Maybe I am wrong here, but I think if you are using a wide angle camera like the QHY polemaster (11x8 degrees) and just point it towards the North Pole you should catch enough cricumpolar stars to allow polar alignment with the polar alignment tool in Ekos. Only if you have a narrow field and bad visibility you probably might still have problems.

Let me know fhat makes sense. As long as the solver can find something, the alignment tool should work, I would think.

Jo

Hi Jo

That’s a very good suggestion.

In fact I have a wide FOV because I use hyperstar with a C925 EdgeHD and a DSLR, so I can have several degrees of sky covered in one shot.

The issue is that Polaris is very low here, at roughly 5 degrees above the horizon and isn’t always seen because of clouds. Besides, I suspect the apparent position of the refracted pole would cause alignment errors.

That’s why I prefer an alignment method that doesn’t require direct watching Polaris, if possible.

Alfredo

Thanks Gilles

How big would be the error with this approach?

Clouds are indeed a problem. Otherwise it should not matter whether you see Polaris or not, as long as you see other circumpolar stars and the solver can recognize them.

It may work with a normal 50mm lens on a DSLR mounted to your dovetail. Generally, the closer your chosen alignment star is to the pole the smaller the alignment error should be in the end because of the earth's rotation between measurements and mount adjustments. The largest error would result if you measure near the Zenith in your case.

Does that make sense?

I don't know !
I've just noticed that when moving ALT/AZ knobs on final step, it's harder to reach target

it was just a one time test :
And I'm affraid i'm not able to reproduce with simulators
Impossible to solve first frame whatever i do.
Need to think again to what i've done before ...

Gilles.

Edit : i think i've found
Polar assistant can be done only with declinations between 60° and 90°
Otherwise solver will fail each time.
This limitation is certainly to make polar assisant go faster, but it might be increased somewhere for specific locations like you

It totally makes sense. Thanks. I'd have to try and see how accurate are the results.

This is good enough. Gilles!

At a declination higher than 60 degrees could work from here.

If you speak french, i've shared that with my forumates :

Thank you very much for this video Gilles!

I really appreciate you took the time to make the video. I could watch it with the subtitles on and translated to spanish (youtube tool). Is now much clearer for me. I'd have to try it once the weather cooperates here.

This is one of the best responses I've received on the astronomy forums.

Best regards,

Alfredo

You're welcome

I was not aware that youtube could translate like that : Crazy !

What i said before about limitation to 60-90° is wrong :
In fact, you can also use radius option of solver to perform such an alignment (but it is slower...)
Here, it will solve within 90-30° range :

Good!

Question: I have downloaded the astrometry.net local copy to my laptop. How can Ekos to be told to use it?