment menu. Used 3 star alignment with a Reticle eyepiece in the main OTA. I slewed to 3 target stars. Polaris, Vega, and I can't remember the third. Each time any necessary adjustments were made only using keypad direction keys. I synched each star. No re-cal was performed. Just synch to each of those 3 stars. 

Then I slewed to targets. I would describe the mount performance as nearly flawless at this point; certainly good enough for where I am in my learning curve. 

If starting in Park 3, verifying Park 2 and then polar aligning via 3 stars will yield accurate results, this is easily within my grasp. I will continue to leave Auto Connect On and just restart from where I left off. I agree that this will be much easier. Thank you for the suggestion. I did not understand the details as you described them regarding a permanent mount.

Lastly, I placed a volt meter in line from the battery as you suggested. It is now semi-permanent. I did notice that the voltage dropped pretty quickly from over 13 volts to somewhere between 12.5 to 12.85 volts but was always above 12 volts.

Thank you for your help,


On Wed, Sep 22, 2021 at 12:05 PM Roland Christen via <> wrote:
You have basically a permanent setup and I believe you are missing a fundamental fact about the mount CP4 controller. The fact is that the controller always knows where the mount is pointed, even after the power is removed. That assumes that you do not take the telescope off the mount and disturb the positions of the axes by loosening the clutches. Therefore, once you have established the mount's position in the sky by having it go to a known object and doing a Recal on it, then all other positions will be correct. There is never a need to go to a known park position and doing a "Resume from Park X" routine.

The absolute simplest and most foolproof way to operate your mount is to change the setting in the keypad from Autoconnect "NO" to Autoconnect "YES". This will insure that the logic in the mount servo controller is always in charge of the operation and is never fooled by human error during startup. With Autoconnect YES the mount will start automatically and will never be lost or go to wrong park positions. You can move your mount on the dolly and it will not change the mount's internal calibration - as long as you never loosen the clutches and move the axes manually.

You have a permanent setup, which is defined as having the telescope attached to the mount and never removed and not disturbing the axes by loosening the clutches. Therefore the best, easiest and most sure-fire way to start your mount is to allow the mount's controller to determine where the axes are, and not over-riding this internal knowledge by starting manually every time. Set the keypad to Autostart YES and your startup will be seamless and accurate every time. Of course you can park your mount at any of the park positions at the end of your session, even Park 1 if that's where the setup clears your roof. Autostart YES will take all that into consideration, EVEN if the mount is parked with counterweight up and past the meridian!!

IMPORTANT: as long as you never loosen the clutches and move the axes manually.

We put a lot of smarts into the CP4 controllers in order to make operation of the mount as simple as possible. You take advantage of that by setting the keypad to Autostart "YES". If you always start with Autostart "NO", then you are throwing away all the smarts that are built into the mount, and it becomes just another mediocre mount that needs a lot of babysitting to get it going every night. Does all this make sense to you?

Roland Christen
Astro-Physics Inc.

-----Original Message-----
From: Thomas Giannaccini <tgiann3@...>
Sent: Wed, Sep 22, 2021 11:42 am
Subject: Re: [ap-gto] #Keypad Park Positions: AP 1100 GTO with encoders

The mount and pier are on a motorized dolly. The dolly moves about 20-30 ft. I have not taken the setup apart yet but in the future, yes, it will be disassembled and substantially moved. 

I think updating the keypad to Park 5 and using the sequence you suggested will go a long way. 

Thank you,


On Wed, Sep 22, 2021 at 8:42 AM Roland Christen via <> wrote:
Let me ask you a more fundamental question. Do you have a fixed setup where you do not remove the scope from the mount after each session?


-----Original Message-----
From: Thomas Giannaccini <tgiann3@...>
Sent: Tue, Sep 21, 2021 9:32 pm
Subject: Re: [ap-gto] #Keypad Park Positions: AP 1100 GTO with encoders

I received an email from Roland telling me to use Park 3, 2 and 5. So I will try that. 

I think I generally only used “resume from park” on the initial startup. Initially that was Park 1, until George said to use Park 3. So, from that point forward I would resume from Park 3. 

I store the mount in Park 1 so it will fit in the shed. Perhaps I can try Park 4 or 5 to store it. I will first try resuming from Park 4 or 5 but if that doesn't work, I will just start from Park 3 by manually placing it there by hand if necessary  after slewing to Park 3.

In terms of waiting, I never timed it but I never went immediately to a target, I didn’t realize there was a time crunch. I did read the manual but I think it takes a few iterations for it to all sink in. 

What was confusing is that some Park attempts would end with the OTA in very odd positions. So it wasn’t a small margin of error as if the difference was based on movement from tracking; there were many times it wasn’t even in the ballpark. As to if the weights were pointed upwards, I did not notice them pointing up but if it was by a small amount I may not have seen it.

I am interested to try Roland’s suggestion. I think I may have to update my keypad to get Park 5. 

I try not to bog the forum with beginner questions, I only really ask when my attempted solutions don’t seem to work at all.

Thank you for your help,


On Tue, Sep 21, 2021 at 6:56 PM Mike Dodd <mike@...> wrote:
On 9/21/2021 8:37 PM, Thomas Giannaccini wrote:
> When I try to attain Park 4 by slewing to it then
> manually adjusting, it throws the other Park positions off.

After you manually adjust the mount in Park 4, what do you do next? Do
you "Resume From Last Parked?"

> ...when the mount is in Park 1 and slews to Park 4 which way
> is the main objective of the OTA supposed to swing? South or North?

In Park 1, the OTA is horizontal pointing north. In Park 4, the OTA is
horizontal pointing south.

The issue with Park 1, as pointed out by A-P, is that as soon as you
unpark, the mount is tracking, and after only a few seconds, it believes
the counterweight is up, which can be bad. From the keypad manual: "Park
1 is only seconds away from tracking into a counterweight-up status and
slews from Park 1 to western objects may cause the scope to point toward
the ground when beginning the slew."

How long do you wait after unparking from Park 1 before you slew to a
sky target? I usually do that immediately, as quickly as I can pick a
target. I have never had a problem unparking from Park 1 if I'm quick to
slew  to an east target. But, again, Park 4 where I level the mount and
OTA if necessary. (Actually, I will use Park 5 in the future because
that doesn't stretch my imaging cables as much as Park 4.)

--- Mike

--- Mike

CN: HasAnyoneSeenMyNeblua

Roland Christen

CN: HasAnyoneSeenMyNeblua

Roland Christen

CN: HasAnyoneSeenMyNeblua

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