HEQ5 Pointing Accuracy

[grantboxer (Grant)]

Hi All,

does anyone know what the pointing accuracy of the Synscan controller on the HEQ5 is supposed to be and what can I do to improving pointing accuracy.

Cheers Grant

[Merlin66 (Ken)]

Do you mean the accuracy of the GOTO?
When set up properly you should achieve better than 1 min arc pointing accuracy.

[grantboxer (Grant)]

When you say set up properly, do you mean a good polar alignment and 3-star alignment?

Cheers Grant

[Merlin66 (Ken)]

Yes, exactly!

[grantboxer (Grant)]

If I do all this correctly, and still cannot get targets on my ccd chip, what should I try next?

Cheers Grant

[Merlin66 (Ken)]

What sort of errors are you finding?
Usually the GOTO is sufficiently accurate to get a target star into my guide camera - QHY5 ( via a beamsplitter on a spectroscope)
The other alternative is to look at EQMod which has the capacity to provide more "sync" points and probably even better accuracy.

[lepton3 (Ivan)]

Are you doing the alignment with the ccd, or visually through an eyepiece? I have found pointing is much better if I do the former.

[bert (Brett)]

I have found with my eq6, that I do a 1 star via Eqmod and then do a 100 point model in tpoint I can get at least 5 minute pointing anywhere in the sky.

Brett

[grantboxer (Grant)]

Thanks guys,

It seems maybe I should re-set my hand controller and make sure it does not have any old entries anywhere. I will then try the polar and 3-star alignment again. I was using EQMOD and I think I may have confused the situation.

I do use the ccd chip for alighnment in the 3-star alignment routine.

My experience on Sat night was that the goto locations were off by more than 30 arc minutes at least. That makes it quite difficult to find anything!

Cheers
Grant

[White Rabbit]

I had a he'll of a time with heq5, sn6 and eq mod Make sure that all gps corods match exactly in eq mod and your asto program of choice. Make sure the times match on the computer and Astro program and that it's accurate. Make sure you polar alignment is spot on use phd to check you alignment it's quicker than drifting. If your unsure how to do that read here http://www.iceinspace.com.au/forum/s...ad.php?t=67244

Polar alignment is everything with these mounts, 90% of my issues were solved with really good alignment.

Good luck.

[RobF (Rob)]

Agreed, good setup and great polar alignment are REALLY helpful. I had an interative learning experiece from plate solving. I started using plate solving to get correct for poor pointing, then found myself studying the plate solving situation regularly to learn what helped get better alignment. If I'm setting up somewhere for 2 days or more I now run an auto-map/sync to EQMOD using Pinpoint platesolving, but generally for astrophotography on a single object you're ok with point, sync, repoint (unless you'll be attempting automated meridian flips or something).

I would have said you're looking at more like 10-20 arc minutes accuracy, but perhaps the greater variation is just flexure in my mounting.