William Optics wedge declination screws

[AstroNebulee]

Hi

I have a William Optics high latitude wedge for my az gti mount and when polar aligning the Dec I find it hard to adjust the knurled screws as there's a bit of weight on the wedge and it's tough to get them to turn easily with clutch off. I'm wondering are there different bolts I could use that have bigger grips on them to make turning them to adjust declination during pa easier. 

Cheers 

Lee 

Edited March 5, 2022 by AstroNebulee

[RayWUK]

I had exactly the same problem. The solution i found was to move the plate carrying the mount further up the wedge so when in the 'home position' (pointing towards Polaris) the mount and scope balances more over the centre of the wedge. Makes altitude adjustment a lot smoother and less strain on the bolts.

[AstroNebulee]

2 minutes ago, RayWUK said:

I had exactly the same problem. The solution i found was to move the plate carrying the mount further up the wedge so when in the 'home position' (pointing towards Polaris) the mount and scope balances more over the centre of the wedge. Makes altitude adjustment a lot smoother and less strain on the bolts.

Thanks Ray, like the idea but I have a small blue plate attached to the underneath of my az gti and can't move it up any. I woukd if thought there's some sort of different bolts with bigger heads in the or replacement knobs to fit over the knurled ones. 

[AstroNebulee]

I've been searching and seen these on fleabay and the amazon jungle but don't know what size to get though. 

 

[RayWUK]

Ah, i bought one of these from FLO 'Astro Essentials Vixen-type Photo Dovetail Bar' they come in different lengths, mine is about 13cm long and does the job. 

I think having a bigger knob without addressing the imbalance will put a lot of strain on the threads and may eventually strip them. Better to balance the load IMO.

Edited March 5, 2022 by RayWUK

[Elp]

I don't find it too bad to turn, just loosen the opposite bolt until thats turning freely and it's easier to turn the one you want, also it's always better to adjust the altitude from top down (ie be up over your target to begin with and lower it down as you're not acting against the mounted weight). It's a bit more difficult when you're less than 1 arc minute to adjust as even the slightest micro turn on the adjustment bolts makes a huge difference. I tend not to clamp either axis after PA.

[Rusted]

Some of our local DIY, big shed stores sell assorted thumb wheels and knobs.
Take along your original thumb screw to ensure the threads match.

Balance is just as important to an altaz as it is to an equatorial.
That's an awful lot of stuff perched [un]balanced high on top of a very little mounting. IMO.
Worse, the mass is offset relative to the very narrow base.

With all mountings it is the smallest cross section which matters under load.
Your whole system is a compound pendulum. Look it up.
I'm sorry, but I really wouldn't start from here if you want steady support.
Which is exactly what that altitude screw is trying to tell you.
In case of doubt: I have been overloading telescope mountings for over 60 years.

[AstroNebulee]

Thanks for all your help guys, sorry if I'm sounding thick, so I have to move my scope up a bit in the direction the arrow is pointing so the whole load is more over the central tripod extension? 

[Rusted]

Ideally an equatorially mounted telescope is balanced around a point at the crossing of the mounting axes.
If it were not balanced, then the nose, or tail of the scope, would rise or fall. It shouldn't do either.
If it were not balanced then the counterweights, or the OTA, would rise or fall.
Again it shouldn't do either.

This image shows the crossing of the axes. Polar [RA] and Declination.

The vertical line represent a perpendicular dropped from the crossing of the axes.
The horizontal line shows the offset [or distance] of this perpendicular line from the tripod head.

This offset represents a turning force trying to tip the tripod over.
It also applies an increased force against the altitude adjustment screw.

[AstroNebulee]

6 minutes ago, Rusted said:

Ideally an equatorially mounted telescope is balanced around a point at the crossing of the mounting axes.
If it were not balanced, then the nose, or tail of the scope, would rise or fall. It shouldn't do either.
If it were not balanced then the counterweights, or the OTA, would rise or fall.
Again it shouldn't do either.

This image shows the crossing of the axes. Polar [RA] and Declination.

The vertical line represent a perpendicular dropped from the crossing of the axes.
The horizontal line shows the offset [or distance] of this perpendicular line from the tripod head.

This offset represents a turning force trying to tip the tripod over.
It also applies an increased force against the altitude adjustment screw.

Thank you, I do have a longer dovetail bar at hand so will change it over and then I should be able to move the whole setup to be inline with the centre of the tripod 

👍

[AstroNebulee]

I've been fitting the astro essentials dovetail bar and can see what you all mean, the declination bolts turn much easier now, thank you for your help. 

 

 

Edited March 6, 2022 by AstroNebulee

[Rusted]

1 hour ago, AstroNebulee said:

I've been fitting the astro essentials dovetail bar and can see what you all mean, the declination bolts turn much easier now, thank you for your help.

I think a more accurate term would be "polar altitude adjuster." [Or PA thumb screw]
But then I'm a pedant.   Not to be confused with peasant. Which is also true.