Care to see an unusual mount?

[bluegoatwoods]

Here it is.

This is really just a proof-of-concept model using a telescope that'll never see much actual use due to it's small aperture. But it's working well enough that I have confidence that the final version will be good. That one will have either a 114/500 mm reflector or a 102/900 mm reflector.

I'll need to make the final version just a bit more stout, I think, because I can see a bit of sagging on this one from some angles.

The base is a Dobsonian mount from a $100 telescope, merely extended up a bit. The bicycle wheel axle provides the telescope up/down axis of rotation. Grabbing and holding the wheel is how I aim the scope up and down. Smooth and easy to control.  This particular wheel has a hub brake. It's not too clear in the photo, but the lever is mounted to a sawn-off handlebar and the whole thing dangles on the cable. It's a simple matter to hold it in either hand and adjust the scope up/down and left/right holding onto the wheel rim. When I reach the height I want a squeeze of the lever holds the scope dead still.

Note also that the eyepiece is mounted very near the axis of rotation. So the eyepiece remains at very nearly the same level from the ground whether the scope is aimed at the horizon or at the zenith.

This particular bicycle wheel was not inexpensive, actually. But that doesn't matter since the same thing could be done with a wheel rescued from the garbage. One would also then need to mount a rim brake. Right there on the Dobsonian base would work just fine.

 

[saac]

Any backlash  

JIm 

[bluegoatwoods]

When there are no counter-weights, yes, the backlash is pretty bad. Right now there's 4 lb (!) of counter-weight. But there's no backlash.

Even in the final version I expect to need some counter-weight. But I hope to minimize it with careful mounting. I'll even be willing to trade off some eyepiece height variation, to a small degree anyway, in order to keep total counter-weight low.

[Pig]

I guess it will be good for viewing the Pinwheel Galaxy

[AngryDonkey]

? This is the coolest thing I've seen on this site for a long time (maybe with the exception of that insane M31 image that has recently resurfaced, that is just beyond good)! I'm very much looking forward to v2!

[iPeace]

That is absolutely brilliant.

1 hour ago, bluegoatwoods said:

the eyepiece remains at very nearly the same level from the ground whether the scope is aimed at the horizon or at the zenith. 

Genius.

[bottletopburly]

That looks crate , can’t see it wheelie catching on , ???

[Demonperformer]

The ingenuity of members on SGL never ceases to amaze me. Good luck for the final version.

[bluegoatwoods]

3 hours ago, bottletopburly said:

That looks crate , can’t see it wheelie catching on , ???

Hmm.......not bad.

One reason I've been modifying mounts is that I don't like my telescope jumping around like a rabid hare when I'm trying to zero in on something.

Now you've put in my mind a picture of my scope layin' a patch and making a run for it.

[Carbon Brush]

That is a great idea. It has all the elements of well built kit using standard mass produced (= low cost) parts.

Wonderful idea to keep the eyepiece near the centre of rotation.

All the best for the  Mk2 version. Keep us posted.