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The Piston AZ mount

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#1 Tavi

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Posted 31 July 2010 - 03:33 PM

You can sometimes got a bright ideea right from the trash. An old engine piston, reversed, can become a great alt-azimouth mount for medium instruments like my 80x900 Fraunhofer refractor or the MTO11-CA 10x1000 maksutov teleobjective used as a small visual scope. The base is a 80x4mm textolit disk with a 10mm hole in the center and a 8 mm half-hole at the edge to prevent rotation on the tripod head, where is a cilindric head screw. The azimouth bearing are 3 teflon pads 20x8x2.5mm at 120 degree near the edge of the piston head, mounted with 3 M3 screws. A M10 screw and nuts&washers form the vertical axe:

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The altitude bearing is the original bolt of the piston. The axe is a long 12 mm screw, assembled with nuts&washers. I will make an orizontal plate fixed with 2 screws instead the ones with plastic heads and a tension teflon pad, pressed with one screw, to control the altitude smooth moving and fix in the position. The instrument is fastened to the axe with a galvanised steel plate (standard for wood buildings) and some nuts and washers.

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Except the teflon pads, all nuts&bolts are cheap and easy to find at local store, you need only hand tools to build this simple mount. You can put 2 instruments in parallel, replacing the counterweight with another plate.

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#2 neo

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Posted 31 July 2010 - 05:14 PM

Great job Tavi! :applause: :applause:
I guess many of the great ideas don't come in front of the CNC machine :lol:

I believe it's much more sturdy then your first version, the pipe mount.
It's just me or it resemble with a Giro mount?

#3 Tavi

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Posted 31 July 2010 - 06:18 PM

Indeed, is more sturdy and smooth than the pipe mount. And is easier to built, no machined pieces, the textolit base was cut with a small handsaw and rounded with a corner grinder. The total time of build, except planning and thinking is roughly 3 hours.

Of course, it resemble a Giro mount, not so beautiful... :) I wonder to keep or not the black burned oil coating? :rollgrin:

#4 Sean Cunneen

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Posted 01 August 2010 - 12:08 PM

That is great! I'll bet it took some time to get the rings to seat...

#5 Tavi

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Posted 01 August 2010 - 03:47 PM

Thanks, Sean!
I kept the rings on as it was get from the engine, maybe that car has travel more than 4-5 Equators... :)

#6 Ed Holland

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Posted 02 August 2010 - 04:13 PM

I like that - very clever Tavi!

One of my telescopes has a cam sprocket counterweight. Maybe should start a car parts astronomy thread called, perhaps... Auto-star?

#7 Tavi

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Posted 02 August 2010 - 04:41 PM

Thanks, Ed!
A car has a lot of useful parts, but be aware: do not disassemble your own! :bow: :D

#8 Ed D

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Posted 02 August 2010 - 06:07 PM

Just when I thought I was getting old and had seen everything!!! That is a nice mount that shows a lot of imagination and skill. Very good way to recycle old aluminum.

Ed D

#9 neo

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Posted 03 August 2010 - 02:04 AM

I like that - very clever Tavi!
Maybe should start a car parts astronomy thread called, perhaps... Auto-star?


Car tuning&telescopes :lol:

#10 Hitech

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Posted 03 August 2010 - 01:19 PM

Make your next OTA from 4" diesel exhaust pipe with muffler clamps to the mounting plate.

#11 StarStuff1

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Posted 03 August 2010 - 05:51 PM

If you move it too fast in any direction does it give off a little blue smoke? :lol:

Seriously, a clever and innovative idea.

Perhaps you should also post this in the Frugal Astronomer thread in the Beginners Forum.

