10” Equatorial Platform for Dummies

[Astronomist]

1 hour ago, Mr H in Yorkshire said:

no-one has made their EQ platform with the altitude axis as an integral part

Pretty sure I saw a couple of threads about this on CN a while back, and I think at least one person has built one. Trouble is it makes the whole thing a lot more difficult to transport, as in many EQ platforms the top and bottom halves aren't actually held together. also it makes life difficult if you want to use DSCs as you cannot transition to pure altaz.

Edited January 13 by Astronomist
spweling and gramer

[Mr H in Yorkshire]

2 hours ago, Astronomist said:

Trouble is it makes the whole thing a lot more difficult to transport

I appreciate that as I said about being bulky, but it would be possible to design so that the upper alt box could detach from the azimuth bearing.  Like most constructions, it's a matter of whether there were any gains that were worth the effort and perhaps added complexity.

[Jimmy81]

So I finally got an opportunity to test my new platform a few nights ago. It was freezing cold so didn’t spend too long outside but I could not eliminate the drift. I made sure the platform was level, fiddle with motor speed adjustment but still no joy. After going through the whys in my head - was the motor defective, are my segments not precise enough etc etc I gave up. 
Then it came to me. In all the excitement of trying out my new ‘toy’ I’d forgotten 1 crucial setup process - I did not polar align the platform!!!! Man I felt like a complete idiot. Anyway, hoping to test it again this week with clear skies forecast, just hoping the temperature rises a bit 🥶 

[westmarch]

On 02/07/2022 at 07:06, mdstuart said:

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.

 

 

 

 

 

It’s a mistake we’ve all made. 😁

Good luck with your next outing. 
 

John

[GasGiant]

This is a great thread, really useful.

Maybe I missed it, Can someone explain how you polar align please ?

Is it simply pointing the pointy end north as accurately as possible ? 

Also, im at 51 degrees. Should I use the 50 or 52 degree wedge ? 

Edited January 25 by GasGiant

[PeterStudz]

1 hour ago, GasGiant said:

This is a great thread, really useful.

Maybe I missed it, Can someone explain how you polar align please ?

Is it simply pointing the pointy end north as accurately as possible ? 

Also, im at 51 degrees. Should I use the 50 or 52 degree wedge ? 

“Maybe I missed it, Can someone explain how you polar align please ?

Is it simply pointing the pointy end north as accurately as possible ?”

For visual that’s accurate enough and all you need to do. There are ways of getting it more accurately aligned, but unless you are trying to do long-ish exposure astrophotography don’t worry about it now.

”Also, im at 51 degrees. Should I use the 50 or 52 degree wedge ?”

It doesn’t matter… 50 or 52 will be more than good enough. 

[GasGiant]

Magic. Thank you @PeterStudz

[westmarch]

19 hours ago, GasGiant said:

This is a great thread, really useful.

Maybe I missed it, Can someone explain how you polar align please ?

Is it simply pointing the pointy end north as accurately as possible ? 

Also, im at 51 degrees. Should I use the 50 or 52 degree wedge ? 

The pointy end goes South - not North .  You should line up the platform so that the point of the A Frame base is pointing directly away from Polaris. As Peter says, near enough is good enough.🙂

John

Edited January 26 by westmarch

[GasGiant]

@westmarch  South. Gotchya !!  The pics show it pointing North, before I read this 🙂 

 

Here is my progress so far. Started today at around 10 and cracked on till around 4.  The linked plans have been fantastic, thank you for taking the time to run through things.

I have changed a couple of things. 

I bought a ball housing for a more solid fit, Im trying to eliminate any wobble I might come across. Less slop in the system as it were. 

The bearings and shaft I have kinked over slightly. If they are placed as shown then as the platform arcs one side of each wedge lifts slightly losing contact with the stip. This way I get full contact as it goes through the arc.  Maybe Im over thinking things but Im hoping it will eliminate potential slippage !!   I think If I had used thinner strip then it would have been fine, however ive used 10mm strip. 

The motor is on its way, by the time thats here it will be ready to rock !Gulp.   Im really hoping Ive done everything correctly and it works well once set up.

Here are some build pics

Edited January 26 by GasGiant

[westmarch]

Very impressive!  Love the Southern bearing - ingenious. 
 

You do know it’s going to be cloudy now til Easter. 
 

John

[PeterStudz]

Looking good @GasGiant! And thanks for sharing.

