Polar alignment scope for a barn door tracker?

I'm writing down parts I need to build a barn door tracker, and I'm stuck on the polar alignment scope. I'm not sure what to use. I want something a little more accurate than a straw

Should I get a polar alignment scope like this one from Orion (but it's not illuminated, hmm...), or something like a right angle illuminated finder scope? Preferably it'd have a reticle with markings at known degrees so I could find Polaris and then get as close as possible to the celestial pole.

Any suggestions?

Badger49456 wrote in post #11027370
I'm writing down parts I need to build a barn door tracker, and I'm stuck on the polar alignment scope. I'm not sure what to use. I want something a little more accurate than a straw

Should I get a polar alignment scope like this one from Orion (but it's not illuminated, hmm...), or something like a right angle illuminated finder scope? Preferably it'd have a reticle with markings at known degrees so I could find Polaris and then get as close as possible to the celestial pole.

Any suggestions?

A straw is far too small an aperture... you need a larger tube with home made cross hairs on the end

I've never made a barn door tracker but I do have an astrotrac, so same principles.

I think the answer to your question will come from thinking about how you intend to mount it on your tracker. Will you have a way of adjusting the collimation of the polar scope with the hinge of the tracker? How accurate will it be? Something like a finder scope mount with three screws would be good.

Then how much play is there in the hinge? No point having super accurate polar alignment if the hinge can wobble from side to side.

Finally, if you're only doing wide field then it doesn't have to be very accurate, but of course the more accurate it is the more you can do with it.

Sorry I don't have an answer, but just some things to think about.

Badger49456 wrote in post #11027370
I'm writing down parts I need to build a barn door tracker, and I'm stuck on the polar alignment scope. I'm not sure what to use. I want something a little more accurate than a straw

Should I get a polar alignment scope like this one from Orion (but it's not illuminated, hmm...), or something like a right angle illuminated finder scope? Preferably it'd have a reticle with markings at known degrees so I could find Polaris and then get as close as possible to the celestial pole.

Any suggestions?

Cheap air-rifle sighting scope perhaps? I have been looking at using a green laser for my barndoor project (currently stalled ) but I know that a lot of people don't like lasers.

Badger49456 wrote in post #11027370
I'm writing down parts I need to build a barn door tracker, and I'm stuck on the polar alignment scope. I'm not sure what to use. I want something a little more accurate than a straw

Should I get a polar alignment scope like this one from Orion (but it's not illuminated, hmm...), or something like a right angle illuminated finder scope? Preferably it'd have a reticle with markings at known degrees so I could find Polaris and then get as close as possible to the celestial pole.

Any suggestions?

Are the plans for this barn door tracker available online? I would be interested in seeing them.

It seems the hinge is an important component in this build, and the rifle scope could be the way to go.

the jimmy wrote in post #11064898
Are the plans for this barn door tracker available online? I would be interested in seeing them.

It seems the hinge is an important component in this build, and the rifle scope could be the way to go.

You might find THIS interesting.

Thanks for all the suggestions. I think I do have an air rifle scope around, and that should be good enough to play around with at first, at least to get the feel of doing it a few time.

I'm going to try to emulate Gary Seronik's plans availabe here http://www.garyseronik​.com/?q=node/52 I like the compactness of his and it looks fairly straightforward.

Badger49456 wrote in post #11069438
Thanks for all the suggestions. I think I do have an air rifle scope around, and that should be good enough to play around with at first, at least to get the feel of doing it a few time.


I'm going to try to emulate Gary Seronik's plans availabe here http://www.garyseronik​.com/?q=node/52 I like the compactness of his and it looks fairly straightforward.

Thanks for the link, that's a cool looking tracker compared to others I've see on the web. I would have to belive the alinement of the hinge is important, and having two of them might add to the possibility of error, or maybe I am over rating this...

the jimmy wrote in post #11075265
Thanks for the link, that's a cool looking tracker compared to others I've see on the web. I would have to belive the alinement of the hinge is important, and having two of them might add to the possibility of error, or maybe I am over rating this...

Well you might be right, and I've thought about that and simply using a single 6" hinge. I just ordered the motor and gears today so hopefully I'll have something to share in the coming weeks!

martyn_bannister wrote in post #11031927
Cheap air-rifle sighting scope perhaps? I have been looking at using a green laser for my barndoor project (currently stalled ) but I know that a lot of people don't like lasers.

You've not seen mine yet have you Martyn? Excellent for pointing out things in the sky, but produces a blindingly bright dot when shone on the ground or a surface. And it's only a 20mW one as well. So yeah, not really a very good idea. Plus when it gets quite cold it hardly works at all.

Adrena1in wrote in post #11124663
You've not seen mine yet have you Martyn? Excellent for pointing out things in the sky, but produces a blindingly bright dot when shone on the ground or a surface. And it's only a 20mW one as well. So yeah, not really a very good idea. Plus when it gets quite cold it hardly works at all.

Not yet, no But I'm hoping to get out at some time in the next six months. I have bought a laser for my project, but hardly dare take it out