10” Equatorial Platform for Dummies

[westmarch]

3 hours ago, mdstuart said:

You call that improvisation...what about my end stops.

Good Luck with those! 😯

John

[mdstuart]

First light. That's odd the stars are going up with the motor on but drift to the left when the motor is off.

Top tip. The pointy end of the platform should be facing South NOT North!

So a 180 degree rotation of the platform and then point at Albeiro...super sharp view from the Orion dob as always. Turn on the motor....

WOW Albeiro just hangs their in the middle of the field of view. Called the wife who has a look and yes the double is still in the middle of the field of view.

So it all works perfectly. Next step is to add some paint to the platform.

 

 

 

 

 

[mdstuart]

Final completed platform. Just need to create a battery compartment.

[DWV]

Looks good!

You're right, if we are not using the full length, why not just cut it off even with the edge of the platform?

[mdstuart]

 This video shows the moon with the equatorial platform running. It just hangs there in view. 

[westmarch]

The platform really comes into its own when you are trying to spot DSOs that are on the edge of visibility - it gives you time to spot it with averted vision or wait until that moment of clear seeing.

John

[mdstuart]

It also allows me for the first time ever to take basic dso pics afocal with a smart phone. Recognise this?

[PeterStudz]

8 hours ago, mdstuart said:

It also allows me for the first time ever to take basic dso pics afocal with a smart phone. Recognise this?

M13, that is actually very good for a smartphone snap! Please can you also post  it in the “Imaging - Smartphone/Tablet” section of the forum.

Right, I’m going to start on making one. I already have the motor from my old EQ1 which I’m not using now anyway. 

[Mr Spock]

12 hours ago, mdstuart said:

 

 This video shows the moon with the equatorial platform running. It just hangs there in view. 

I can see it moves slightly. You might try turning the speed adjuster one eighth anti clockwise. It’s only a small difference though. 

[PeterStudz]

Just started on mine. Just one question - in the instruction documentation by@westmarch the southern pivot bolt is given as M20 - that’s rather wide/large bolt! - I’m guessing it should be something like M8, possibly M10.

Just finishing off the segments. I stuck down the paper template to the aluminium with some craft glue to make things easier for me. Will soak it off in WD40 when done. My woodwork is OK but I’m a bit rubbish with metal.

I’m a bit late to the party but this has got to be one of the best, if not the best, threads in the DIY forum. 

Edited July 12, 2022 by PeterStudz

[PeterStudz]

[mdstuart]

Yes m20 seems too big I used an M8 bolt for my pivot and it's fine.

Mark

[westmarch]

37 minutes ago, PeterStudz said:

Just started on mine. Just one question - in the instruction documentation by@westmarch the southern pivot bolt is given as M20 - that’s rather wide/large bolt! - I’m guessing it should be something like M8, possibly M10.

Just finishing off the segments. I stuck down the paper template to the aluminium with some craft glue to make things easier for me. Will soak it off in WD40 when done. My woodwork is OK but I’m a bit rubbish with metal.

I’m a bit late to the party but this has got to be one of the best, if not the best, threads in the DIY forum. 

Hi Peter,

It is a wide bolt and intentionally so. The Southern pivot carries a significant part of the weight of the whole rig. You can use a smaller bolt but risk it eventually digging out a pit in the softer aluminium block. I wanted to avoid the risk of judder from that. 

Good luck with your build. 

John

[mdstuart]

Sorry, yes follow the plan. I went for a smaller bolt but that was at my own risk!

Mark

[PeterStudz]

2 hours ago, westmarch said:

Hi Peter,

It is a wide bolt and intentionally so. The Southern pivot carries a significant part of the weight of the whole rig. You can use a smaller bolt but risk it eventually digging out a pit in the softer aluminium block. I wanted to avoid the risk of judder from that. 

Good luck with your build. 

John

Hi John,

Thanks for getting back to me. I’ll think I’ll have to limit it to an M12 - that’s the biggest bit that my drill can take! 

[PeterStudz]

Almost there. I lost some time due to holiday but once you’ve cut out the boards and aluminium arcs the whole thing quickly goes together. My Dob has a rather “solid” DIY base with large feet and I haven’t quite worked out how to secure it. But as soon as I had something that worked I could not resist giving it a go, the Dob just carefully plonked on-top. Didn’t have much time before the forecast clouds came in so I homed in on Saturn. Even at 300x (far too much for a sharp view) I could keep the planet centred. Went in to make a coffee and even after 4-5 mins Saturn (some drift of course) was still in the eyepiece. I could even make out 4 moons (a first for me), the advantage of having more time to observe before having to nudge. Now, just need to finish it off!

Nothing that different from the excellent instructions. And I have to say that @westmarch should get some sort of prize for this thread.  I know he’s taking ideas and inspiration from others but this platform is minimalistic, simple and straightforward to make that just about anyone can give it a go. All in the tradition style of the Dob. The only tools I used were a handsaw, hacksaw, electric drill, file, and some screwdrivers.

I did break a drill bit when drilling the fixing holes for the aluminium block, the end of the bit stuck fast. Cheesed off I went down the shed to see if I could find something as a substitute. In the end I used a scrap plywood block, a couple of penny washers to form a recess and a dome nut to sit on top of an M12 bolt. The dome nut is 18mm diameter which is similar to an M20 bolt with the threads filed off . Seems to work well with a smooth rotation.

