500mm on a motorized barn door tracker?

I'm looking at the feasibility of putting my 500 on a barn door tracker. I have a gitzo 3541 tripod with a markins q-20 ball head which will be able to hold the weight. I'm just curious how hard it would be to fine tune the motor so it runs exactly at 1rpm?

Also does anyone have any recent tutorials on building a motorized one. There's plenty of non motorized tutorials. Here's the newest one I could find http://www.garyseronik​.com/?q=node/52

I seem to remember someone on here using a motorized mount and getting good results. All help is greatly appreciated.

Thanks,

Travis

There's no reason it can't be done but the 500 is a lot of lens and with the camera is quite heavy for a barn door. I would approach the project with all heavy duty and rigid construction as a priority.

Paxonator wrote in post #15485806
Also does anyone have any recent tutorials on building a motorized one. There's plenty of non motorized tutorials. Here's the newest one I could find http://www.garyseronik​.com/?q=node/52

I seem to remember someone on here using a motorized mount and getting good results. All help is greatly appreciated.

Thanks,

Travis

Start HERE this is in the Astronomy fourm in the photo sharing section, the thread is "You Don't Need a Telescope" post 1244, and it continues on. I am also interested in building one of these, post back in this thread any progress you make, thanks

Thanks Steve and Jimmy. I may talk to the guys at work and see if they could machine some parts for me.

I was looking at the astrotrac but it's pretty expensive. I figured I could whip something up and try it out for much less. I would also learn a lot more during the process as well.

I guess the one thing I also don't have is the tilt head that sits under the tracker.

well a tilt head is no different than a pan head with an angle finder on it. You can get some pretty strong ones from smith victor and the 1980's velbon stratos heads are really cheap on ebay. You can get a motor drive for cheap on amazon also http://www.amazon.com …rds=telescope+m​otor+drive

calypsob wrote in post #15517672
well a tilt head is no different than a pan head with an angle finder on it. You can get some pretty strong ones from smith victor and the 1980's velbon stratos heads are really cheap on ebay. You can get a motor drive for cheap on amazon also http://www.amazon.com …rds=telescope+m​otor+drive

Thanks! So with that motor drive what does that all do? How does it attach to the threaded rod to spin it? I need to do more reading but if it does what I'm hoping it would make things easier. Especially since it's more readily available online.

*EDIT*

I just realized I could probably use my gimbal head as a wedge. I just need to mount an arca swiss plate to the barn door tracker and as far as I can tell it'll work.

Paxonator wrote in post #15521991
Thanks! So with that motor drive what does that all do? How does it attach to the threaded rod to spin it? I need to do more reading but if it does what I'm hoping it would make things easier. Especially since it's more readily available online.

*EDIT*

I just realized I could probably use my gimbal head as a wedge. I just need to mount an arca swiss plate to the barn door tracker and as far as I can tell it'll work.

Gimbal head would work to get the angle but does it have an angle scale on it? If not you can get a digital angle finder from harbor freight for $10. There are also some iphone apps that are angle finders but might not be as accurate. I have only recently started contemplating the use of an EQ mount motor to power a barndoor tracker because I am going to get rid of an old cheap eq mount but keep the motor. http://garyseronik.com​/?q=node/52 I assume the gary seronik method would work and a gear could be connected to the clockdrive motor instead of using the motor drive that Gary uses. The celestron clockdrive has a speed knob which has no presets so you need to center an object in the viewfinder and increase the speed from slowest to fastest until it stays in the center of the viewfinder. Honestly this would be pretty easy to do with a 500mm lens because the field rotation would cause stars to move out of view pretty quick, it would be a little more tedious with a wide angle because it would take probably around 10-15 minutes to tell if a star has moved away from the center of the frame. Finally remember that the moon, planets, and stars all need different speeds. The speed of tracking stars is called side real, the moon is called lunar, and planets are called planetary of course. If I remember correctly, the stars move the fastest.

Thanks for all the info Wes. No I don't think there's an angle finder on the gimbal head. And I didn't know things moved at different speeds. This may be a harder venture than I thought.

I'll do more digging on how I can attach that celestron motor to the threaded rod. If i ever manage to get this thing to work I'll post some pictures.

Cool, I don't think it would be very difficult because the motor has a hollow tube with a tension screw for grabbing the ra and dec axis knobs so you could probably connect to a metal axle that feeds through a gear pretty easily.

Hi all. Just wanted to stop by and tell you that I've started to build a motorized barn door tracker right now. Going to order a Celestron Logic Drive anyday as powersource and hopefully it will work. Camera attached on tripod head - the rest of the components will be made in aluminium and some 3D-modeled plastic parts (too lazy milling them out of alu. right now). The concept of it all comes from "www.garyseronik.com..​....." I think it will be finished in a week or two (too much at work now).

KingRiver wrote in post #15552410
Hi all. Just wanted to stop by and tell you that I've started to build a motorized barn door tracker right now. Going to order a Celestron Logic Drive anyday as powersource and hopefully it will work. Camera attached on tripod head - the rest of the components will be made in aluminium and some 3D-modeled plastic parts (too lazy milling them out of alu. right now). The concept of it all comes from "www.garyseronik.com..​....." I think it will be finished in a week or two (too much at work now).

Sounds good, looking forward to seeing photo's of the tracker, and images taken using it. If possible would be nice to see pics of various stages of the fabrication process.

KingRiver wrote in post #15552410
Hi all. Just wanted to stop by and tell you that I've started to build a motorized barn door tracker right now. Going to order a Celestron Logic Drive anyday as powersource and hopefully it will work. Camera attached on tripod head - the rest of the components will be made in aluminium and some 3D-modeled plastic parts (too lazy milling them out of alu. right now). The concept of it all comes from "www.garyseronik.com..​....." I think it will be finished in a week or two (too much at work now).

Rad, keep us posted.. I actually realized today that surplusshed.com has a category for gears and they are cheap, like 40 cents cheap. Most of them are nylon but you may find one that can do the job.

OK, don't have enough time at the moment but so far the alu-plates and gear with rod is finished. Just going to get the plates its final shape ..... still waiting for the drivemotor. The tripodhead just arrived yesterday. Ballhousing and gears printed in 3D printer, nice to print practically whatever models you need . Sorry if bad pictures but had my pocketcamera at that moment. Will post picture when all is complete and assembled.

WHAT ! thats really cool that you have access to a 3d printer and it looks like you have gotten a really good curve on that thread. I have actually been drawing a barn door tracker in autocad that uses one giant gear with a camera bracket on the front instead of the curved thread... This looks like it will work out nicely, it may work out in your favor to print some 3d hinges which can slide over a 1.25" tube so you can use the tube as a polar scope and the axle for the hinge at the same time. Very cool, please keep us posted. Also if you dont already have a 3 way geared head I found one that orion sells for cheap http://www.telescope.c​om …Motion-Adapter/p/7033.uts you may want to get an angle finder from harbor freight to get your latitude as well.

Yeah, it's really nice to have access to a 3D-printer. Here at work we use Solidworks for CAD and 3D-models. Luckily we do have Solidworks engineers and printer in the department where I work. At the same time I do have access to the complete workshop also.....milling,turni​ng,welding etc.