Part-work Orrery

A place to hang out and chat about astronomy

RE: Part-work Orrery

Postby les » Tue May 26, 2009 1:46 am

HI Gavin,
Ive found small adjustment here and there do solve any running problems Ive had,not that Ive had any for weeks now.[:)]My Earth orbit period is about 45-48 seconds so a bit slower than yours.Some tinkering would maybe speed things up a bit but since its running smoothly I think I'll leave well alone(if its not bust dont try to fix it).
Regards and clear skies Les.
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RE: Part-work Orrery

Postby clipperride » Sat May 30, 2009 1:36 am

[quote]ORIGINAL: smeagol

One thing I can't remember seeing mentioned is positioning the central rod, that the sun is fixed to, and tube, that all the gears are fixed to.

My Orrery started to run noisily after assembly and after some fettling I realised that when I assembled it I had positioned the central tube as far into the base as possible.  This meant that the central rod was putting all it's weight onto the output gear, as the motor gears run in, effectively, plain plastic bearings I felt that this would be likely to reduce the life of the gears considerably.  To combat this I raised the central tube slightly to ensure that it's weight was not resting on the output shaft and that the weight of the sun was not resting on the output gear of the motor assembly.

Since doing this the noise level has reduced considerably and I can achieve a 36.5 second orbit for the Earth.

Hope this is of use.

Smoke me a kipper, I'll be back for breakfast.


As far as I remember from the instructions.... The central support rod is supposed to fit so that it is flush with the underside of the engraved base plate. Glad to hear that others seem to have things running smoothly now. Mine has run for several thousand Earth "years" now and is still nice and quiet.


Mark B.
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RE: Part-work Orrery

Postby ghsat » Thu Jul 09, 2009 11:53 am

Hello to all, I am new in this world of the orreries and want to know if someone of you can raise the planes of assembly of the orrery.

I want to make an orrery and do not have ningun plane.

Thank you
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RE: Part-work Orrery

Postby makka » Tue Oct 27, 2009 4:06 am

have finished building orrery, had to replace 3 planet collars as couldn't tighten planet arms on Mars, Saturn & Pluto.
Decided to take apart and make sure all was tight and now runs smoothly.
Decided to remove gear that spins Earth/Moon around as this was jerky, even with the replacement gear.
Have question re engraved base plate.
If the planets are marked as per 24 August 2006, why is the Earth Symbol on other side (approx 19 Feb)?
And why put Moon symbol on ther side to where the Earth is?
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Re: Part-work Orrery

Postby Bread » Mon Sep 07, 2015 12:25 pm

Hi all.....

Anyone still active on this thread???
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Re: Part-work Orrery

Postby minimoa69 » Tue Sep 08, 2015 8:18 am

I have to admit that I was wandering myself if anybody here was going to take up the challenge this time around.
I will watch with interest!
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Re: Part-work Orrery

Postby Bread » Tue Sep 08, 2015 9:07 am

I'm certainly going to give it a try. Just got first 3 issues. Today I might try and print out the comments in this thread as it will surely help me to avoid / overcome some of the problems people had last time around.

If this thread gets enough interest this time, I might publish a build diary so everyone else can see just how bad a builder I am !!!
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Re: Part-work Orrery

Postby jsc248 » Wed Sep 16, 2015 11:53 am

Hi Gang,
# I have started getting this magazine by post direct from the team. It is going well at the minute and I am impressed with the orrery right now. I will post images as it progresses further and will let you know if any problems occur!

To me astronomy is looking up and thinking "What the heck is going on up there!!"
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Re: Part-work Orrery

Postby Bread » Sun Sep 20, 2015 8:23 am

Hi John
I was beginning to think I was the only one doing the orrery this time!! I'll also post some pictures, but mine might take a little longer as I intend to electro-plate mine in gold, and you can't plate directly onto brass - you have to give the parts a base coat of white bronze first.

The only problem I've had so far is putting the issues in the binder. There just has to be a better way.....

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Hello, and answers to Mike’s questions

Postby Peter Ells » Sat Sep 26, 2015 9:38 pm

I’m also building the orrery, and have reached Venus so far. In this post I’m going to answer a couple of questions that makka (Mike) posted on Tue Oct 27, 2009 (This is quite a recent post in the thread, despite the date). Mike asks:

“If the planets are marked as per 24 August 2006, why is the Earth Symbol on other side (approx 19 Feb)?”

This is because (as is standard for orreries) the position given is the apparent place of the Sun in the heavens as seen from Earth. It is more easily seen on the top, engraved gear. See page 9 of issue 1 of the magazine, which shows both the Top Gear and the Base Plate, in identical orientations. The First Point of Aries is depicted at the top of the Base Plate and, corresponding to this, 0 degrees ecliptic longitude is depicted at the top of the Top Gear. (Ecliptic longitude is marked from 0 to 360 degrees around the circumference of this gear.)

Incidentally, the orrery should be assembled so that these disks line up as shown in these Figures: on the orrery, 0 degrees ecliptic longitude should be vertically above the First Point of Aries.

On 24 August 2006, the Top Gear shows that, as seen from Earth, the ecliptic longitude of the Sun is 330-180 = 150 degrees. Instead of ecliptic longitude, the ancient Greeks used Zodiac Signs. The Base Plate shows that the Sun is just on the boundary between LEO and VIRGO.

The Calibration Ring shows that, because of precession, ecliptic longitude 150 degrees is actually now within the constellation of Leo.

“And why put Moon symbol on other side to where the Earth is?”

The general rule is that the direction of the Moon as seen from the Earth should be made the same as the direction of the inscribed Moon as seen from the Sun.

Following this rule in the case of 24 August 2006, we see that the Moon should be turned so that it lies directly between the Earth and the Sun. I.e. the date in question is a new Moon, as may be confirmed at: ... d-position

The diagram “How to set up your orrery”, on pages 4, 5 of issue 4 of the magazine, shows how the above rule is applied when setting the orrery up for 7 BC.

I hope that this over-long post is helpful,
(Issue numbers and pages refer to the latest edition of the magazine.)
Peter Ells
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