Counterweights for a dob?

[wulfrunian]

Managed to get out for a quick session with the new goto dob on Sunday night - will post more in a review, but just one question first. It was fine apart from at low altitudes, then it struggled with the weight of the "nose" and kept dipping. I assume I need some sort of counterweight - what do people use on a dob, and would it affect its performance when it's pointing higher up?

[brantuk]

Have a look at the "Dob Mods" thread in "Dob Users Group" (click the link below) Loads of ideas for counterbalancing large ep's, cameras, etc

[haitch]

Hi Wulf,

Look forward to seeing the goto dob in action sometime soon.

I find the best place to weight a Dob so that it doesn't over compensate at higher altitudes is slap bang in the centre back of the mirror.

Of course mine has a thick piece of ply so I could screw a magnetic knife holder from Ikea ( IKEA | Wall & workspace organisers | Rails & wall storage | BYGEL | Magnetic knife rack ) to attach weights it's strong enough to hold an old counterweight off an EQ3.

[wulfrunian]

Thanks for the suggestions. Is there anything nice and simple for someone who's basically completely hopeless at DIY? Anything that involves drilling the tube is far too scary... I'm just proud that I've managed to unscrew a focuser and replace it with another in the same screw holes! Any way I can attach weights to the back of the mirror without risking wrecking the scope?

[insomnia]

Only yesterday I ordered a 10cm diameter magnet to stick to my 250 dob. I got my dob second hand and the previous owner had upgraded the focuser to a dual speed, and now its top heavy, plus when I put the break on it still slips down a fraction, enough to lose the object that I am looking at.

I have just ordered a wixey and am attaching a holder for my Android phone to my dob as well (trying Google sky as a poor mans push to)

[wulfrunian]

Yes I've got a dual speed on it too, plus I use heavy eyepieces. The scope itself isn't magnetic though is it? - I'm being really ignorant here aren't I!

[insomnia]

Magnets should stick to a dob tube, I tested some fridge magnets on mine and they stuck without any issue. Using a big magnet as a counter weight should be a very quick, cheap and accurate solution.

[wulfrunian]

Thanks, I'll test some out on mine, sounds good

edit - where did you order a magnet that size from??

[m.tweedy]

I use some 2 inch squares of mild steel painted with hammorite and heavy duty velcrose (hook side) and have a strip of heavy duty velcrose (loop side) across the bottom of the dob and depending on the weight of the eyepieces attach as many weights to the bottom of the dob as needed. it works but does not involve any drilling or anything of a permanent nature.

[insomnia]

I got this magnet from e-Magnets UK - Specialist Supplier of Neodymium Magnets, Rare Earth Magnets & Permanent Magnets

Lots of fairly cheap magnets on their site.

[Moonshane]

my tubes are both aluminium.

bot sure about SW though.

I have done this in two ways. I recently bought a used set of tube rings and they work a treat.

another is http://stargazerslounge.com/diy-astronomer/109577-latest-dob-mods-fan-balancing-weight.html

yet another option is car wheel balancing weights which are self adhesive and can be stuck inside the bottom of the tube?

[wulfrunian]

Lots of great ideas there, thanks v much folks

[Aussie Observer]

I have attached some large fishing sinkers to the end of the tube with tape which works very well.