how do I do east heavy?

[alacant]

Hi

I've an eq6 with 3 x 5kg counterweights up against each other. Let's say I have balanced in RA and the counterweights are east. Could someone give me an idea as to what east heavy would be? I'm thinking in terms of moving the counterweights a certain distance east and then twice that distance back when on the other side of the meridian. I'm not sure what to look for or how one would describe how much heavier to go. Anyone?

TIA 

[vlaiv]

If scope is pointing east, move weights a bit down the shaft. If scope is pointing west move weights a bit up the shaft. It is usually enough to move just one weight and by small amount (like 1cm up or down) but this depends on how heavy your rig is. The heavier less travel is required.

[swag72]

Here's the only way I could ever remember it ..........

East heavy is when you are imaging UP to the zenith - All I used to do was move the weights down the bar by about 1cm.... then west heavy is when the counterweight bar is in the other direction after the flip and it's when you are imaging DOWN from zenith - Move the weights back up the counterweight bar and perhaps another 1cm or so.

[alacant]

Hi

It's an eq6 carrying 11 kilos of telescope.

[psamathe]

As a beginner myself, I found the easiest explanation on http://www.cloudynights.com/topic/501827-clarification-on-east-heavy-balancingplease-fill-in-the-blank/?p=6613885 "For a German EQ mount like your AZEQ whatever is on the EAST side of the mount should be a few ounces heavier than the west."

But is this correct ?  Seems a simple way to remember if it is (I am not proposing it as "the answer", just asking if it is another correct explanation)

Ian

[vlaiv]

Best way to understand this is: mount is moving from east to the west, and it should pull weight in doing so, rather than being pulled by the weight. Think of the scales, and the gravity, so you are looking at the scales and you are facing south, so scales should be doing clockwise motion (left side rising, right side going down). Which side should be heavier? One that acts against motion of scales (this case being left side, as gravity will pull it more than the right side and it will oppose the clockwise motion). So when you apply this analogy to the scope. If you are imaging stuff that is to the west (scope is pointed to the west, but it sits on east side of the pier), scope side should be heavier. If you are imaging target at the east of meridian, scope is on the west side pointing to the east, counterweights should be heavier.

Since we are not adding actual weight, same scales analogy applies here - further the weight from the pivot point - "the heavier it is", so pulling weights towards the pivot (up the bar) - weights side is "lighter", pulling it away from pivot point (down the bar) - it is "heavier".

Scope east of pier, imaging target to the west - counterweights up the bar. Scope west of pier, imaging to the east - counterweights down the bar

[almcl]

I never quite 'got' the verbal descriptions, but found this video (about 3 minutes in) helpful

https://www.youtube.com/watch?v=uK2bXfVNoQU

 

[ollypenrice]

Most astronomers know their site in terms of NSEW. (North is where Polaris is. East is where the objects come from.  West is where the Sun goes. ) So, starting with the mount in perfect balance...

1) If you stand on either the N or S side of your mount and look at it you then know which is E and which is W. (If you're S of the mount E is right and W is left. If you're on the N side of your mount then E is left and W is right.

2) You know that moving a counterweight towards the mount makes the counterwieght side effectively lighter and moving a weight away from the mount makes it effectively heavier.

And that's all you need to know. The trick is just to look at the thing and think it through. Don't try to remember anything by rote.

Olly

[alexbb]

How much? (that's what you asked) Not much. Enough that after you balance it and tight the clutches, the scope/counterweights will pull enough the mount around the RA axis in order to clear the backlash even with some wind.

For your first assumption, you're right. The point is that the mount should work against gravity, not be helped by it. So if the counterweights are helping the mount to rotate, they should be lighter than the scope (move the counterweights towards the mount so the mount lifts the scope). If they're pulling the mount against its motion, they should be heavier than the scope (move the counterweights away from the mount so the mount lifts the counterweights).

HTH,

Alex