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Mount is parked after polar alignment - why?

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Hi,

I am just now able to try out Kstars 3.3.6, after having used 3.3.4 for some time. Everything is good, except for what happens after the polar alignment procedure. I go through the mount adjustments, then click "Done", and the mount starts moving. The first time this happened, I panicked, but it turns out the mount was apparently commanded to park. This behaviour is different than the previous kstars/EKOS behaviour, in which clicking "done" just stopped the image looping and left the mount where it was (either RA +60 or -60 from zero position).

I don't like this. I never park my mount. A CEM60 wants you to power off the mount after it is parked - I don't want to do that for lots of reasons, not least of which is why should I power cycle my mount just because I polar aligned it? Parking means end of the night, not just another step in getting ready to image.

Anyway, perhaps I'm doing something wrong, or have missed an option somewhere. Thanks for any help with this.

Best,

Charles Wright
Ubuntu 18.04 and Raspbian Jessie; INDI 1.7.4
Mounts: CEM-60 chiefly; iEQ45
Cameras: Atik 383L+, QHY5-II-M
Focuser: Moonlite
3 years 4 months ago #43670

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You can turn it off in the astrometry.net settings "Auto Park". The mount parked to enable you to repeat the experiment from the exact location in order to minimize any errors in the measurement.
Jasem Mutlaq
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The following user(s) said Thank You: Charles Wright
3 years 4 months ago #43672

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I hadn'nt even noticed that setting before (and it wasn'n mentioned in the config file until I unchecked it)

Given that the park position can be anywhere, and not pointing to the pole, it might be reasonable to not activate it by default?
Also, in that context, how about being able to start with CW horizontal and doing 3x60⁰ rotation? In my experience circle fits get much more accurate, the more of the circumference the data points cover.

@TO: You don't have to power cycle the CEM after parking, you can just unpark it from the software. It's only the hand controller that insists on you power cycling the mount (and usually I don't even have that one connected)
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI2600/1600/290mini+EFW+EAF
The following user(s) said Thank You: Charles Wright
3 years 4 months ago #43678

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Thanks, guys, this will be helpful.

The CEM60 leans heavily on "zero position" (pointing at the pole with telescope vertical) - or maybe I do, since the hand controller insists on you powering off the mount after a park. I have not tried setting a park position in EKOS, thinking that would do the same thing.

My method has been to run the polar alignment several times, starting at zero position and returning to zero position after each run of the procedure. I don't have a permanent setup so I do this frequently.

I like the idea of rotating in RA more than 30 degrees during the alignment process, and also the idea of taking the images from both sides of the mount. Tell me if this is a good idea:
1) Set a park location with an RA 60 deg east and the scope pointed at the pole.
2) Run the polar alignment process, moving 60 deg west each time
3) Auto-park back to the first position

What do you think?

Thanks again for the help,

Charles
Ubuntu 18.04 and Raspbian Jessie; INDI 1.7.4
Mounts: CEM-60 chiefly; iEQ45
Cameras: Atik 383L+, QHY5-II-M
Focuser: Moonlite
Last edit: 3 years 4 months ago by Charles Wright.
3 years 4 months ago #43688

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I would completely leave park position out from this procedure. You don't know where it is, and you don't want to change what the user has set it to.
It should have a (definable) start point, and just return to that point once the procedure has finished. Maybe hour angle is a good basis for that?
openSUSE Tumbleweed KStars git INDI git
GPDX+EQMOD, CEM60EC, ASI2600/1600/290mini+EFW+EAF
3 years 4 months ago #43689

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Hi again,

The procedure worked great, I think, but now I have a conflict between the results from the polar alignment tool and PHD2's Guide Assistant.

I did not bother with parking; just used the HC to turn the mount to 4 hours east by the hour angle reading. I don't have any screen captures or logs, but I recall the measured polar misalignment was less than an arcminute. I've repeated this procedure several times, each time the error vector is very short (~ 10-20 pixels long), and it's difficult to make any improvements. With my image train I'm running at 0.63 arcsec/pixel, if that helps.

When I use PHD2's Guiding Assistant, it tells me the misalignment is ~ 7 arcmin. I have to wonder which measurement is correct. My guess is that PHD2 is more correct, since I can watch the DEC error slowly increase over time. If anything, maybe their scale factor is wrong, but I sort of doubt it.

Anyway, perhaps I should start a different thread on this, but I'd be interested to hear any advice. I'll get back with screen captures and logs next time I go out.

Thanks,

Charles
Ubuntu 18.04 and Raspbian Jessie; INDI 1.7.4
Mounts: CEM-60 chiefly; iEQ45
Cameras: Atik 383L+, QHY5-II-M
Focuser: Moonlite
3 years 4 months ago #43783

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