Polar aligning an ALT AZ EQ6

[almcl]

Been using my ALT AZ EQ6 for some months now and love the belt driven quiet movement and, when well polar aligned, the guiding accuracy is pretty good, too.

One thing however is a problem.  To adjust the position when polar aligning (has to be done every session as I have no permanent set up) I find it necessary to undo the clamps, so that polaris can be moved to the appropriate point on the circles (new style SW reticule).  So far, so good.  The problem that now rears its head is that tightening the clamps moves polaris out of the carefully set position, sometimes by quite monumental amounts.  This is most noticeable when tightening the primary locking shaft, which absolutely has to be slackened or the AZ adjustment bolts don’t achieve anything.

Not sure if this is a ‘feature’ or if something is wrong with my mount assembly, but would like to know if anyone else suffers the same issue?  Or better still has overcome it?

[newbie alert]

If you're in parked or home position then that should be where you start doing the PA..i don't even turn the mount on until PA is done..i use a different mount thou

[Starlight 1]

Yes this mount is not very good at holding polar I do have a plan after my mount get to a year old , but having prob with my mount so it may have to go back still .

[Freddie]

When you refer to undoing the "clamps" which clamps are these? I assume not the ones that disengage the drives on RA and DEC.

[carastro]

Quote

When you refer to undoing the "clamps" which clamps are these? I assume not the ones that disengage the drives on RA and DEC.

Yes I was wondering that too, if that is what you are doing then this is incorrect.  Polaris needs to be got into the reticule in the little circle on the big circle (at the right position for the date and time) by using the adjustment bolts both latitude and Azimuth - never the RA and DEC clamps.  Or if you have the new style recticule to the correct position on the clock dial.

Can you please clarify how you are doing PA?

Carole 

[Freddie]

Exactly my thoughts based on the wording but I didn't want to immediately assume the OP had a misunderstanding of what is required to PA, particularly in light of the good guiding comment.

[almcl]

Sorry if my description wasn't clear,  I am not slackening the clutches (honest!) but rather the fork tightening knobs (as per the SW instructions):

 

 

and the primary locking shaft (the one that clamps the mount to the tripod). With it tight the azimuth adjustment knobs (arrowed in red below) struggle to change orientation :

 

The 'new' reticule makes any movement pretty obvious, but tightening the locking shaft frequently produces movements like that of the two black dots here:

 

[Freddie]

That's good to hear !!

Can't comment directly as I have NEQ 6 but have never had a problem adjusting az with my locking shaft pretty much as tight as I can get it. I have heard of some people haveing some PTFE between the tripod and mount to give it less friction between the two surface which may help you on that axis.

[almcl]

Thanks, Freddie,  yes I have considered some grease or possibly a slip ring cut from a large milk container (got these in several places, now) between the tripod and the mount base...

Might have to try this.

[wimvb]

I have that problem with the bottom screw (affects az), but not the alt locking bolts. Two possible remedies:

1. I've seen a youtube video where one guy put teflon tape between the mount and tripod head. Haven't tried this myself.

2. If the shift is repeatable, give the mount an offset that will put it in the right position when you tighten the bolts.

If you tighten the az adjustment screws, you don't have to tighten the central bottom bolt that much. Don't try to overtighten it.

[newbie alert]

I have 2 Teflon sheets in between to glide rather than judder when using the az bolts

[almcl]

Thanks, Wim.  Glad to know it's not just me!

I've tried the offset technique you describe, also smaller and smaller 'untighten-shift-retighten' increments but probably down to operator ham fistedness these aren't always repeatable, although on some days we get down to less than 5' PA error, others it can be 15 or more.

[wimvb]

5 hours ago, almcl said:

Thanks, Wim.  Glad to know it's not just me!

I've tried the offset technique you describe, also smaller and smaller 'untighten-shift-retighten' increments but probably down to operator ham fistedness these aren't always repeatable, although on some days we get down to less than 5' PA error, others it can be 15 or more.

