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Suggestions for Counterbalance weight on 12" Flextube?


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Hi Guys

With the finderscope,Telrad inc 4" riser and homehade dew shield on the end of the OTA i am finding that when the scope is at a low altitude it is difficult to stop it slowly dropping even with the altitude tensioning screw handle pretty tight.

Has anyone got any ideas as to a quick method of adding weight to the opposite end of the OTA to try to balance the arrangement?

thanks

Graham

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I will be adopting the same design as i used for my Revelation 12. I'm not worried about taking a drill to my kit, so will be adding a dovetail to the back end of the tube, with an EQ6 puck and weight running on it. Worked a dream last time.

Although this time i am considering adding the dovetail on the underside at the opposite point to all the weight at the front. It will restrict views to the zenith but dobs are a pain that far up anyway, so no loss.

post-12650-133877607877_thumb.jpg

Edited by russ
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I think part of the problem with the flextubes is the small radius of the alt bearing. if you could find a way to increase this then it would make for easier balancing I suspect. I have seen others make new bases for these excellent scopes from plywood.

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...and astroboot has some small counterweights AstroBoot

Helen

I was going to suggest these but the bore hole are between 10-11 mm and the retaining bolt on the magnet is 6mm I don't suppose it would cause any real problem if you have a large washer and tighten the nut down tight. I decided on a modification which also allowed for more weights to be fitted http://stargazerslounge.com/diy-astronomer/142460-my-go-dob-balancing.html

I think Shane has made a good point about the rocker box as I have seen a trend towards flexi tube owners suffering balancing problems more so than solid tube owners.

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I have seen a trend towards flexi tube owners suffering balancing problems more so than solid tube owners.

It's a very real problem. I was quite surprised when i first tried the Flextube just how poorly judged the balance point has been set. And you really don't want to be using the friction brake to overcome poor balance if you can help it.

There's also a design flaw with the flextube poles. If you carry the scope with the tube collapsed and the single pole towards your body, you end up denting the main tube.

Plus the silly rubber stoppers, that prevent the upper and lower tubes touching, creates a huge gap for dust to ingress.

And the Azimuth motion (in common with all the Skywatcher dobs i've owned) is pretty darn awful.

Hmm that makes it sounds a pretty crummy scope but i do like it.

Edited by russ
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Take a look in the Dob Users social group (click link in my signature). There's a thread in there called "Dob Mods" - lots of interesting solutions to dob balancing in there :)

Edited by brantuk
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