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INDI Library v2.0.6 is Released (02 Feb 2024)

Bi-monthly release with minor bug fixes and improvements

Support of TELESCOPE_PIER_SIDE switch / meridian flip

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Dear all,

I am trying to setup a virtual version of my future observatory, and I am now trying to understand the constraint related to the use of german equatorial mount (I never had one before).

I noticed that the indi_smulator_telescope does not features the TELESCOPE_PIER_SIDE switch defined here: indilib.org/develop/developer-manual/101...ties.html#h2-general

I was wondering which commercially available mount that has a indi driver features this switch, and how is it possible to tell indi to automatically perform a meridian flip given a certain angular threshold.

And finally, is there a simulator for this ?

Thank you very much for your help
5 years 9 months ago #26584

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TELESCOPE_PIER_SIDE switch is read only, it give you the current side but you cannot set it to force a flip.
From a quick look at the source code it is in the following drivers: eqmod, lx200*, temma, ioptron.

The automatic meridian flip cannot be done at the Indi level, it is the responsibility of the capture application because you not want a flip on the middle of an exposure.
In my capture application this switch is use to check the mount state before and after the flip, but the flip itself is done with Slew command.

This property is very important for dome automation to put the opening in front of the telescope on both side of the meridian.

It is also used by auto-guiding application like PHD2 to know if it need to reverse the declination movement relative to the calibration.

You can use indi_eqmod in simulation to play with this property. After you start the driver set the option Simulation to Enable before to click Connect.

Patrick
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5 years 9 months ago #26604

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The main telescope of the club sits on a GEM (Knopf) and is driven by an FS-2. The INDI lx200fs2 driver is used when I connect my laptop (Ubuntu + KStars bleeding edge INDI-Kstars update). I have not found a TELESCOPE_PIER_SIDE switch. Until now club member users of win CdC (with the latest version no longer working with the FS2) have always manually slewed the mount, powered the FS-2 off and on again, re-acquired a reference star, synced and then manually drive the dome to align the opening with the CDK20. All rather time consuming; especially when there are visitors.

So is there a TELESCOPE_PIER_SIDE switch in the LS200* driver? It is not in LX200basic. *=? Where is it?

I am still working on the dome automation: Testing an arduino nano+HMC5883L digital compass today....

John
5 years 9 months ago #26608

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You are right, all the lx200 do not have this property. To be more precise I see it in : lx200pulsar2, lx200ap_gtocp2, lx200_10micron, lx200gotonova, lx200ap_experimental, lx200_OnStep, lx200ap, lx200gemini,.
But there is no standard lx200 command to get the pier side because the original lx200 are fork mount. So each of this driver use a specific command extension to get the pier side.
You must look at the fs2 documentation to see if such a command exist.

About your Windows users, why they not use a Ascom driver with Poth to automate the dome? but this is out of topic here, write me a private message if you are interested to develop.
The following user(s) said Thank You: Jasem Mutlaq, dolguldur
5 years 9 months ago #26612

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Hi,

I'm the author of the FS2 driver for INDI.

The problem with FS2 is it doesn't provide a pier side status in the LX200 protocol, so the driver can't know which side it is. On the other hand, in the Dome drivers, you can manually inform which side the telescope is, in order to solve this issue.

By the way, you can flip the pier side of the telescope with FS2 without turning off or realigning. Just "simply" use the pad to move the tube to north until it crosses the north pole (south if you are down under). At that point FS2 flips his internal state of the pier side and you can slew normally and it will go to the other side of the pier. And don't remember to inform to the dome driver the new pier side.
5 years 9 months ago #26624

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Hello and thanks for the information about the FS2 controller. Also thanks to pch.

So we can save some fruitless work on the lx200fs2 driver.

Nobody in the club has mentioned the technique which you have described. I will try it asap with ekos-kstars. But as you mention a dome driver, that is where we will focus our work. I met a member who is more advanced with the use of INDI than I am. His wife is a code writer so we can formulate requirements for the necessary additions.

Please take a look at my new video posting on YouTube dome digi compasshttps://www.youtube.com/watch?v=AAH8GZesRPk

The data stream from the digital magnetic compass will be integrated into INDI via a Python app to feed the data to the server and dome driver.
As this is off topic I will also post the video link under the topic of dome drivers.
5 years 9 months ago #26648

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Hello fcasarra, you said:
"By the way, you can flip the pier side of the telescope with FS2 without turning off or realigning. Just "simply" use the pad to move the tube to north until it crosses the north pole (south if you are down under). At that point FS2 flips his internal state of the pier side and you can slew normally and it will go to the other side of the pier. And don't remember to inform to the dome driver the new pier side. "

So let me check the procedure:
Using KStars first align the telescope on a reference star "Alpha whatever" in the FS2 data base.
Then engage KStar FS2 connect and sync.
Then use the FS2 hand control pad and press the N button to slew the telescope to the North Pole.
FS2 stopped the slew when it reaches North. ( I think that we saw this last time we had a chance to do some tests.)

Now the FS2 automatically flips its internal state?
If so then using KStars to select a target that is on the other side of the meridian and commanding a slew to this target should be accepted by FS2. That is FS2 will allow the slew from the north pole to the object on the other side of the meridian.

OR must KStars Ekos telescope mount control (FS2) first be set to change the side of the meridian? If so, where on which tab of the Astro-Electronic FS-2 Ekos panels is this "new pier side" command button?

Is it the Slaving Tab in the Dome-Simulator -- Meridian side ? If so it is a strange location for the FS-2. What if the observatory is a roll-roof or no roof?

We will test this tonight.
Last edit: 5 years 7 months ago by VTVL.
5 years 7 months ago #28232

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That's it.

Just two warnings.

- When you use the control pad and the telescope arrive to North Pole, it stops and starts moving in the reverse direction, because FS2 changes his internal state and North is in the other direction. So, you must be alert to stop pushing the N button once +90 was passed.

- Side pier is in the Dome driver because Dome need to know pier side in order to positioning right. If you have no Dome, you don't need to inform.

Future improvements if someone wants/have time to implement it in FS2 driver:

- Detect when FS2 croses North (South) Pole and register the pier side change.
- Add to the FS2 driver a function to flip meridian. If the movement to North was done by software I think the FS2 internal state with change also, but not sure.
- Add functionality for avoid colisions with the mount.
5 years 7 months ago #28285

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