Extension shaft for EQ Mount HEQ5

[astroboyz]

Hi all,

I'm sure this topic comes up every now and then and I've seen several posts that people made their own. However, I've been struggling to find one for myself due to lack of skill/tool. Any advice where I can get one, happy to pay if someone can make one for me.
I have attempted to contact www.scopesnskies.com several times regarding to their product, with no response.

If you have tool, why not make couple dozens and sell them here

Many thanks.

[glend (Glen)]

My NEQ6 Pro came with an extension shaft. Are they the same size? You might be able to find someone who would sell their extension.

[MattT]

IIS member Trevor Hand used to make them, don't know if he still does.
Send him a PM.
Matt

[raymo]

I'm curious to know why you need to extend the shaft, when the supplied weights will balance a load that takes the mount very close to it's
recommended max. A small [750gr] weight mounted above the supplied ones will take the mount to it's max. for visual use, and well beyond the
recommended max for imaging work. If you are imaging, and need to extend the shaft, it looks like you should have got the NEQ6.
Incidentally, If you are only looking for a little extra effective weight, configuring the weights so that the larger aperture on
the bottom weight is at the bottom, will allow the weight to slide down further so that the retaining bolt on the end of the shaft is up inside the bottom weight.
raymo

[MattT]

I got the extension instead of buying a 1.25kg Skywatcher weight. I needed to move the 2 5kg weights down about 4cm which I thought was better than buying another weight. What's better longer bars less weight or more weights and a shorter bar? I did have an Orion Skyview Pro EQ5 that had a longer weight bar than the HEQ5 pro
Now I prefer more weights and a shorter bar on the NEQ6, I only do visual.
Matt

[astroboyz]

Hi Raymo,

I was surprised too when I tried to balance wrong tube they sent me last week. With 2 counter weights right down the bottom of the shaft, I could not balance the 9.2kg weight (tube+28mm eyepiece) on the RA axis ! (i.e. the tube was balanced on the DEC axis). It was a quick test because I had to return the tube; it could be something that I did wrong. Let me try again once I got the new tube. Many thanks for the info,.
The idea of getting the extension shaft is to have less than 11kg counter weight, it may or may not work out though :-)

[mithrandir (Andrew)]

Mounts are rated for the OTA and attachments, not including counterweights.
By lengthening the couterweight shaft so you don't need extra weights you increase the moment of inertia. You probably should reduce the slew speed to reduce stress on the motors.
The ideal is to have the counterweights as far up the shaft as you can put them and still balance.

[astroboyz]

Hi Andrew,

I agree with weight rating of the mount. However, I'm trying to lower the load-to-max_support_weight to about 50% for AP. I'm currently stuck with my 8" Newt OTA, which together with other attachments total up approx 11kg.

Assuming that I can balance this load perfectly on my HEQ5 Pro mount with the two 5kg counter weights, the load is 78% of max weight, which would be too much strain on the motor.

My logic could be wrong, but by moving the counter weight further out 14cm using extension shaft, I can effectively reduce my counter weight from 10kg to around 7kg (i.e. using one 5kg and one 2kg counter weight)... 3kg less on the mount motor! This has the same effect as reducing 3kg on the OTA+attachment and the load percentage is now approx 54% instead of 78%.
The HEQ5 Pro mount has 20cm shaft, while the Celestron AVX has 30cm shaft, so I think it's worth a try :-)