Barn door open or close?

[g-rex]

Have built myself a barn door tracker that I was thinking of making motorized. It seems the way to go is an Arduino using a stepper motor is the usual thing to do.

All the things I've read say hinge on the left and the door opens.

My question is if the hinge is on the right and the door closes does it still work exactly the same?  I'm guessing yes  but a bit unsure.

Cheers

Graeme

[vlaiv]

I think it does not make any difference as long as you make your motor spin the right way.

[Ruud]

Only if you use chickens to motorize it you should keep the barn door closed. You wouldn't want them to wander off.

[vlaiv]

3 minutes ago, Ruud said:

Only if you use chickens to motorize it you should keep the barn door closed. You wouldn't want them to wander off.

No one in their right mind would use chickens for this these days. Hamsters produce much lower tracking periodic error and smoother running drive.

[g-rex]

8 hours ago, vlaiv said:

No one in their right mind would use chickens for this these days. Hamsters produce much lower tracking periodic error and smoother running drive.

Like it! ?

[g-rex]

Reason I ask is that to open (or lift the door, camera and lens) will take a decent motor with some torque. 

But if it's closing its effectively coming down under its own weight, so surely a motor out of a clock (with gearing to make from 12 hr to 24hr) would suffice?

 

Am trying to keep things as cheap and simple as possible.

 

Graeme

[happy-kat]

Generally the hinge is on the left in the northern hemisphere and the boards open East to West.

However there was a build on sky at night magazine that did close instead of open and a member on here did build it.

[g-rex]

Thanks for that. Can you remember if it was built the same then? So it just closed east to west instead of opening east to west? 

 

What I'm trying to ask (and possibly not making a good job of it) is will the tracker I've built work if I have the hinge on the right, or do I have to somehow change bits on it to make it work this way?

 

Graeme

[happy-kat]

Loads of links on this post

Link here

[maw lod qan]

Does your build use a threaded rod being turned to lift the door? The itsy motor i've on mine turns 1 rpm and it's works pretty good. 

[g-rex]

Brilliant, thanks for that link happy-kat! 

Am at work but will have a read through that later. ?

[g-rex]

9 minutes ago, maw lod qan said:

Does your build use a threaded rod being turned to lift the door? The itsy motor i've on mine turns 1 rpm and it's works pretty good. 

Yes. A curved rod. M6 bolt which requires to be turned at 1rpm.

Can I ask what motor you used and is it a controlled stepper motor or just a straightforward 1rpm motor?

Thanks

Graeme

[Peter Drew]

I think the pressure on the drive will be the same in both cases. There is a considerable mechanical advantage with a screw thread so motor power shouldn't be too much of an issue.    ?

[happy-kat]

I never found a 1rpm motor so got a higher power one that I will control by code, if using a mechanical design then you could use a power knob and just get the amount right for 1pm. 

[vlaiv]

1rpm can be easily implemented with stepper motor, you don't even need micro stepping. 200 step one will need step fired every 0.3s to get 1RPM - that is fine enough stepping not to be noticed on small focal lengths.

[g-rex]

Thanks for the replies.

Some food for thought.

I'm comfortable making things but electronics are a bit of a dark art to me. Was hoping to steer away from stepper motors but guess I need to do some research on them. 

 

One more question (sorry)

I have a EQ2 mount with a Skywatcher 130 on it. If I bought a Skywatcher motor for it and piggybacked the DSLR on this do you have any idea if this would be more or less accurate than a barn door tracker? 

My thinking is if it's as accurate I've got the motor to help with viewing too.

 

Thanks

Graeme 

[happy-kat]

I wouldn't piggy back as the telescope is extra weight and wind sail.

You'll have to fashion a way to polar align the eq2. Plenty to research there.

[g-rex]

Still learning polar alignment (only just got it) but I would've aligned the telescope/mount with the red dot finder I have. The point about the wind is a good one. Especially as where I live is quite open.

Yeah, definitely a steep learning curve! 

Thanks for the advice. It's appreciated. Will make use of these cloudy nights by trying to soak up as much info as I can.

 

Cheers

Graeme

[happy-kat]

You polar align the mount (not telescope).

The earth rotates on an axis. Where you live the latitude is your position. Polaris (well really the north celestial pole) isn't moving everything rotates around it. The angle from where you stand to the NCP is your latitude. You align the mount to that so that you can track the rotation by just turning one axis, the RA axis. Once aligned the telescope can point anywhere.

I won't mention the meridian flip.

[g-rex]

Been watching plenty of YouTube videos on this and have it straight in my head.

Just need some clear nights to get out and practice now.

[Chriske]

I'd make it 'opening' motion.

[leeseafish]

If you build the tracker as specified and align it with the s pole, in effect rotate it 180 degrees on the tripod, then it will track ok if you reverse the motor.  Have a look at the photos on my site - http://leeseafish.uk/AstronomyMountsBarn.html

 

[maw lod qan]

On Saturday, March 09, 2019 at 06:41, g-rex said:

 

I got it from amazon, 6v battery runs it through a pwm. Everything didn't cost 15 dollars.