I’m a veteran of the EQ1 motor drive. I had one for an EQ1 (my first telescope) and it was the best £28 I’ve spent in astronomy. It transforms the EQ1 into something useable. Although I did try and improve it by replacing the 9v battery with something with more beef and that’s rechargeable. I did find that I was going though 9v batteries far too quick and that this small battery didn’t do that well in the cold. For this I used a cheap 12v sealed lead acid battery (the type used in alarms) knocked down to 9v with an equally cheap converter. This pushes out a steady 9v almost whatever the temp and lasts an age before needing a recharge. I also added a little voltmeter over the motor terminals - the idea here (I know it’s not quite as simple) is that I could quickly dial back a motor speed that worked. Oh, also a proper size “knob” on the potentiometer. I’ll change the wiring around somewhat  but it’ll basically stay the same with a battery box on the lower board. I was also going to use a micro switch for a motor stop but playing around I felt that for security it does need some sort of physical stop. For that I just added a couple of wooden blocks and I might still add a micro switch on top of one of these.

PS - my drill can take a 25mm bit. I was wrong there! 

Edited August 4, 2022 by PeterStudz

[westmarch]

Hi Peter,

Excellent piece of improvisation and if stuff like this is not for tinkering with then why do we have so many cloudy nights?

If your dob feet can not be fitted into anything on the platform, try drilling two holes through the dob base and platform and using a long bolt with a lock nut on the platform, followed by wing nuts to secure the dob base to the bolts. I am sure there are any number of other solutions.

I hope you have many dark nights to enjoy it.

John

[PeterStudz]

Thanks John! For securing the base I had thought of simply getting some smaller rubber feet and replacing what I have (the cost is minimal). Or making a couple of small plastic/rubber/wood “studs” that are fixed to the bottom of the Dob. Obviously shorter that the Dob feet these would fit into a couple of raised recesses (blocks of wood with a hole) on the top of the platform. For the “studs” I’ve had my eye on synthetic corks from wine bottles. Although I’d need to drink another bottle of wine 🙂

[Time Traveler]

Can someone show me what the vns segments measure for latitude 39 degrees?

 

[westmarch]

12 hours ago, Time Traveler said:

Can someone show me what the vns segments measure for latitude 39 degrees?

 

Hi Terry,

Reiner Vogel does not list a VNS segment for 39 degrees, probably because you start to get into problems of platform instability at lower latitudes. As you get nearer the equator you have to consider substituting a circular segment as the southern pivot.

For 39 degrees you would probably be better considering a poncet type design.  There is a discussion about latitude and design type here (towards the end of the thread):  

https://www.cloudynights.com/topic/689330-equatorial-platform-cutting-aluminium-segments/

John

Edited October 31, 2022 by westmarch
better research

[Time Traveler]

Westmarch, I used the eq platform guide from "Equatorial Platform Design Compromises on this Build" right here on Stargazerslounge.  Do you not think that would work at 39 degrees?  i built it many months ago.  I actually forgot how I  came up with the north segments.  It seems to work pretty good at 30mm EP, but if I go more magnification, the object drifts worse.  Someone told me that maybe my math was wrong.  So I thought maybe I figured the segments wrong.  Anymore thoughts?

 

[Mr Spock]

Have you adjusted the motor speed? When I first started using mine it was over tracking, slowing the motor down a little click by click eventually got me to perfect tracking.

[westmarch]

Hi Terry,

Acurate segments are key to getting smooth tracking. At a relatively low latitude such as 39 degrees the VNS design will struggle.  If the segments were designed for a higher latitude, you can shim the platform to compensate slightly.  This involves lifting the south pivot by no more than 4 degrees. Again you may run into stability problems at full tilt so be careful. 

John
 

 

[Time Traveler]

Dear John, so vns is not the answer...which on would you suggest?  I guess I'll try making a different one.  Man, I didn't think 39° was so low!

 

[westmarch]

Terry,

I think you have to temper your expectations.  You are beyond the lower latitude that this design is optimised for but that does not mean it is not functional.

1. EQ Platforms are not going to give you EQ6 level tracking.

2.  If you are looking at DSOs, you are never going to be using high mag so a bit of drift in a wide FOV is not a game changer.  If this is not enough for you then try the following:

3. Shim the southern pivot.  

        (a) Your bottom platform should be level.

        (b)  Get a digital  inclinometer/protactor.  Only costs about $£10. Put it on the top platform and zero it.

        (c)  Incline the southern end of your upper platform with  wood packers until your inclinometer shows a 4 degree elevation.

        (d)  Measure the distance between the upper surface of the bottom platform and the lower surface of the top platform. That is your target elevation for the southern pivot.

        (e)  Get a longer bolt and put it through the southern pivot bolt hole. Now mark it at the measurement that you made in (d).  Cut it and round off the end.

         (f)  substitute it for your original bolt.

If you started off with segments designed for the minimum latitude that Reiner Vogel specified (46 degrees), then your 4 degree shim will have converted it to a  42 degree platform.

This, combined with Michael’s suggestion of trimming the speed, should give you a more stable target acquisition.

I can’t however emphasise enough! Check that you are happy with the stability of this setup at full tilt before committing your precious Dob to it, unsupported.

Good Luck!

John

Edited December 2, 2022 by westmarch