#12 Scopyfrank

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Posted 04 August 2010 - 08:48 AM

Brilliant.
:bow:

#13 Tavi

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Posted 04 August 2010 - 05:42 PM

Thank you, friends!
I hope I could test it live soon! :)

#14 eric_zeiner

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Posted 04 August 2010 - 07:54 PM

That awesome :bow: :bow: :bow: :bow: :bow:

#15 Tavi

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Posted 15 August 2010 - 03:41 AM

At the first session of observing with the new mount, it work smoothly on the both axis, easy to find objects on the sky and easy to fix in position. The only trouble is, for the moment, to put the OTA in equilibrium at first. The mount need a better fixing system on the altitude bearing.

#16 Tavi

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Posted 22 August 2010 - 08:17 AM

The new configuration with 2 telescopes:

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In the left is my homemade Fraunhofer 80 F/11.25 refractor and in the right side is the MTO11-CA russian teleobjective modified as a visual maksutov telescope.

The mount work great, easy to position on the sky, the only problem is vibration, the orizontal axe is to thin.

Yes, the white dot near the Hyperion eyepiece is Lady Moon! :)

#17 Tavi

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Posted 29 August 2010 - 03:07 PM

After a friend gave me two sets of tractor pistons and some time spent thinking and machining at a friend's workshop some parts, I'm building a bigger one:

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This mount is more expensive than first, I had to design and made special parts: the axis, bushings, fine aligning systems... which I'm working these days. I want to use nut-screw mechanisms at both axis for this mount, cause I have no worm gears available.

It will looks like this:

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The diameter of the tractor piston is 110mm, the orizontal axe is 32mm dia. by 300mm long. This mount will support two heavier instruments, maybe one of them will be a 200mm cassegrain which I want to build nextyear...

#18 neo

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Posted 30 August 2010 - 03:08 AM

Hi Tavi,

That's awsome! :applause:

For such a serious mount it would really be nice to fit worm gears on both axis and steppers connected to a computer and voila...go to mount :)
Some nice worm gears could be cut on lathe with a standard tap. Although it's not a by the book method to cut worms gears, many amateurs got very good results with a bit of patience and practice.

Check this out http://www.atmsite.o...r/wormgear.html

#19 Tavi

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Posted 30 August 2010 - 03:30 AM

Thanks, neo. But I don't think that my craftsman can do the job, I had spoked with him earlier about worm gears, so I'm looking for some professional gears to buy, for the third mount, wich will be a german equatorial. This alt-az is experimental, I try to figure out what are the best solutions to use the already shape of the pistons. For example, the EQ will have a fixed pipe instead, mounted in another piston as a declination axe. The second piston will form the declination support, using rolerbearing instead bushings. The head to telescope dovetail bar will be the actual base of the AZ, and the actual vertical axe will be the right ascension one. :)

#20 mattyfatz

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Posted 30 August 2010 - 02:55 PM

Genius

#21 Tavi

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Posted 29 September 2010 - 03:34 PM

Some ehnancement of the homemade tripod:

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- internal alu arms for increased rigidity
- accessories triangle dish
- aluminium conical shoes, replacing the rubber ones
- carry belt, cause the tripod is very heavy... :)

#22 neo

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Posted 29 September 2010 - 04:26 PM

Tavi

Congrats and well done :waytogo: :waytogo:
Absolutely brilliant!

#23 Tavi

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Posted 22 April 2011 - 05:32 AM

The AZ-piston mount nr.2 is almost complete, ready for testing at night!

Here are azimouth fine tune mechanism:
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It's based on a stainless steel M6 long screw:
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The Fraunhofer refractor (80F/11.25) and the maksutov-cassegrain teleobjective MTO11-CA (100F/10) on the mount:

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The stability of the mount is impressive and the fine tuning, can be improved, but useful. I will test the mount in the following spring hollydays.

#24 eric_zeiner

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Posted 22 April 2011 - 04:38 PM

Now you are cooking! :bow: :bow: :bow:

#25 neo

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Posted 23 April 2011 - 07:02 AM

Fantastic job Tavi! :waytogo: :bow: :bow:
I imagine that a drive system (maybe even Goto) would be a terrific addition to this mount. The only problem would be finding a good 'n cheap set of worm gears but with some patience... :smirk:






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