... and on those nights you wish you had a pier, right? 

When I do PA with the synscan, I use a barlowed 10 mm eyepiece with homemade reticule. I can keep the alignment star on the crosshairs when I tighten the bolt. But it has to be done gently, so as not to overtighten the bolt. Using teflon between the mount and the tripod has its plus and minus: it will make it easier to adjust AZ for polar alignment. But that also means tha PA will shift easier afterwards, and you need to tighten the central bolt more. So, it's not self evident that teflon will work. As with anything else astro-related: experiment.

[johnrt]

The fork tightening mechanism on these mounts is terrible for locking down your mount for polar alignment. If your mount will not adjust with the hand turned nuts done up tight then you are lucky, mine moves around as if they are not there. 

To try and lock it down I replaced with penny washers and nylock nuts I can tighten with a spanner, and even then I can still adjust the altitude on the mount without slackening the nuts off!

This has been a real issue for me as I am trying to lock down my PA on a pier that has the view of Polaris blocked for 8 months a year by trees & restricted horizons for drift alignment. 

I’m afraid I can’t offer any more practical advice, as the altitude adjustment mechanism on the AZEQ6 is garbage. 

[Ouroboros]

almcl  - I too experience this problem. Like others I tweak the alignment and tighten the bolts iteratively until polar alignment is achieved and the mount is secure. It's a very common 'feature' generally of mechanisms requiring fine adjustments followed by some kind of tightening procedure. I have the same problem with the focusing on my ed80 telescope. I get the scope nicely focused then tighten the fixing bolt and it's gone out of focus. 

[spaceman_spiff]

I do the altitude adjustment first and then tighten the clamps. I then sort out the azimuth adjustment. The mount holds polar alignment very well for the rest of the night.

Dan.

[wimvb]

Same for my sw 150pds stock focuser when I used manual focus. Tightening the lock screw defocused. A motor focuser solved that problem. Motors work like non-locking brakes. I've thought about adding motors to the az/alt adjustments for automated polar alignment, but it doesn't seem practical.

[gorann]

I have come to realize that this is what we have to live with when buying "affordable" mounts from China. I had this "mechanical problem" with my NEQ6, which now sits as a backup in the cupboard, and I still also have a bit of it with the EQ8 (not to mention the backlash). Still, it is manageable although ideally I should not now sit with two SW mounts but should have gone directly for something like a Paramount or Mesu. But then I know in the back of my mind that I would probably never have even contemplated going into astrophotography if it had involved 5000+ Euro just for a mount.

[Merlin66]

Goran,

Bang per buck the SW mounts work well.

I have and use the HEQ5pro (solar) and the NEQ6pro (pier mounted - C11 plus spectroscope). I can achieve subs >10min easily and successfully hold a target star image on a 20 micron slit plate.

Works well for me.

 

[wimvb]

Even if the az eq6 adjustments have their issues, as @johnrt reported, at my latitude I just can't use the standard skywatchers eq mounts. When I bought the mount, I also considered the eq6 with a wedge. Don't know if that combination is mechanically any better.

[gorann]

10 hours ago, Merlin66 said:

Goran,

Bang per buck the SW mounts work well.

I have and use the HEQ5pro (solar) and the NEQ6pro (pier mounted - C11 plus spectroscope). I can achieve subs >10min easily and successfully hold a target star image on a 20 micron slit plate.

Works well for me.

 

Yes, they work for me too, and I have no current plans for selling my car to be able to do 30 min unguided exposures. If it was not for companies like SW I expect there would be much fewer of us imagers here on SGL.

Cheers

[newbie alert]

2 hours ago, gorann said:

Yes, they work for me too, and I have no current plans for selling my car to be able to do 30 min unguided exposures. If it was not for companies like SW I expect there would be much fewer of us imagers here on SGL.

Cheers

Without these budget suppliers half of us wouldn't even be doing astro..opened it up affordable to the masses..