Helical focusers for Telescope making workshop

[Anil]

Hi all, i have designed these helical focusers for Telescope making workshop for ABAA (Association of Bangalore Amateur Astronomers.) This is a much better option over conventional cheap plastic focusers.

It has been designed from solid aluminium bars This design offers a fast & smooth helical movement, no slop, and backlash free performance, with 2 inch travel. Focusers are machined to very precise tolerances which is necessary to provide accurate alignment, each weighs around 550 grams.

[mental4astro]

Hi Anil,

Very nice looking collection of shiny new focusers! They certainly look robust. Any commercial outlook?

Are you maybe considering a 2" version?

How long is the draw-tube travel? Is the draw-tube longer than the focuser housing? This makes the travel capacity longer and more flexible for a range of applications.

I have one suggestion: maybe on the mounting surface of the focuser, either mill out a curved surface for better mounting to the scope, or mill out little 'legs'. These will allow for a more positive coupling to a round reflector tube. It may also help to further reduce weight, and doesn't compromise strength.

[Anil]

Thanks for the comment, yes i am thinking of marketing it here in India. Here a branded creyford focuser costs $150 but my helical is a better alternative to cheap plastic Rack & Pinion focuser. i certainly look in to 2" version on my next project with long sliding draw tube. The present version has 3" drawtube with 2 " travel. I shall also consider your advice on milling out a curved surface for better tube contact & final product will be black anodized.


Regards,
Anil

[mental4astro]

Just one note on the 2" version, stick with the helical design, not sliding.

I did not mean to confuse you. I really like helical focusers! I've used both 1.25" and a 2" version on a scope I've made.

[Anil]

2" version will be helical with long draw tube with 1.25 adapter. I shall share the picture soon.


Regards,
Anil