Question about Polar Align function

[Hy Murveit]

Keith,

Thanks for trying KStars out.

*How to use the system*
After your two slews and 3 captures, the system likely displayed some
information
(the measured polar alignment error) and instructions (to press 'Refresh'
to begin the correction cycle).
Below is a screenshot of a recent KStars/Ekos build and you can see that on
the screenshot.

[image: Screenshot 2023-12-15 at 1.14.15 PM.png]

I recommend you choose 2 or 3 seconds for the refresh, and the Plate Solve
method.
Once you click Refresh, the system will continuously capture images every 2
or 3 seconds, plate-solve those images,
and update the estimated polar-alignment error. You would adjust your
altitude and azimuth knobs to improve
the polar alignment and reduce the error. When you're done, click stop.

*Protecting the system*
As designed, the system does not protect against crashing your mount during
polar alignment.
When you start polar alignment, you input a rotation direction and a
direction and it will slew twice in the direction
you selected by the number of degrees you selected. It is up to the user to
make sure these slews are safe.

BTW, there actually is a check for crossing the meridian if the mount is
pointed away from the pole, and so it actually
protects in this way, but it does not protect against the rotations you
described. I guess it is assumed that when you do
polar alignment, you're near the mount and are supervising it. See the
screenshot below.

[image: Screenshot 2023-12-15 at 1.26.29 PM.png]

There is some online documentation about all this, e.g. see the KStars
Handbook
https://docs.kde.org/trunk5/en/kstars/kstars/kstars.pdf and you can also
find some YouTube videos online, e.g.
https://www.youtube.com/watch?v=iOp7hrxw0oU
https://www.youtube.com/watch?v=KawYjSyesq4&t=1s

If you find some doc is out-of-date, please let us know.
Hy




On Fri, Dec 15, 2023 at 11:58 AM Keith Hoard <klhoard at proton.me> wrote:

> Last night was my first night I got out with kstars/ekos.  I'm using the
> Stellarmate image on an Rpi-4.  My mount is a HEM27EC.
>
> When I was using the Polar Alignment function of ekos, it went thru its
> normal 2 RA rotations and 3 exposures.  After the last one, the system
> seemed to halt and I didn't know if it was my VNC connection or the Rpi
> since I was in backyard using home wifi.  The mount RA axis was rotated
> approximately 80 degrees westward.
>
> I clicked "Start" button again and the PA routine began to rotate the RA
> axis more westward and I was able to turn off the mount power when the axis
> got to about 100 degrees rotation.  Luckily I was right there to do that
> since the iOptron HEM mount will damage itself internally (and very
> expensively) if it is rotated past 120 degrees or so.
>
> Of course I'm checking if there is a setting inside the mount to prevent
> this from happening in the future.  However I am also curious if there is a
> setting in the Polar Alignment function that checks where the RA axis is
> before it begins slewing?  Perhaps it may be as simple as having the PA
> function begin with a "Find Home" command before commencing the RA slew
> commands?
>
> So far I am really liking kstars/ekos for control of my setup.  I started
> with ASIAir, then went to NINA/Intel NUC, and am now on ekos/Rpi-4 and
> learning the operation of the system.
>
> -Keith Hoard
> -klhoard at proton.me
>
> Sent with Proton Mail <https://proton.me/> secure email.
>
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