NEQ6 Counter Weights

[Tinker1947]

I have 4 weights on the bar and its not quite enough, i have added the extension bar and pushed the original bar back inside, this now has 2-3" sticking out to gain balance the stuff its balancing is, 10" Newt, ST80 with guide rings and Lodestar, Moonlite focuser with a Canon 600D inserted, Telrad, it will be getting a Astrozap Dew Shield, so the question is will the mount take a 5th weight so i can shorten the amount they stick out.....I know pushing the bar back inside will block the hole used for PA but i do it via the handset or EQMod......

[steppenwolf]

Hmmm, I'm surprised by this, in days of old, my first imaging rig comprised an EQ6, 250 SPX reflector, ST 80 Guide 'scope, Canon EOS 300D and a Toucam for guiding. My old EQ6 was made before they supplied an extension bar and I only required three of the standard weights! Most strange.

My ST 80 was piggy-backed on the Newtonian, making for the worst case scenario.

I have had a fourth weight on the retractable shaft when hefting a larger 'scope got a review but never a fifth.

Perhaps I was just happier with the weights lower down on the shaft than you are?

Sent from my iPhone from somewhere dark .....

[Tinker1947]

I would like the weights as close to the mount as possible makes for more room when they swing in what a Estate Agent would describe as a very cosy Obby...when it was out on the patio there were only 2 weights on the extension bar one right at the end and one around 2/3rd of the way down......

[Earl]

you will need the bar at full extensio for it to counter balance, i had the same gear more or less and never had more than 4 weights to get balance.

[Tinker1947]

I think i had it fully extended, will test it again.....

[steppenwolf]

Aha, that makes sense if you are looking for a short counterbalance extension. There is a bit of a balancing act (oops, pun) between moment arm and total weight and there is much to commend a short moment arm but I would be reluctant to have five standard weights on my EQ6 (that's 25kg) but to be fair, I have no real life data to back up my concern!

Sent from my iPhone from somewhere dark .....

[Tinker1947]

Its close with 4 and how the bar was extended, it will be tomorrow before i can check the bar was fully extended, but there's no rush i think its cloudy all next week.....

[Carina Lass]

I don't care how cozy the obsy is, if you want decent action use the bar extended and use less weight

[Tinker1947]

Well back to cosy, nice one Earl the bar must have been part way in, while there at the end its balanced ok, just ordered a mobile step stool so i can see through the EP without reducing the pier height......

http://www.amazon.co.uk/dp/B000SHUDHK/ref=pe_385721_37986871_TE_item

[Earl]

Result

[laser_jock99]

From an engineers point of view the most stable situation is to have the counterweight mass as close to the mount as possible. With big scopes this will mean buying more counterweights rather than using the extension bar- which should really only be used as temporary solution. 

If the scope is really heavy then the entire counterweight bar may only just be long enough for all the weights!!

[Tinker1947]

I have ordered the 5th weight today, as the extension bar is right out and when the scope faces East the weights are North and the space between them and the wall is just to narrow for me to get passed the 3-4" the bar can go in will allow me to pass with out going on a diet...this also goes along with what Laser Jock has typed....

[laser_jock99]

I have ordered the 5th weight today, as the extension bar is right out and when the scope faces East the weights are North and the space between them and the wall is just to narrow for me to get passed the 3-4" the bar can go in will allow me to pass with out going on a diet

My main worry is bashing my swede on them in dark.......

.....believe me it hurts!

[Tinker1947]

I bump into mine when the roof is closed in normal use there waist height........

[LeeB]

thats steel tubes for you, I run a 12" OO F5.3 with extras, and only need three weights and no extention bar, the weights don't even need to be all the way out on the bar.

[laser_jock99]

A carbon tube upgrade would be nice- I found a guy in Germany selling them pre-drilled for the GSO 12" F4 newt. Was about 500 Euros though.......

[Tinker1947]

The weight ordered from FLO yesterday has arrived along with the Kickstool, so i can look through the EP when its pointing upwards, i suspect its 7-8' above the floor level......pictures may follow...

[ollypenrice]

I don't care how cozy the obsy is, if you want decent action use the bar extended and use less weight

I disagree with this, as does Steve in his earlier post I suspect. The balance factor moves linearly with distance but the angular momentum rises with a square, so more weights closer to the mount present a lower moment than fewer weights which are further away. Usually it is an excessive angular moment which causes problems. On the other hand, check out Laser Jock's counterweights. He must hold the world record! (Mind your toes as well as your head, LJ!!!)

One small thing, but many Newt imagers have the camera and focuser rotated to the mount side. If you haven't already done this it would slightly reduce your C/W requirement.

Olly

[laser_jock99]

One small thing, but many Newt imagers have the camera and focuser rotated to the mount side. If you haven't already done this it would slightly reduce your C/W requirement.

Olly

I think I tried that once but it causes some other imbalance on the declination axis?

EDIT- Inertia is something rightly to wary of with a loaded mount. 

[Earl]

im struggling with counter weights to balance my dec, i cant sit high in the saddle so have to weight the glass end.....

[Tinker1947]

I disagree with this, as does Steve in his earlier post I suspect. The balance factor moves linearly with distance but the angular momentum rises with a square, so more weights closer to the mount present a lower moment than fewer weights which are further away. Usually it is an excessive angular moment which causes problems. On the other hand, check out Laser Jock's counterweights. He must hold the world record! (Mind your toes as well as your head, LJ!!!)

One small thing, but many Newt imagers have the camera and focuser rotated to the mount side. If you haven't already done this it would slightly reduce your C/W requirement.

Olly

I always thought the Newt needed balancing on the vetical by turning the tube so the tube never went left or right, this puts my focuser right on top, it lines up perfectly with the 2 studs that take a dovetail bar for the guide scope.....????

[laser_jock99]

I have always find the declination axis much harder to balance than the RA axis. Having a weighty camera off to one side won't help as it it's not always as simple to re-balance. Sliding the tube up or down the rings or moving the dovetail on the puck doesn't always work. I like to keep things in straight lines!

[Earl]

getting good balance on a newt with camera attached requires rotating the ota and have all the cluthes loose. its fun

[ollypenrice]

The camera orientation I mean has the camera chip/screen parallel with the flat side of the counterweights and the tube rotated to put the camera as close to the counterweights as possible. A pic would be easier, but  this is what the expert Newt guys do. Here's Pieter Van de Velde's self built fast corrected Newt gracing one of our patios. http://www.astronomie.be/pieter.vandevelde/equipment/2014_provence.jpg

Olly

[ollypenrice]

im struggling with counter weights to balance my dec, i cant sit high in the saddle so have to weight the glass end.....

This is a Tak with capstan, I see. This means the focus knobs rotate when you want to rotate the camera, so you can't slide the scope forward without blocking the rotation. WIth Tak's more rearward mounted rotator the camera can turn without the focuser turning, so you can set the whole lot forward on the mount, as here;