Re: Meridian Flip Feature Yet?

Ray Gralak

Hi Ray,

Ray Palmer says - Why do we even need to trick the mount at all, when so many other mount manufacturers offer
a simple pier flip command as stock standard functionality?
Let's use your "other manufacturer" pier flip button as an example:

1. Say the mount is at (RA_1, Dec_1) - whatever coordinates those happen to be.
2. You click the "Pier Flip" and the mount goes to (RA_1, Dec_1) on the other pier side.
3. Later, you want to slew to (RA_2, Dec_2), but on the other side of the pier.
4. You first click the "pier flip" button, and the mount slews to (RA_1, Dec_1) on the opposite side of the pier, but you are not done.
5. Now you still have to issue the slew to (RA_2, Dec_2).

Is that how the other manufacturer's pier flip works? Is that how you would like it to work?

Now for an AP mount, using the meridian delay will define the destination pier-side of a slew such that there would only be a single slew from (RA_1, Dec_1) to (RA_2, Dec_2) on the other side of the pier.

-Ray Gralak
Author of PEMPro
Author of APCC (Astro-Physics Command Center):
Author of Astro-Physics V2 ASCOM Driver:

-----Original Message-----
From: [] On Behalf Of ray.palmer@...
Sent: Monday, December 28, 2020 7:09 PM
Subject: Re: [ap-gto] Meridian Flip Feature Yet?

Ray Palmer says - Ray Gralak and Rolando, I appreciate all your feedback so far, but it has become evident that
many AP owners do NOT have access to a simple pier flip feature like so many manufacturers offer as a stock
standard feature with their mounts.

Ray Gralak says - First, as Roland pointed out, there is a way to do the pier flip from the hand controller.

Ray (Palmer) says - that's great news then. I'm using a 1600GTO with a GTOCP3 using the latest software
4.19.3. How do I do a simple pier flip please? What is the keypad path? I tried using +- and pressing 9, as per
Rolando's instructions, but it doesn't do anything.

Ray Gralak says

I don't know, as I hardly use the keypad.

Ray Palmer says - I do not really use the keypad either my friend. But Rolando has now indicated that my setup
using the GTOCP3 cannot perform the keypad pier flip.

Roland Christen says - Your CP3 does not have the software commands for flips and a lot of other new

Ray Palmer says - So it is evident that there is NO simple dedicated pier flip command for many AstroPhysics
mount owners. That has now been clearly established. Only playing with the meridian delay or performing other
measures such as writing a script can I do what many other mount manufacturers offer seamlessly. This is a
gaping hole in AP's firmware and software that desperately needs to be plugged.

Ray Gralak Says - BTW, APCC has a meridian limits explorer tool to map out the slew limits at every declination
and pier side. Once mapped out, APCC automatically allows pier flips within the meridian limits. Note that the
concept of "meridian limits" is not the same as the mount's "meridian delay".

Ray Palmer says - Yes, I have seen that feature and I appreciate you are trying to assist me, I really do, but I've
said so many times in this thread, my reason for needing to pier flip has nothing to do with the meridian's position.
So the meridian explorer tool to map out slew limits does absolutely nothing for me. I keep saying in this thread
that pier flipping is required for so many other reasons than just the meridian's position. Because AP mounts can
track so far across the meridian everyone seems to be think there is no possible other requirement for pier flipping.
The meridian is only 10 percent of the reasons why people need to pier flip. If anyone thinks that pier flipping is
only for the meridian, then I would invite them to visit my observatory and see what an astronomer does over a few

The idea that pier flipping is meridian based is strongly misguided.

Ray Gralak says - A pier flip in any mount results in multiple operations. In the case of an AP mount, the meridian
delay is just one of the two commands needed to do a pier flip:

1. Set meridian delay.
2. Slew to current RA/Dec.

Setting the meridian delay sets the destination pier side.

Ray Palmer says - Why do we even need to trick the mount at all, when so many other mount manufacturers offer
a simple pier flip command as stock standard functionality? AP owners shouldn't even have to think about
meridian delays, what side of the mount are we tricking etc, it should just be a single pier flip button and she flips
instantly, should not even have to make another Goto command. This is what most, if not all other manufacturers
offer, why can't AP?

What does "Pier side" mean please?

Ray Gralak says - APCC has a button to do a pier flip, but a simple script can be made to perform the pier flip
without APCC. The script could be placed on the desktop and double-clicked when needed. I can't help you with
the AP keypad operations, but I can create a (free) script for you that will flip the mount if you are interested?

Ray Palmer says - I would be interested in this script my friend and thanks for the offer for support. I use TheSkyX
to control my dome and mount. Would that script interfere with TheSkyX? Meaning would I have to start
disconnecting and reconnecting from TheSkyX to do a simple pier flip function?

The observation here is, that having to write a script to perform what other manufacturers offer as default
functionality in their mounts is clunky and not seamless. Even though your offer to write a script is very kind, you
and other AP owners shouldn't have to resort to writing scripts when most if not all other manufacturers offer pier
flipping as a stock standard simple button-press feature .

I think the easiest solution will be to spend more money on more software to run (I run about 5 programs during an
imaging run already, and running another is the last thing I wanted to do). Before I spend money on APCC, does
APCC offer single touch pier flip commands for a 1600GTO with a GTOCP3 using the latest software 4.19.3?
Thank you in advance.

Thanks again for your time gentlemen, and it is evident that many AP owners cannot have access to a simple pier
flip command like most other manufacturers offer (unless we spend more money on APCC).



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