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INDI Library v2.0.7 is Released (01 Apr 2024)

Bi-monthly release with minor bug fixes and improvements

Celestron Nexstar + handcontoller + autoguiding

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I know this is a tired issue, but I wondering if anyone has been able to fool the Nexstar+ HC on a 6SE into thinking it is aligned, then starting EKOS and then getting a real alignment? I am currently doing this using a Starsense HC with the camera attached by first orienting the tube to the south, then performing a quick align. This works well, but it is kind of kludgy. The only reason to have the Starsense camera is so the Starsense HC will function! The Nexstar+ HC no longer has quick align as an option, indeed only Sky Align seems to be an option in wedge mode and this is too difficult when all I have are CCD cameras attached, no Finder, and a 66 year old body. I know I should really just get a new mount, but finances preclude this.
Mike
1 year 5 months ago #87819

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I don't think it is possible. This can only work without HC using the Celestron AUX driver. I don't think it's possible to connect a 6SE to StellarMate via a direct cable? IIRC, it has no PC port.
1 year 5 months ago #87861

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It is possible but requires external hardware add's to the SE mount.
The caveat is that the scope needs to be perm mounted or can be placed in roughly the same spot if not.

In video linked below:
HC has external servo motors added controlled by an ESP32 webpage, the ESP uses the servo's to push the buttons on the HC to simply do a one star north align at whatever time was last stored in the HC and whatever star was chosen by the HC.

Then mounted on the SE are position sensors wired into a PI GPIO. INDI is launched and a script is run which uses SET PROP to first move the ALT axis to the sensor, reading the axis sensor output, followed by the AZ axis to it's sensor.

Now here is where the perm mounted or same physical mount position comes into play.
The pointing of the scope when positioned at the sensors will always be in the same spot in the sky, this position needs to be determined by a plate solve. Then given we know the sky position at the current local sidereral time, the next time the scope is started we know the DEC and the RA can be calculated by using the current LST and offsetting from the platesolved initial calibration.

Using INDI SETPROP the scope is forced SYN'ed to the DEC, RA and then the current time must be forced set into the HC.

This last step of setting Nexstar time -after- it was aligned is controversial, the INDI driver as written will not allow time to be set once aligned, I needed to modify the driver to allow it to happen. Since the HC is never used for GOTO's, etc and the scope is under computer control at all times, it works perfectly.

A demo video I did of all the above:


Gene
1 year 5 months ago #87866

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Gene, that is ingenious and clearly a labor of love.
Mike
1 year 5 months ago #87867

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Thanks Jasem. I have started experimenting with the Celestron AUX driver through the USB port on the Nexstar+ HC. You are correct, the SE has no PC port. I’m using the simulator with the mount since sadly it is cloudy here. The driver is behaving a little strangely but I think that is because my alignment is off. I’ll report back later.
I could attach through the AUX port, but I would need to make a cable with the right pin out and voltage. Can you direct me to any on-line resource for this cable? I could plunge in myself, but I don’t want to fry anything.
Mike
1 year 5 months ago #87869

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Thanks Michael,

At the time (Feb 2021), the Celestron AUX was not good enough to work in Polar mode so it was a matter of necessity for remote control.
By Sept 2021, it moved from POC to live

Gene


1 year 5 months ago #87874
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Jasem,
I removed the HC and connected just with a SkyPortal Wifi adapter. This removes any effect of the HC. I determined that I have no idea what I am doing with the Celestron AUX driver. I sync to a location which agrees with the mount position (I'm using the simulator for this), But then subsequent GOTO positions on Kstars and the position of the mount have nothing in common. Clearly I'm missing something in the driver set up and/or initialization. I have a wedge mounted Celestron 6SE so I select the Equatorial Mount option. Other than the initial set up of communication, I have not modified any parameter in the driver. I begin the alignment process with the OTA pointing north.
Mike
1 year 5 months ago #87885

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For Celestron Equatorial Wedge driver, the tube must be facing south pointing exactly at the Celestial Equator.
1 year 5 months ago #87889

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I see also that I need to cycle the power for the encoders to be reset to zero. Simply restarting the driver does not do this. But something else is still missing. Do I need to manually input the RA and DEC for the initial position so KStars knows were the scope is pointing on power up?
Mike
1 year 5 months ago #87894

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I think I may have gotten it through my thick head. I used the "Evolution Wifi Wedge" driver (are these drivers different from one another, or are they all just Celestron AUX?). I set the Mount Type to AltAz (maybe it doesn't matter?) Then I set the OTA to the south at the Celestial equator. Cycle the mount power and connect to EKOS. After this, I move the mount using EKOS and sync three points (recall I'm using the CCD simulator for now). Then the GOTOs seem to be correct. On the next good night I'll test this for real. Meanwhile, I can work carefully on an AUX cable with TTL levels. I don't really like using the SkyPortal Wifi module because of its rather poor range.
Mike
1 year 5 months ago #87895

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Hi Jasem,

Please check, from what I see after compiling the latest AUX driver is startup seems to be assumed to be NCP but if a SYNC is done after startup this implies scope can be pointed anyplace(?)

if (configMountType == EQUATORIAL)
SetApproximateMountAlignment(m_Location.latitude >= 0 ? NORTH_CELESTIAL_POLE : SOUTH_CELESTIAL_POLE);
else
SetApproximateMountAlignment(ZENITH);

If equatorial, all internal calcs are done based on a rotation around the latitude - 90
TDV.RotateAroundY(m_Location.latitude - 90.0);

Gene
1 year 5 months ago #88003

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I had a chance last night to try again with my wedge mounted 6se with the Celestron AUX driver connected through the Nexstar + HC USB port. I start from power up with the OTA pointed South at the celestial equator. Polar alignment has been completed using a Polemaster mounted on the pier. The driver is set to EQ mode. From here I can successfully Sync to that point. Tracking is on. Then I move the OTA using the EKOS mount controls to a new position and attempt to sync. This fails because apparently tracking is not working and I get star trails. I get the same result in ALT AZ mode, but I expected that. Any thoughts?
Mike
1 year 5 months ago #88204

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