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

Bi-monthly release with minor bug fixes and improvements

*Progress :)* - Ekos Plate Solving not consistent

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Hi all,

I finally got to the point where I was able to test Polar Alignment with Ekos and an Olympus camera. Ekos shot the first image and solved it in about 90 seconds using Astrometry offline . I then got a message asking me to rotate the mount 30 degrees . I did so and clicked the button to confirm. Ekos then proceeded to shoot the second image and then... solver time out!!! Tried multiple attempts for the next hour or so, before giving up.

Nothing changes between the first image which is solved, and the next images which time out. Same lens so same FOV, and I even tried ASTAP with G17 database.


What am I doing wrong?
3 years 9 months ago #55338

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Well if it helps at all, I have never been able to get an image solved from around the pole...but any other portion of the sky Astrometry works 99% of the time without issues, but I use offline and have all the index files on my rpi...usually takes approx 10-15 seconds at my focal lengths.. :)
3 years 9 months ago #55346

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My manual pre-setup includes levelling the tripod; and using a compass and inclinometer app, to get my heading and elevation as accurate as possible. And based on the attached photo, it appears that I am able to achieve a pretty good alignment just by that.

Maybe that is the issue? Should I introduce some degree of error in order to get Ekos to solve? And yes, I use offline solving too.

Last edit: 3 years 9 months ago by MF.
3 years 9 months ago #55349
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I use offline plate solving for PA all the time and hardly ever have problems. Having said that, I never take such wide field images. The widest field for me is just over 5º wide and that always solves well, even around the pole. I know that some people use a PoleMaster or an iPolar for PA and that works well so it should be possible. Logs would help, as always.


Wouter
3 years 9 months ago #55353

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The trails were shot at 24mm, but I use a 80 mm lens when trying to Polar Align. Will try a 140mm when we get a clear night again.
3 years 9 months ago #55402

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With such a large field, if you assume your manual polar alignment and park position are roughly correct, you do not need to solve at all. Just slew to your target and overlook the plus/minus five degree error.

This said, I can totally understand you want to do things properly :)

-Eric
3 years 9 months ago #55411

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Yeah... I want to use upto a 600mm lens to get some long exposures of a few constellations like the Southern Cross or Orion; and I would like my PA to be as accurate as possible. I cannot use the Polar Scope on the SA due to poor eyesight.
3 years 9 months ago #55419

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I was able to run the polar alignment tool with a 50mm and a 470mm scope. I agree that solver issue starts to be really annoying :/

-Eric
3 years 9 months ago #55432

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Those are beautiful star trails.

With your imaging camera, you will most likely be best served using focal lengths between 200 and 300 mm for polar alignment.

That just has to do with the databases you use for analyzing the images. The more stars there are, the more confusing the image becomes and the longer it takes. Conversely, the smaller the FOV the more plates the solver has to interrogate until it finds the right one.
You have to find the sweet spot for your camera. The optimal FOV lies somewhere between 10 degrees and 5 degrees. That FOV ensures the pole is within the image (unless you are REALLY pointing in the wrong direction), and that there is a manageable number of stars in the image.
E.g. the Polemaster has an FOV of ~11 x 8 degrees. My guide cam of ~ 1.8 x 1.2 degrees. Both work fine for polar alignment and solve within about 10 seconds on a Pi4.

So there is a wide latitude.
3 years 9 months ago #55478

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Thank you. Will try focal lengths from 140 onward when we get a clear night again.
3 years 9 months ago #55480

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Right, did some testing again today; and yet another failure to launch :(

Switched to a 100mm lens and started the PA process. Ekos solved the first image, and the following two after asking me to rotate the mount. And then it just hung there on solving WCS (or something like that) before crashing. So close yet so far.

Rebooted the Pi, and could not get Ekos to solve even one image over the next two hours or so. Even tried with another cpoy of kstars / ekos on another USB drive.

What am I doing wrong? :unsure:
3 years 9 months ago #55722

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Hello,

With CCD, it is the image capture which is the FOV. How do I know? When I select the PoleMaster as the guide device, EKOS automatically sets the FOV to 1500x1220. If I turn scaling off under options, the FOV changes to 866x562.

I use the EKOS PA process. I get PA pretty easy now. I am wondering if N-S is being used instead of E-W to rotate. I use automated. EKOS does a good job.
3 years 9 months ago #55723

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