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Old 24-06-2020, 06:53 PM
Starpaws
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Starpaws is offline
 
Join Date: Jan 2007
Posts: 1
Skywatcher 12" Dob with Goto .. 2 star alignment accuracy VERY poor.

OK. We have the Synscan goto, and the 2 star alignment is not working, in the sense that the accuracy is VERY poor. The scope is brand new, only a few days old. It had this problem right from the day 1.

To cut a very very long story as short as I can make it ...

I complete the 2 star alignment up to where I enter the name of the second star. It tells me where it thinks the second star is, and it goes there.

But it is out by several degrees.

Using the controller, I manually point it to the second star and tell it what it is looking at. It tells me Alignment Complete and then says CAUTION..... THE PREVIOUS VALUE FOR NPE IS APPLIED ....

But ... it is not working. As far as I can tell, it is insisting that the second star is where it thought it was in the first place, and not where I tell it it is. All of the pointing from there on is based on where it thinks the second star is.

Maybe an example.

I find Arcturus as the first star.
I tell it Alpha Crucis is the second star. It goes say 4 degrees East of it. I manually move it to Alpha Crucis and it says it is aligned.

If I tell it to find Arcturus, it goes reasonably close to it.
If I tell if to find Alpha Crucis, it goes to where it initially thought is was, 4 degrees East. So it is as if it hasnt accepted my manual movement

If I tell it to find say Antares, roughly half way between them, then it goes (somewhat predictably) 2 degrees to the east.

So the star sphere as it THINKS it is compared to what it really is, seems to be rotated by several degrees around where my first alignment star was.

If I tell it to go to Arcturus, the first star, it goes very very close to it.

The software version on the controller is 4.39.04
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