The only issue you MIGHT have is it slipping due to the thicker arcs. But then probably not. After all, there are other EQ platforms like that eg the Omegon at FLO.

[GasGiant]

 

 

Its all ready to rock tonight !! should we get even a few stars out  it should be enough to check. Wish me luck 🙂 

 

 

[PeterStudz]

Looking excellent! I could not do without mine now. Eg just looking at Saturn at high magnification, going back inside to make a cup of coffee, and when I get back out still finding Saturn in the FOV is great. And that’s before I get to observing

[GasGiant]

I have high hopes and cant wait to try it tonight fingers crossed @PeterStudz  I just hope I have made it correctly! LOL 🙂 

[PeterStudz]

Just now, GasGiant said:

I have high hopes and cant wait to try it tonight fingers crossed @PeterStudz  I just hope I have made it correctly! LOL 🙂 

Even if it needs some adjustment it looks like it’ll work to me.

If you had a white light solar filter you could try it now. Well, it’s sunny here. This does remind me - if you haven’t got a white light solar filter it’s another great little DIY project.  Very simple too and well worth having. 

[GasGiant]

1 minute ago, PeterStudz said:

Even if it needs some adjustment it looks like it’ll work to me.

If you had a white light solar filter you could try it now. Well, it’s sunny here. This does remind me - if you haven’t got a white light solar filter it’s another great little DIY project.  Very simple too and well worth having. 

Na, annoyingly I dont 😞  I have some film coming for my B-day soon ! I knew I should have bought some earlier. lol

[westmarch]

That looks like a fine piece of work!  You have the makings of a cottage industry there. 
 

Only one question, are those Velcro pads that you are using to hold the Dob in place?

John

[GasGiant]

Hi @westmarch

 

They're rubber anti slip pads. I was hoping they would be enough to hold the dob in place.

However,  after a quick test I thought it not worth the risk so added the barriers !! 

Im all set up and its getting dark soon. fingers crossed.  

[westmarch]

Good Luck and hoping you get some clear skies. 👍

[GasGiant]

IT WORKS 🙂 

 

So, I get a very slight drift but I cant slow the motor down anymore.  

I have an idea what it is though. The two shafts instead of being 8mm are 15mm. I think the change in diameter has altered the 'gear' ratio.  If these shafts are smaller diameter then they will run slower on the wedge. I should then have more wiggle room with the speed controler.  I think 😁

I will whack em on the lathe and turn them down to 8MM

Edited January 28 by GasGiant

[PeterStudz]

13 minutes ago, GasGiant said:

IT WORKS 🙂 

 

So, I get a very slight drift but I cant slow the motor down anymore.  

I have an idea what it is though. The two shafts instead of being 8mm are 15mm. I think the change in diameter has altered the 'gear' ratio.  If these shafts are smaller diameter then they will run slower on the wedge. I should then have more wiggle room with the speed controler.  I think 😁

I will whack em on the lathe and turn them down to 8MM

Well done! And welcome to the club😃.

For mine it’s bang when the motor is running at approximately half speed. Could well be the diameter of the shafts. I’m sure it can be shorted. 

[Orange Smartie]

I have joined the club! I had to go slightly off-piste with my top board, as the feet on my Stella Lyra 10" must be a bit wider apart than those on the plan. So my top board is a little wider than the base board, but it still feels very stable. I need to do a few little mods; I'll probably chop the ends off the ellipses as they serve no useful purpose as far as I can see - on my wedge, one side hits the stop way before the thin end is reached.

It also needs to be painted or varnished.

I managed to get a quick test on Jupiter this evening, before clouds set in. This design really works! Thanks to the OP for sharing, I think it will revolutionise my viewing.

Please ignore Mrs Smartie's foot, which has phot-bombed my pic.

[GasGiant]

55 minutes ago, PeterStudz said:

Could well be the diameter of the shafts. I’m sure it can be shorted. 

Im almost certain it is. Its not drifting a lot, but its enough to annoy me 🙂 

[GasGiant]

@Orange Smartie  Excellent ! So nice being able to get a good time on Jupiter without nudging every 20-30 seconds ! 🙂 

 

[PeterStudz]

@Orange Smartie Looks great! I chopped/rounded the ends off my arcs as during testing my daughter managed to catch her ankles even though I told her to watch out. And as you say they aren’t necessary and don’t do anything.