battery-free focuser!

[beamish]

Well it looks like the cloud gods are beginning to close in for tonight.

However on the plus side,I can certainly recommend the battery-free focuser. It worked a treat last night, happily lifting the 30mm with no slippage, the little cradle to sit the servo at the crayford end I made from some Al sheet from Maplins, as a simple three-sided box, with one side slightly curved to accommodate the curve of the OTA. The whole thing is then simply stuck onto the tube using dbl-sided sticky pads.The servos were bought from a good model shop. I modified the plan a little by adding a clip in the wiring so that I could then detach the operator end when tidying up for the night.Great !! For the wheel that actually engages with the crayford I used a couple of self-adhesive rubber feet (for laptops) from Maplins again. Bought a great gas powered solder kit too,(in the sale).

Needless to say I was actually v pleased on a no of fronts last nite (mind you should'nt use the word front really, given the clouds we've had the last month).

http://telescope.marford.me.uk/Projects/ElectricFocuser.htm

here's the page I used if you're interested.

Karlo

[geppetto]

Nice little project Karlo 8)

[beamish]

cheers Phil.

[zhgutas]

Very nice I would never thought of it 8)

[Boris6]

Thats a nice idea, all that servo spinin' may also keep you warm on a cold night.

[beamish]

Very nice I would never thought of it 8)

Thanks but I can't take any credit for it, someone else on the forum was talking about making one not too long ago and I was intrigued. I was frustrated at the price and relative inaccessibility of electric focusers, followed their link, followed up a few others in the chain(you know how it is), then chanced upon this link and thought "I could do that". So set to work, and lo it was done, I added a 1cm strip of self adhesive "non-slip" stair tread tape around the focuser wheel to get some purchase on the rubber "feet"(see above).

It was as simple as it looked! And NO JUDDER when focusing as clearly you don't touch the OTA. BL**DY MARVELOUS !!

the initial link used was

http://www.csastro.org/gallery/article2.htm

next was

http://telescope.marford.me.uk/Projects/ElectricFocuser.htm

Thats a nice idea, all that servo spinin' may also keep you warm on a cold night.

Well suprisingly I was quite impressed at how efficient the transfer of power was not much needed, the shot single malt kept me warm!

[Boris6]

....... I was quite impressed at how efficient the transfer of power was ....

well, that's rare earth magnets for you; it's really quite surprising what we couldn't do with out 'em!

[GordonCopestake]

Nice little project. Is it a 1:1 ratio when you turn the other motor/generator?

[beamish]

Nice little project. Is it a 1:1 ratio when you turn the other motor/generator?

No not quite Gordon but certainly close enough. Initially prior to adding the clip in the wiring the wire was perhaps 3-4 feet long, on shortening the wire I noticed a huge improvement in the efficiency /ratios. the final length is only1 1/2 feet long, enough to operate comfortably whilst looking thru the EP. I'm hoping it will be a help when using the Hartman mask too!

karlo