Craig Oakley replied to the topic 'indi_celestron_aux' in the forum. 2 years ago

I am using the original Celestron CGEM with only the SkyQ WiFi module (hand controller is disconnected). My test setup is with the mount in EQ North configuration.


Craig Oakley replied to the topic 'indi_celestron_aux' in the forum. 2 years ago

I started to debug my issues with the indi_celestron_aux driver and made a major breakthrough last evening.

Please forgive my coding methods, I have been familiarizing myself both with the INDI framework and development under Linux.

To summarize the issue, it appears the indi_celestron_aux driver never initializes the motor controllers using the MC_SET_POSITION command. Both the ALT and AZM controllers have no known values and thus no home position (i.e. the mystery slew limits in RA).

For example, I added a "zero" button to the indi_celestron_aux driver. This allows me to initialize the controllers with a home position after startup.

raCmd.setPosition(STEPS_PER_REVOLUTION / 4);

decCmd.setPosition(STEPS_PER_REVOLUTION / 2);

This immediately fixes my slew limit problems. The mount now knows I am positioned at the index marks. However, this is still a work in progress.

I would like to mention two very helpful resources: Rick Bassham's indi-celestron-cgx driver and the AUX protocol document by Andre Parquette (see below).

In my early investigation, I found it easy to modify Rick Bassham's driver to support the SkyQ WiFi module without the need for a hand controller. Since my mount does not support automatic alignment (MC_LEVEL_START and MC_LEVEL_DONE), I also modified the code to manually zero the mount at startup.

Testing the mount indoors with the modified indi-celestron-cgx driver, all my primary issues are fixed. After the initial startup, I can fully control the mount through WiFi with no hand controller. I can also successfully goto any object using KStars.

I am hoping to test outdoors in the next few days; my local weather has not been cooperating.


Craig Oakley replied to the topic 'indi_celestron_aux' in the forum. 2 years ago

1) The hand controller was originally disconnected as suggested in the AUX documentation. I only connected the hand controller for testing. The hand controller is also needed during testing using the serial/RS232 interface.

2) Yes. When I first connect the AUX driver, I select the "Mount Info" tab and change the "Mount Type" to "Equatorial". The default is AltAz.

3) Yes. The "Alignment Subsystem Active" button and the "Inbuilt Math Plugin" button is green and already active after first connecting. To confirm the alignment system is active, I tried toggling the button off and then back on. I also tried the "Nearest Math Plugin".

4) After first connecting and changing to Equatorial, the mount coordinates show as 00 00 00 RA and -00 00 00 DEC.

5) After the first sync, the RA and DEC show the correct values of the star selected. This is correct for both manual syncing and plate solving.

6) The motion control is correct. i.e. "Right" moves the RA counterclockwise and "Up" moves the Dec counterclockwise. This is the same as if I was using only the hand controller without Ekos. This motion is also the same if using the Celestron SkyPortal app.


Craig Oakley replied to the topic 'indi_celestron_aux' in the forum. 2 years ago

Yes. In fact, after each slew and sync the crosshair hovers over the correct position in Kstars.

However, when performing a goto after the sync stage, the crosshair no longer matches the actual mount position.


Craig Oakley replied to the topic 'indi_celestron_aux' in the forum. 2 years ago

I was able to get in some testing last night.

I tried the "Nearest Math Plugin" with no success. The default is "Inbuilt Math Plugin".

Just to verify my setup, I went back to the old Celestron CGEM driver (indi_celestron_gps) with the hand controller and RS 232 cable. Everything works with no issues.

Then I verified the SkyQ WiFi module without Ekos using the Celestron SkyPortal app. Again, everything worked as expected with no issues.

So back to testing the Celestron AUX driver. Before every test I reset the mount to the initial configuration: EQ North with RA/Dec set to the index marks. I also reset the driver (purge configuration).

I even tried the Celestron AUX driver using the serial interface. No matter what steps or math plugin I use, the mount does not know where it is pointing. I also tried both manual and plate-solving to sync.

For example: I reset my mount configuration and the driver. Power up with the hand controller connected. With the mount pointed towards Polaris, I use the hand controller to slew to a bright star and sync Ekos with the RA and Dec coordinates. I repeat this with at least 6 stars added to the alignment set size. Then I use Kstars to goto a new star close to where I was last pointing. The mount slews far in the opposite direction.

If you would like me to test any specific procedure, just let me know.

Thanks for the help...


Craig Oakley replied to the topic 'indi_celestron_aux' in the forum. 2 years ago


Does the Celestron AUX driver have any hidden slew limits?

On initial connection, I cannot manually slew more than approximately 20-30 degrees east of North. I have no slew limits set and no problems slewing west of North.

My initial mount setup has the RA and Dec set to the index marks and counterweights pointing North. The hand controller is disconnected as suggested. I am using the SkyQ WiFi module.

After much trial and error, I found a partial work around. I initially position the telescope on the East side of the mount, counterweights facing West.

I could then manually slew to any part of the sky, but KStars was still confused as to where the mount was pointing even after a dozen plate solves. Any Goto command would point the scope to the wrong part of the sky.

So, maybe someone out there has experienced similar issues and can offer some suggestions.



Craig Oakley replied to the topic 'indi_celestron_aux' in the forum. 2 years ago

When building, which branch of the code should we be using?

"indi-celestronaux" is the most up-to-date, but still at version 0.7. "indi-celestronaux_2" is a couple days old but at version 0.8 and contains the mount type switch.



Craig Oakley replied to the topic 'Celestron AUX 2nd try' in the forum. 3 years ago

I am using the All Star polar align utility that comes with the Celestron CPW software; using 6 calibration stars. I have a polemaster but at 360 mm focal length, the all star is close enough.


Craig Oakley replied to the topic 'Celestron AUX 2nd try' in the forum. 3 years ago

I'm curious if anyone has made any progress using the Celestron AUX driver on an EQ setup?

The device page for the driver states the "driver was tested with NexStar Evolution (Alt/Az) and CPC (EQ) mounts".

I have spent several sessions over the past few weeks with some success. The major problem remaining is the alignment is off; despite initial success with solving and syncing.

My setup consists of a Celestron CGEM mount with the SkyPortal WiFi module. Connecting and controlling the mount works correctly, but pointing accuracy is erratic and inconsistent.

I tried following the recommendations of the driver's author (Jochym) from a previous thread:

Celestron SKYQ Support

This involves activating the alignment system and using the built-in math plugin to sync on stars in a triangle. However, the thread was using the older NexstarEvo driver.

Some interesting things I discovered in my testing:

- Since the driver doesn't know the correct home position and the mount's pointing gets worse over use, I found parking the mount at the start, and then moving the mount to the index marks before unparking, allowed me to set and quickly reset back to the home position (North/Polaris).

- Although I am not using any limits, the driver will stop when slewing left of West. No such problems in the East.

- After syncing on multiple stars, I will eventually get the message: "Alpha matrix is singular and cannot be inverted".

In the meantime, I have been using INDI to image and Celestron's PWI to control the mount.



I am using the Celestron NexStar Evolution driver on a Celestron CGEM mount using the SkyPortal WiFi module. The other Celestron NexStar driver does not support WiFi.

I am successfully connected to the mount using the access point mode (port 2000) and can even control the mount (slew, goto, park).

The only problem, the driver thinks the mount is in Alt/Az mode.

Is there any way to switch the driver to the CGEM's equatorial (Eq North) configuration?

Thanks in advance for any help.