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Equipment Discussions >> Observatories

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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: Ecurb]
      #4777963 - 08/30/11 12:13 PM

Quote:

Rob,

Can't you just gear-up the motor? Put a larger sprocket on the motor and a smaller one on the "drum drive". Many AC motors are reversible, although if the name plate says it isn't, it probably isn't. Another option would be to go for a DC motor. They are almost always easily reversible. And surplus ones are cheap. Like from an electric "ride on" child's toy or a scooter. Check out "Good Will", etc., for one with broken wheels, body, frame, but a good motor.

Bruce




Bruce..I have a 12v motor from a bike and it is 2237rpm reversible but requires 15.3amps. What kind of power source can I use to run it? A battery?

What would be excellent..is if I can control the speed of the motor too...the DC motor is great for this...I just need a controller to do so.

Rob


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Ecurb
member


Reged: 05/16/08

Loc: Kirkwood, California
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4779256 - 08/31/11 12:13 AM

Hi Rob,

Did the bike have a speed control? If not, they are easy to get, but do cost money. A good efficient one with 25 Amp capacity and electronic reversing, will cost $75 new. We use them in our electric powered, large scale (7 1/2 inch gauge track, 1/8 to 1/4 scale size), ride on railroad trains. Also check e-Bay. Search "Electric Scooter Parts". I know you do not want to spend extra money, so another (inefficient) way is to use series resistance to lower the voltage. Big power resistors, or even light bulbs, would work. It would be trial and error to find what would work best. You can reverse a DC motor by reversing the power leads with a DPDT (Double Pole, Double Throw) switch. It would need to be able to handle the current. Because of the low voltage, an old open frame DPDT knife switch would work. The advantage of a good electronic speed control is that you can get near full power at low speed. Another source of DC motors is a used (or new) electric wheel chair motor. These have built-in gear reduction. A battery would work for power. Or a "basic" battery charger with enough capacity. It would need to be a "basic" model. Most of the good electronic ones will not turn on unless they first sense that a minimum amount of voltage is present.

Bruce


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: Ecurb]
      #4779816 - 08/31/11 10:46 AM

Quote:

Hi Rob,

Did the bike have a speed control? If not, they are easy to get, but do cost money. A good efficient one with 25 Amp capacity and electronic reversing, will cost $75 new. We use them in our electric powered, large scale (7 1/2 inch gauge track, 1/8 to 1/4 scale size), ride on railroad trains. Also check e-Bay. Search "Electric Scooter Parts". I know you do not want to spend extra money, so another (inefficient) way is to use series resistance to lower the voltage. Big power resistors, or even light bulbs, would work. It would be trial and error to find what would work best. You can reverse a DC motor by reversing the power leads with a DPDT (Double Pole, Double Throw) switch. It would need to be able to handle the current. Because of the low voltage, an old open frame DPDT knife switch would work. The advantage of a good electronic speed control is that you can get near full power at low speed. Another source of DC motors is a used (or new) electric wheel chair motor. These have built-in gear reduction. A battery would work for power. Or a "basic" battery charger with enough capacity. It would need to be a "basic" model. Most of the good electronic ones will not turn on unless they first sense that a minimum amount of voltage is present.

Bruce




I use DPDT swithes all the time for reversing motors...but I am looking for a power source to run the 12vdc motor that provides at least 15amps. Where can one get one of these?

All the ones I have ever used are for model trains and they do not provide enough amps.

Rob


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Ecurb
member


Reged: 05/16/08

Loc: Kirkwood, California
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4781379 - 09/01/11 12:23 AM

Hi Rob,
For power, some options are:
1) Use a car battery (a Deep-cycle type would be better). You can justify this as being your emergency jump-start battery for any vehicles at your place. Add a small trickle charger. Get a good one, like a Deltran, so it doesn't kill the battery if left permanently connected.
2) Use a "basic" battery charger with enough capacity. Remember that it needs to be a "basic" one. No fancy automatic stuff.
3) Buy a 12 volt power supply. Check e-Bay. Search for "12 volt power supply". Motors are hard on power supplies. I would get at least a 30 amp. I saw a new one for $26 (12 volt DC, 30 amp, 115 volt AC input). Look for used equipment. It does not need to have great regulation or filtering. Just a basic power supply.
4) Build your own. All you need is a transformer and a rectifier. A) Search e-Bay for "Bridge rectifier". Get a 30 amp (or more) with a 50 volt (or more) rating. Bolting it to a piece of metal would be sufficient for a heat sink as you are only using it intermittently. If it gets too hot to touch, you need a bigger heat sink. B) Search e-Bay for "12 volt transformer". I would look for a 20 amp. You should also add a fuse on both the primary side (115 volt) and secondary (12 volt). Use an "automobile" style fuse for the 12 volt.
5) Go back to the "ship's wheel", and have your visitors supply the power to open her up. I would gladly do a little work for the opportunity of having great views.

