10” Equatorial Platform for Dummies

[AstralFields]

Also to come back to the printable segments shared in this thread. They are incorrect for all the latitudes. Seems like Reiner has counted with a tilt degree for the segments of 15 degrees but in the plans it is 20 degrees. For some of the latitudes he did not apply the segment tilt at all, making the error bigger.

In practical terms this will induce some errors necessitating to change the speed of the motor during the tracking and some minor drift.

After I fixed it for my latitude, the difference between 15 degree tilt or 20 degree tilt is obvious

Sorry for the bad news to everybody who printed the segments for their platform. On the bright side, I guess they can be easily replaced. I may create a fixed version after I finish my platform for all latitudes as it is pretty easy using Libre Office - Draw

 

Another mistake I have noticed in this thread, people have printed the segments at the wrong scale. Somebody asked about this and someone else took a picture of a ruler over the segment. When you open them in Libre - Draw using the in-app rulers for the page, it is clear how big they should be. One can even draw a simple line and see exactly to mm how long the segment should be.

This is likely induced by the incorrect handling of PDR printing by the printer and some auto-scaling stuff going on due to printer margins.

To avoid, it is best to import the plans in Libre Office - Draw. Fix the segments there and print the segment directly from the app.

In order to perform the fix, one may need to temporarily increase the page size to 100x100cm as the ellipse creating the segments is that big.

The exact dimensions of the segments are very important because the distance in the plans is fixed at 244mm between them (meaning they should be at a specific size). Again all of this can be verified in Draw.

Not having them exact is again inducing minor errors in the system.

Edited April 13 by AstralFields

[PeterStudz]

@AstralFields, interesting… thanks for this. Although after using my EQ platform extensively for almost about 19 months it’s more than accurate enough for me. Eg I can view targets like Mars at high magnification (x375 which is about as far as seeing & my 8” Dob will go), then pop inside for a short break, make a coffee, come back and Mars is still well within the FOV. I’ve even used it for simple imagining.

As you say, it’s easy to make new segments, but I don’t think it’s worth fiddling with… if it works don’t touch it!

Edited April 13 by PeterStudz

[AstralFields]

Yeah .. To put things into context, the errors I am speaking of are like 1 degree per hour of tracking.. pretty minor but worth sharing for any new buiders.

[PeterStudz]

12 minutes ago, AstralFields said:

Yeah .. To put things into context, the errors I am speaking of are like 1 degree per hour of tracking.. pretty minor but worth sharing for any new buiders.

This is true.

Might be worth pointing out but I think that there are other errors that are more significant than this. Although for practical visual purposes they probably don’t matter. 

Eg the EQ1/2 motor drive. I love its simplicity but its speed isn’t always constant - you can see this for yourself by placing a voltmeter over the motor terminals. I have one as a permanent fixture that I can switch on/off. For practical purposes it doesn’t matter but it will create drift. And some of these little cheap drives are better than others. Bit of pot luck there.

Balance... Recently I took my magnetic balance weight off the end of my Dob and placed it onto the ground board for convenience. This just happened to be directly opposite the drive segment. Although weighing just 600g this was enough to cause my platform to slip to such an extent that it was no longer working properly. It took me ages to work out what was going on! 

[westmarch]

On 13/04/2024 at 10:27, AstralFields said:

Also to come back to the printable segments shared in this thread. They are incorrect for all the latitudes. Seems like Reiner has counted with a tilt degree for the segments of 15 degrees but in the plans it is 20 degrees. For some of the latitudes he did not apply the segment tilt at all, making the error bigger.

In practical terms this will induce some errors necessitating to change the speed of the motor during the tracking and some minor drift.

After I fixed it for my latitude, the difference between 15 degree tilt or 20 degree tilt is obvious

Sorry for the bad news to everybody who printed the segments for their platform. On the bright side, I guess they can be easily replaced. I may create a fixed version after I finish my platform for all latitudes as it is pretty easy using Libre Office - Draw

 

Another mistake I have noticed in this thread, people have printed the segments at the wrong scale. Somebody asked about this and someone else took a picture of a ruler over the segment. When you open them in Libre - Draw using the in-app rulers for the page, it is clear how big they should be. One can even draw a simple line and see exactly to mm how long the segment should be.

This is likely induced by the incorrect handling of PDR printing by the printer and some auto-scaling stuff going on due to printer margins.

To avoid, it is best to import the plans in Libre Office - Draw. Fix the segments there and print the segment directly from the app.

In order to perform the fix, one may need to temporarily increase the page size to 100x100cm as the ellipse creating the segments is that big.

The exact dimensions of the segments are very important because the distance in the plans is fixed at 244mm between them (meaning they should be at a specific size). Again all of this can be verified in Draw.

Not having them exact is again inducing minor errors in the system.

I think Peter has summed it up nicely. The platform is for visual not AP so slight drift is not a problem, particularly with wide field EPs. 

