14 replies to this topic

[Saxxon]

After spending most of the past few days looking I was wondering if someone could possibly guide me to a kit for a motorized barn door mount. I feel competent enough to build a non-motorized mount but the guides I have read on building a motorized mount and posts asking for advice on them, all seems like gibberish to me (gear ratios, motor speeds, speed controller, etc). I don’t understand the electrical side of it all (which makes me feel even less intelligent). Does anyone sell unassembled kits or is this something I will have to bug you guys about over and over again to get a motorized version working?

[KevinS]

Gary Seronik has a very elegant design and plans online. There is a tiny bit of electronics involved but his plans are very thorough.

http://www.garyseronik.com/?q=node/52

Depending on your needs you could just go with a motorless version.

[StarStuff1]

A moterless version can work very well. I built my first one for Comet Halley in the mid 80s and did a couple more after that. No batteries required.

[Saxxon]

I was hoping for an easy option for a motorized version simply because I felt it would be more accurate, with human error and all. But I will build a non-motorized version and see what comes of it. Gary Seronik’s build was what I was looking at as basis for my build. His instructions are very good and clear but as I said I am not electronically inclined (on the circuit level) and when he does the diagram for the motor control I may as well be trying to analyze a Picasso painting.

[Saxxon]

I also wanted to ask, what kind of weight capacity is there on a non-motorized barn door mount? I'm assuming on a motorized one, it would be whatever the motor can move. on a non-motorized one is it's limit my hand power? just wondering if I ever put a small scope on it, if it would handle it ok. I know barn doors are designed for wide field but it would seem with good alignment it should matter to much. let me know if I am way off on this one.

[StarStuff1]

Typically a barn door tracker is used with a wide angle lens and up to a short longer lens. I have made decent comet photos with a 135mm telephoto lens. I tried using an 80mm f/5 scope a couple of times and the results were not satisfactory. I suppose you could really scale up a tracker to handle a small scope but then it makes more sense to use an EQ mount.

[Saxxon]

Yea, my plans were for the foreseeable future to use the mount to take wide field photos using an 18mm lens then maybe use a 200mm zoom lens I got for free. Then maybe move up to a smaller scope. The EQ mount was an option I was looking at but with $$ being used for other important things (custody, vehicle, etc.) I was hoping to take shorter steps in moving up in gear.

On an unrelated question, I was looking at the Orion EQ-1 mount with the added drive system. Cost wise would be about the same since I would have to buy a drill to do the wood work (mine was stolen last month). What would be a better choice for wide field only? a barn door or the EQ-1 (also looking at iOptron Skytracker since it is kind of in my price range). So, just in your guy’s opinion, Barn door, EQ-1 (drive system) or the iOptron Skytracker?

[StarStuff1]

Wide field only? Barn door tracker is the least expensive option and should do a good job for you.

You will need a drill anyway but if working with wood then it is not absolutely necessary, just a slower build. Check local pawn shops amd you may find your drill or a good deal on another one. Garage sales offer the best prices. Last year I found a small table saw (8-in) with an almost new blade for $20. Even tho I have a 10-in contractor's grade table saw the small saw has come in handy.

[Saxxon]

I'll make a stop on my way home from work today and see what I can find at the pawn shop here. Does anyone have a recommended non-motorized barn guide? Or should I just go off Gary's design and modify it for no motor?

[Geo.]

Start without the complexity of a drive. If it grows on you you can elaborate. You've got to remember that this isn't practical exercise. These were called "Scotch" mounts for a reason. In the day, a tracking EQ mount was a rare and expensive item. Now a CG-5, which is an excellent mount for wide field camera shots, will run you a hundred and a tracking drive another $30, or about the cost of a modest lunch for six in a NYC Deli.

The only reason I can think of to do the barn door is for the fun of building a bare bones tracking mount from found materials. Any kit would have such a limited market that it would have to cost you as much as that used CG-5. 'scuse me, I got'ta tear down the microwave that died yesterday and see what's usable in there ...

[don clement]

An easily implemented improvement for the “barn door” mount I can see is to replace the door hinges with a strip of spring tempered metal such as spring steel or beryllium copper. The advantages over door hinges are: no slop, no stiction or slip-stick movement, and no lubrication required. An example of a strip hinge is this Hermann Schmidt surface gage. https://www.hschmidt.com/index.html

Don Clement

[Ed Jones]

Actually these are really darn easy to make. For a non-motorized barn door you should get a brass threaded insert from Home Depot and place it in the middle of a wood circle. This will turn 1 rev. per minute. Mark graduations on it every 5, 10 or 15 seconds. If you use 1/4-20 then get a threaded rod and bend it into an 11.43 inch radius (draw it on paper and then bend it to match). Fasten this curved bolt on one of the barn doors 11.43 inches from the hinge and make sure it travels smoothly through a hole in the other door. Mount a camera swivel post on the top board, stick it on a camera tripod, line the hinges up to Polaris and you're ready to go. You can find clock motors on Ebay such as this one pretty cheap and McMaster-Carr sells plastic gears so you get less vibration from turning it manually. Have fun.

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[Saxxon]

Thank you all for the input. I have decided to build a non-motorized version this weekend. while I wait for parts to build the motorized one (unless I can find a 1rpm motor at home depot, which I doubt). I live in Juneau, Alaska and shipping usually takes a week at its quickest without spending an arm and a leg on just shipping.

If it isn't asking too much, would anyone be willing to guide me in the direction of a way to hook a 1rpm motor to whatever kind of circuit is needed to be able to run it off of batteries? I have to drive 45 minutes away from the city for a good vantage point. I’m hoping to just have to connect wires from motor > circuit board (pre made) > battery pack (and what kind of battery (pack) needed to run the motor effectively). (Forgive the simple explanation; I don't know the technical terms)

[Anil]

Thanks for the nice link KevinS

Gary Seronik has a very elegant design and plans online. There is a tiny bit of electronics involved but his plans are very thorough.

http://www.garyseronik.com/?q=node/52

Depending on your needs you could just go with a motorless version.

[dobsoscope]

Did you build this at the end?