First Light - at last - 16" Lightbridge (LB)

[johninderby]

If you want to make your own counterweight setup for the LB16 it's quite easy to do and not too expensive.

Takes three each of Counterweights, Tommy Nuts and M12 bolts

Unscrew the three plastic feet from the bottom of the scope and drill out the holes to 12mm. There's plenty of room to do this without removing the mirror. Just stuff the gap between the tube and mirror with cloths of some sort and then use masking tape to seal the gap between the mirror and tube wall. Do however protect the back of the mirror with a small piece of plywood when you drill the hole just in case.

There is enough room to insert the bolts with one washer from the back. Put several of the large washers on the top side so that the counterweight clears the rim. Add the counterbalance weights and the Tommy Nuts and tighten and that's it. I recommend adding some 25mm diameter felt pads to the Tommy nuts as this cushions the shock when you set the tube down on the ground.

You may need a bit of extra weight. I used a 1kg Go Cart lead weight. You can just see the edge of it poking out from under the bottom rim near one of the counterweights. I cut a notch to fit around the bolt head of the counterweight bolt and attached it with Velcro.

Parts needed

From Telescope House: - Counterbalance Weight 13mm Bore

http://www.telescopehouse.com/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fwww%2etelescopehouse%2ecom%2facatalog%2fTeleVue_Ethos___Zooms%2ehtml&WD=counterweight&PN=Counterbalance_Weight_13mm_Bore%2ehtml%23aBC055#aBC055

From WDS Ltd: - Tommy Nuts

http://www.wdsltd.co.uk/Fixings,%20Torque%20Screws%20&%20Knobs/Nuts/WDS613%20Tommy%20Nut

M12 stainless hexagon head bolts (50mm I think) and 12mm "body repair" or large diameter washers

Felt Pads (Focus DIY etc.)

John

[albedo0.39]

Hi Doc - when taken, indeed the RDF was missing along with the EP. I'm not planning to add any other finder except for the laser (which of course I will not use except on very rare occiasions and NOT at star parties) but that's it @ the U OTA.

It's fair to say that my First Light was hurried and I have no frame of reference for what this mythical "buttery" movement feels like, but I can report a high degree of static friction (stiction) in both bearings.

Anyhow.. .early days. I'm learning so this is all good stuff.

And as for the comment on the T shirt - I agree... It was FREEZIN' at the time but I just grabbed something with no sense of fashion. I will try harder for the next observing session