Triple Piggy Back Works!


Peter Bresler
 
Edited

Triple piggy back works! Shot taken with the SV80, weights are nearly maxed out.


Frank Widmann
 

AP has an extension for the counterweight shaft.

Frank

On Dec 23, 2020, at 5:12 PM, Peter Bresler via groups.io <PABresler@...> wrote:



[Edited Message Follows]

Triple piggy back works! Shot taken with the SV80, weights are nearly maxed out.
<20201223_140214.jpg>
<IC 1805 Heart Nebula HHSO.jpg>


Frank Widmann
 

I’m not impressed with the image, particularly with an 80 mm scope. AP cautions against large moments of inertia. You are moving the center of gravity a long way from the RA axis. Even with good balance that creates a high inertia load. You have created a real cable management nightmare. All those wires add weight, affect balance and are snag opportunities. 

Frank

On Dec 23, 2020, at 5:12 PM, Peter Bresler via groups.io <PABresler@...> wrote:



[Edited Message Follows]

Triple piggy back works! Shot taken with the SV80, weights are nearly maxed out.
<20201223_140214.jpg>
<IC 1805 Heart Nebula HHSO.jpg>


Jeffrey Wolff
 

Which mount do you have loaded up. I currently have the AP900 but waiting on the AP1100 so I can piggyback a refractor on my 10 inch f/4 newtonian. 

Your wires look like they have a lot of potential to snag. Looks like you have a roll away shed. I also use one.

Jeff


Robert Sinitiere
 

Well now you’ve done it, now I will have to place a quadruple piggyback on my AP SCOPE! Just kidding, your imaging set-up is magnificent and so are your images!

🎄🎄🎄⛄️Merry Christmas and Happy holidays!⛄️🧐🔭🎼🎄⛄️.  Bob S in Baton Rouge.    Stay safe!


On Dec 23, 2020, at 7:12 PM, Peter Bresler via groups.io <PABresler@...> wrote:



[Edited Message Follows]

Triple piggy back works! Shot taken with the SV80, weights are nearly maxed out.
<20201223_140214.jpg>
<IC 1805 Heart Nebula HHSO.jpg>


Peter Bresler
 
Edited

In spite of the inertia the guiding with the OAG appeared to be good. The mount is balanced as is. I cannot add an extension bar because the shed doors would not close. There are some processing issues with that image that I still am working on. I have been working on organizing the wires and lengthening them. Cable snags are infrequent now. I probably will remove the small scope when not in use. It still is easier than switching them around. The mount is a 1200.


Roland Christen
 

To make something like this work, be sure to balance both axes very accurately. Once in balance, the torque required by the drive motors is no higher than a completely un-loaded mount. What happens when you have some imbalance, especially in the Dec axis, is that the pressure on the worm teeth increases dramatically. This causes high friction that impedes precise motion of the Dec axis at sub-arc sec levels. You may get increased delay when the axis is commanded to reverse during guiding and possible overshoot if the friction is really high.

With good balance the encoders will command the Dec axis to move almost instantly for same or reversing directions. With out of balance, the encoders will try to compensate but if the friction is too high you will get jerky motions at sub-arc sec levels.

Rolando



-----Original Message-----
From: Peter Bresler via groups.io <PABresler@...>
To: main@ap-gto.groups.io
Sent: Thu, Dec 24, 2020 11:01 am
Subject: Re: [ap-gto] Triple Piggy Back Works!

[Edited Message Follows]
In spite of the inertia the guiding with the OAG appeared to be good. The mount is balanced as is. I cannot add an extension bar because the shed doors would not close. There are some processing issues with that image that I still am working on. I have been working on organizing the wires and lengthening them. Cable snags are infrequent now. I probably will remove the small scope when not in use. It still is easier than switching them around. The mount is a 1200.

--
Roland Christen
Astro-Physics


Jeff B
 

A +1 what Roland said about balance in all directions/axes.  In the 11" F7.2 Newtonian on the 1200, I have 85 pounds worth of weights.  I very carefully balanced the tube in RA but also paid particular attention to the DEC.  You can't see it because it's on the other side, out of view, but I added an aft ring with a weight counterpoise to the focuser/bino-viewer/finder assembly to counteract their combined off axis torque.   Works well.  I also decrease the slew speeds to 600x (if I could, I'd probably go down to 500X or maybe even 400x).

Jeff

On Thu, Dec 24, 2020 at 12:44 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
To make something like this work, be sure to balance both axes very accurately. Once in balance, the torque required by the drive motors is no higher than a completely un-loaded mount. What happens when you have some imbalance, especially in the Dec axis, is that the pressure on the worm teeth increases dramatically. This causes high friction that impedes precise motion of the Dec axis at sub-arc sec levels. You may get increased delay when the axis is commanded to reverse during guiding and possible overshoot if the friction is really high.

With good balance the encoders will command the Dec axis to move almost instantly for same or reversing directions. With out of balance, the encoders will try to compensate but if the friction is too high you will get jerky motions at sub-arc sec levels.

Rolando



-----Original Message-----
From: Peter Bresler via groups.io <PABresler=aol.com@groups.io>
To: main@ap-gto.groups.io
Sent: Thu, Dec 24, 2020 11:01 am
Subject: Re: [ap-gto] Triple Piggy Back Works!

[Edited Message Follows]
In spite of the inertia the guiding with the OAG appeared to be good. The mount is balanced as is. I cannot add an extension bar because the shed doors would not close. There are some processing issues with that image that I still am working on. I have been working on organizing the wires and lengthening them. Cable snags are infrequent now. I probably will remove the small scope when not in use. It still is easier than switching them around. The mount is a 1200.

--
Roland Christen
Astro-Physics


Peter Bresler
 

I am very careful about checking balance and recheck it when I change cameras. I think it is right on. I also remove the somewhat heavy scope front cover from the Planewave even if it is not the scope in use.