Hopefully the thread title keeps it clear that this is a low tech, inexpensive solution aimed at those with limited DIY skills.  Anything more really requires more outlay and/or knowledge and skills. 
 

John

[AstralFields]

Almost there. There have definitely been some lessons learned along the way. 

1) Don't use any drill adapters to cut wood. The damn thing broke 80% along the way and I am having to cut the rest manually. Just get a small hand held wood cutter. I probably will for my 12" DOB version.

2) Use plywood. The type of wood I am using is not the ideal, the top board broke in two so I had to patch it up. It will likely add a bit of bounciness to the system but shouldn't be too drastic. I can always replace it later on with plywood.

3) Don't store your only 9V battery in a box full of metal parts. Few days later - voltage ZERO. Just when I was going to turn on the platform for the very first time.

4) Aluminum is a tough nut. Not all Aluminums are alike. I was going to use a 3mm bar to cover the segments but that thing was tough to cut. I even gave up of putting it under the pivot. I am just going to hollow out a small hole in the wood. So I just made the segments out of wood and put some rubber on top of them to cushion the roll.

All in all, few cosmetic cuts remaining but it really came along very well. Maybe Thursday I will get to test it on the Moon.

Edited April 17 by AstralFields

[AstralFields]

Mission Accomplished.

As they say, pictures speak louder than words. This is M3 with a more or less OK alignment. I don't have a proper DSO camera so this was with my cellphone through a 15mm eyepiece on my 8" DOB .. 80x magnification.

the Aluminum segments that you find in most plans are definitely not needed. Wood is a lot easier to deal with and lined with a bit of door tightening rubber it runs extremely smooth.. no jerky motions of the objects whatsoever even at 800x. There is some drift at this power, but it is smooth and mostly to not exact alignment/speed setting. I captured all of this on video of the Moon and will be compiling it into a nice 10-15 minute video of how I made the platform from start to finish with the key lessons learned.

The price tag is really small for this one, given the performance I am getting. Next time I am doing it with Plywood.

When you break it down , there are just few parts:

Plywood - about 30$

EQ 2 Motor - 37$ from Aliexpress with shipping

Wheels and pre-cut iron rod 0.8mm - 10cm long - about 10-15$

Some spherically curved bolts - 2$

Regular wood screws - 1-2$

optional:

Li-Ion rechargeable 9V batteries - about 8$ (which I bought)

A hand-held controller for the speed of the motor - they go for about 2$. I will make one as it was very frustrating having the fine tune the speed by going back and forth from the eyepiece to the motor.

All in all , a nice price tag of around 80$. A new one (albeit prettier) sells for about 500$ here with the same motor and same performance.. I may make a couple of these for a 12" DOB and sell them for 250$ each. Already two people expressed interest. It is far below my hourly wage when I count the time I need but it is fun and always nice helping out an astro buddy :).

The biggest advantage of building one your own is you get to simply make it fit your telescope exactly and you understand how it works. Also you can cut the segments exactly for your needs. By the looks of it, this one should be OK for the 12" as well , which I already have on the way.

It provides tracking for about 90 minutes, which is great and so comfortable that I found myself forgetting to reset the telescope after an hour of observation.

[PeterStudz]

@AstralFields Good to know that it all works. For a hand controller as long as you have some bits of wire you don’t even need to spend any money. Some people have separated the motor from the box (with circuit board & switches), joining the two with long wires. You can see the two separated in the Teleskop version - the motor at one end and the box with the electronics and switches at the other.

I thought of having a hand controller, but personally I haven’t found it to be a problem. I have a little volt meter across the motor terminals on my version. All I do is make sure it’s set to the correct number (for me 2.35 - 2.37 volts) at the beginning when I have to bend down anyway and keep it there. I rarely need to fiddle with it and often don’t touch the potentiometer for several sessions in a row.

Although the good thing about making your own is that you can personalise things to your taste/requirements!

Edited April 18 by PeterStudz

[AstralFields]

15 hours ago, PeterStudz said:

@AstralFields Good to know that it all works. For a hand controller as long as you have some bits of wire you don’t even need to spend any money. Some people have separated the motor from the box (with circuit board & switches), joining the two with long wires. You can see the two separated in the Teleskop version - the motor at one end and the box with the electronics and switches at the other.

I thought of having a hand controller, but personally I haven’t found it to be a problem. I have a little volt meter across the motor terminals on my version. All I do is make sure it’s set to the correct number (for me 2.35 - 2.37 volts) at the beginning when I have to bend down anyway and keep it there. I rarely need to fiddle with it and often don’t touch the potentiometer for several sessions in a row.

Although the good thing about making your own is that you can personalise things to your taste/requirements!

The thing about the controller.. I already have one laying around here, got it back last year where I built my own planetary motor out of Lego (long story) .. so it is just a matter of rewiring it to the platform. I did settle down on a constant speed towards the end of the observation but it just felt like I could use some minor micro tuning of the speed back and forth.

[AstralFields]

For those who may be interested to check on how it went