Barn-door Tracker

[tuc]

Has anyone made a barn-door tracker?

[yesyes]

a what? ;-)

[bamus]

this is my project for next year (time permiting). Have got spare mtor after upgrading my eq5 to GOTO, so I will try to made it, so I can take it with me on holidays

[iamjulian]

Yes, several. Once I bought a telescope with an EQ mount I stopped making them. Anything specific you want to know?

[tuc]

Have you made the non-motorized kind that uses the quarter-turn

knob?

[Dave]

Yes. I made one nearly 25 years ago.

Comprises three pieces of chipboard a qtr inch Whitworth threaded rod and a coffee jar lid.

I did an article about it for Popular Astronomy a few years ago.

I could did it out and scan it in for downloading if it would be useful.

Dave

[iamjulian]

Yes, quarter turn every 15 secs was the way I did it. I made the very basic two planks of wood forced apart by a threaded rod with a wing nut. But error creeps in quite quickly. My most recent version I got a meter long threaded rod and bent it to a precise curve, like this: Astrophoto.ca

[Doc]

This is mine:

http://stargazerslounge.com/diy-astronomer/75703-my-barn-door-mount-project-photos.html

[tuc]

Yes, quarter turn every 15 secs was the way I did it. I made the very basic two planks of wood forced apart by a threaded rod with a wing nut. But error creeps in quite quickly. My most recent version I got a meter long threaded rod and bent it to a precise curve, like this: Astrophoto.ca

That looks really good. The "error creeping in" is what I wondered about. Do you have any photos? If not, then can you give me an idea of how well it works?

Thank you.

[tuc]

Hi Doc,

That looks good too. Were you happy with the results?

[Doc]

Not really to much wobble while turning the dial every 15 secs. If you connect a 1 RPM motor to the shaft then I bet you would get much better results, haven't tried yet.

[tuc]

Doc,

Yes, but what fun would that be!

I have a real love of simple gadgets-even if they`re not perfect.

[iamjulian]

Sorry, don't have any images. Depends what lens you are using. 30mm or below will be forgiving enough to get a heck of a lot of stars and the brighter messier objects, albeit small! If you start going above 100mm then you are going to see errors. But if you like it basic, and like a challenge. Why not calculate the rate at which you need to start increasing the quarter turns to correct the slowing of the pivoting arm.

[BinocularSky]

Yup, firstly a hand-driven one, then this motorised dual-arm job.

[astronymonkey]

I made one of these years ago and used to use it for photos upto 10minutes and it worked great. I reduced the error that occurs as the hinge opens more by making the loose end of the drive bolt sit in a small drill hole while tracking, this keeps the distance from the hinge constant and therefore keeps the opening rate the same.As long as the nut part can pivot slightly this seems to work ok.

They are easy to build and the hand driven version seems to work fine.

Cheers,

Astro