NEQ6 alignment - help please!

[joncrawf]

Hi All

I have been waiting for a clear night to set up my new NEQ6 mount. It's new to me but I picked it up 2nd hand a couple of weeks ago. 

So far I've done an approximate polar alignment which I'll tweak and improve when the pier adaptor finally arrives from Pulsar Observatories and I can mount it permanently on my pier. However, when I start my two-star alignment procedure (beginning at the home position) the scopes slews off to find my chosen star (Vega or Altair this evening) but only points approximately in the right direction - I'd estimate I'm off by 5 degrees or more. I presume I should be much closer than this? Have I made a schoolboy error in my initial set-up? It almost seems like I might have entered incorrect info into the handset but I've double checked all of this several times.

When I use the 'park scope' function the scope returns quite happily to Polaris.

Any help would be greatly appreciated.

Jon

 

[Paul M]

The mount needs to have been put in the park position after a successful alignment or after being used in accurate alignment and then not moved either physically or by rotation of the axes while powered down. 

If that isn't the case the home position doesn't mean too much. Just center the first alignment star by either slewing with the hand control or slacken the clutches and hand ball the scope. Once centered accept it and the mount should then find the second alignment star quite accurately. 

It just needs a starting point. That can be from either an accurate parking position or by manual location of the first object. 

[joncrawf]

40 minutes ago, Paul M said:

 Just center the first alignment star by either slewing with the hand control or slacken the clutches and hand ball the scope. Once centered accept it and the mount should then find the second alignment star quite accurately. 

It just needs a starting point. That can be from either an accurate parking position or by manual location of the first object. 

1

Thanks Paul, what you say makes good sense. But I'm still confused!

If you're 'hand balling' the scope presumably the mount can't 'know' it's position until i accept the alignment in the handset? I'm confused as to why it can find it's way from the park position (pointing accurately at Polaris) to some random point in the sky in the general direction of Vega but then find it's why back to Polaris. 

Getting foggy now so I'll have to give up tonight and try another time.

 

[Paul M]

To find polaris the mount only needs to know where 90 degrees declination is. You can swing RA all over the place and still have polaris in the eyepiece. But as declination reduces RA becomes relevant. So I guess you'd start to pick up positional discrepancies pretty quickly as you slew away from the pole. 

You'd need to set the Position Angle for polaris extremely accurately to align RA near enough to use for Goto alignment.