Bruce


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: Ecurb]
      #4840048 - 10/02/11 07:23 PM Attachment (42 downloads)

OK..some time has elapsed while I got my act together concerning the drive system for the ROR. I tried 2 single phase single direction motors with belt drives.

That flunked due to sever slipage.
I ten came across a chain drive off an old electric bike my daughter had.

Problem ramained about the motor.....

I found a 110v motor with a 2.5rpm gear head and i built it in to the chain drive. Problem...it only drives in one direction..meaning I can only open the roof.....

What to do...what to do...

It dawned on me. I will connect another motor to the exiting drive shaft of the main motor via drive gears. In this way the main motor runs while free wheeling the second motor. when the roof is out and stopped...Then I turn on the second motor and it will run at 13,000rpm driving though the now free wheeling main motor(in reverse)...closing the roof.

So that is what I did....I used motors I had in the shop and all the gears too. Of course it required lots of lathe time and maching to make work.

So here is a pic of the finished drive system.....note the smaller 13,000rpm motor afixed to the main motor.

Rob


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4840056 - 10/02/11 07:26 PM Attachment (34 downloads)

From the other side..note the gear drive connecting the motors...and the spring loaded roller to keep the slack side taaught against the drive sprocket.

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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4840066 - 10/02/11 07:32 PM Attachment (33 downloads)

Here is one across the room..showing the entire motor..drive shafts and cable drums for the system.

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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4840073 - 10/02/11 07:38 PM Attachment (30 downloads)

And one more from the other side of the pier.

Rob


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4840092 - 10/02/11 07:48 PM

In conclusion...I was able to use a $10 gear head motor I got at the wrecking yard.....pipe I had...and another high speed motor..along with all the hardware(I had)...I built a nice opening and closing system for the roof.

If the sistuation ever arrises..I might replace the motor with a 1300 lb winch refersible winch motor...that I modify with a sprocket. Till then..these 2 motors in conjunction, do the job nicely. The entire system cost me $40 maybe.

Rob


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mikey cee
Postmaster
*****

Reged: 01/18/07

Loc: bellevue ne.
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4840182 - 10/02/11 08:41 PM

No wonder you are a good denturist! You actually think outside the box. Mike

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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: mikey cee]
      #4840260 - 10/02/11 09:22 PM

Quote:

No wonder you are a good denturist! You actually think outside the box. Mike




One thing is the main motor runs clockwise..but the gear head runs counter clockwise...I then took the second 13,000rpd motor which also runs clockwise..and engaged its drive gear to the gear I put on the extended shaft of the main motor on the side to drive the main motor counterclockwise...hense..now driving the chain sprocket in reverse...... Heehee......

I also ran wall 110v wire from the red light switch by the door around the wall to another switch box that has 2 switches to controll a power strip and to directly control the on/off of the main motor. I also have introduced a speed control for the 13,000rpd motor so I can slow it down as the roof reaches it end.

Out of the box Rob.....


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4841539 - 10/03/11 02:28 PM Attachment (33 downloads)

Here is a closeup of the drum/cable/pully system for each end. See how the inner drums cable runs on the outside..up to the pully and back toward the other side to open the roof...and the outer drums cable runs the opposite direction on the inside up to a pully mounted on the corner brace to an *EYE* bolt bolted to the West wall for closing the roof. Steel corner braces were added for strength

It works great and effortless.

Rob


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #4841561 - 10/03/11 02:40 PM

One note to reader. The standard 1" plumbing pipe is not the same as the standard garage door 1" pipe. I had to put each drum in the lathe and turn the center hole open to recieve the larger plumbing pipe. I also used plumbing flanges as end bearings...so they too needed to be turned(removing their threads) to open them up to recieve the pipe. I drilled large holes into the suport 4x6 beam to allow the pipe to slide in to permit assembly then slightly pull back out when assembled. 3 flanges were used as bearings. One for each side and one in the middle to support the junction point of 2 pipes. All in all it was a fun project and more then that it was made with materials on hand.

Rob


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #5226049 - 05/16/12 11:35 PM Attachment (28 downloads)

Nice evening so I opened up the roof...here is an image from the outside Westside. Roof is half open. It's amazing how big that roof is when run out all the way.

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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #5226054 - 05/16/12 11:42 PM Attachment (29 downloads)

Oh and one from inside as the roof was moving off over the scope. I love watching the roof roll off by itself.....

Motorizing the roof was one of the best mods I did to the OB.

Rob


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #5248048 - 05/30/12 09:41 PM

I was able to be available to show a large group of people(Over the long weekend) who had never looked through a telescope before...some great times at my Observing Center and specifically through my large refractor. Nothing lifts my heart more when it comes to my hobby..when I can lead folks to the wonders of the heavens, who have never looked through a telescope before. Fun times and fantastic emotions to see the faces of people seeing Saturn or the moon for the first time.

The crowd was simply amazed to see a telescope someone made themselves..and to look through several other scopes as well.

Having a large Observatory(any observatory for that matter) really sets the stage for education and promotion for astronomy and related hobbies.

What a great time...

Rob


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Ecurb
member


Reged: 05/16/08

Loc: Kirkwood, California
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #5248368 - 05/31/12 04:34 AM

Hi Rob,

Now that the motorized roll-off roof is all working, did you find a new use for the ships wheel? I always thought that was a neat addition to the observatory. You really should have it do something, like: raise a flag up the flag pole, ring a bell (ring when somebody at the eyepiece says "ahhhh, wow"), move a sun shade for daytime open-roof use, etc.

Bruce


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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: Ecurb]
      #5248830 - 05/31/12 12:53 PM

Quote:

Hi Rob,

Now that the motorized roll-off roof is all working, did you find a new use for the ships wheel? I always thought that was a neat addition to the observatory. You really should have it do something, like: raise a flag up the flag pole, ring a bell (ring when somebody at the eyepiece says "ahhhh, wow"), move a sun shade for daytime open-roof use, etc.

Bruce




Hmm...I haven't given it much thought as of late..but I should. You bring up some good ideas.

My OB is generally pretty basic...no carpet..no sheet rock..no warm room(it doesn't get that cold enough here for one of those)...just bear wood...that is one reason I like the ship theme...and it goes so well.

I loved the shipwheel when I used it..I just love sitting back and watching the roof run out all on its own now...and I can monitor things better now as well as the roof runs out. I have a pretty tight fit with the counterweights being only inches from the rafters as well as the 5" spotter on one end and the objective flange on the other end. It's pleanty of room but from the ground it doesn't look like it...oh probably about 2.5" of clearance on all 3 spots. So you can see why I wanted to make the electric drive change.....

I'll do something with the ship wheel...it still matches the decor..so its cool( but a function would be cooler)

Thanks for reminding me and giving me suggestions.

Rob


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opticsguy
sage


Reged: 02/02/09

Loc: Washington State
Re: Gold Mtn Observatory new [Re: rwiederrich]
      #5551830 - 12/03/12 10:58 AM

hello, trying to work my way through all these postings!!! Great job on your OB and scope. I am in the exact place you were when you started, a scope and no observatory. So, now in the initial thinking/design stage. My observatory would measure 20x20 with 10' walls with ROR. What did you use to design your trusses? Off the shelf or engineered or?

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rwiederrich
Goldfinger
*****

Reged: 11/17/05

Loc: Always Dark skies of Belfair W...
Re: Gold Mtn Observatory new [Re: opticsguy]
      #5552317 - 12/03/12 03:50 PM

Quote:

hello, trying to work my way through all these postings!!! Great job on your OB and scope. I am in the exact place you were when you started, a scope and no observatory. So, now in the initial thinking/design stage. My observatory would measure 20x20 with 10' walls with ROR. What did you use to design your trusses? Off the shelf or engineered or?




Welcome Opticsguy.

First. I thought it out real long and wanted to save loads of money and wanted to do it myself(to do so)....As you noticed my pier is 8ft tall so the 8ft tall walls. I also needed to use dimentional lumber..so I didn't want lots of extra material I had to cut off..as you know 4x8 sheets of siding can be cut to fit an 18ft building exactly...with no left overs. Same with the studs. What I did was call a local truss engineer and had him email me the exact schematical drawings for the trusses I wanted...then I simply built them off his drawings. I didn't use the steal presses for the joints(same money) so I cut and nailed on all the joint bracing. Because the building was tall and I had a central pier to use as a scafolding base, I built my truses in place(again to save on the delivery fee)...and since my trusses are built in place, I could use a ridge cap...cuz I alwa wanted to avoid plywood sheath and 3 tab roofing(save more money and weight).

I can help you with any designs or ideas if they are found to be acceptable, just let me know.

Good luck in your design and build.

Rob


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