My Barn Door Build

[happy-kat]

Thanks for the extra thoughts.

My base is finished and the barn boards fixed on.

CD idea did not fit for my build.

My bolt will raise the top board.

The hinge is on the left, the board will open east to west.

Tomorrow should see it finished.

Jobs remaining:

Add a dowel to the handle to aid smooth turning

Attach the finder scope to the bracket and align to the hinge

Work out how many degrees the captive nut represents

Trial run

I am leaving the boards slightly longer then they need to be to give room to mount a motor in the future should it be worth a try.

[happy-kat]

Construction finished.

[udaiveer]

I mean using a CD as a scales marker with 60 divisions for 60sec.

How will u b able to know how much to rotate?

Also what is the distance of the bolt from the hinge? 9.4inch or 7.5inchs.?

[udaiveer]

I mean using a CD as a scales marker with 60 divisions for 60sec.

How will u b able to know how much to rotate?

Also what is the distance of the bolt from the hinge? 9.4inch or 7.5inchs.?

[happy-kat]

My distance is exactly right for the tpi of my bolt.

I have an application on my phone which I will mimic/follow for turning the handle.

I also have a scales marker on the top of the bottom board.

I don't envisage trying for longer than 1 minute.

[udaiveer]

The Seconds hand of a watch is a good reference to follow

[happy-kat]

The application I will be using compensates for tangent error so hopefully that will improve things.

[happy-kat]

Have had the first test run.

Good points, did not need to polar align our house orientation appears to have given me enough of a guide on where to place the chair to sit it on whilst compass north it appears good enough. The leveler worked very well with the 3 adjustable feet.

What do I still need to do I think a smear of silicon grease on to the threaded rod will help with smooth show speed turning.

I managed with a 55mm lens to get good tight 30 and 60 second exposures so really pleased. Comet lovejoy is nice and green.

I do need to use it with a combination of the intervalomater and my tablet as bulb mode for above 30 gives me unreliable sub lengths.

[udaiveer]

The threaded rod is straight so it will start getting harder to rotate. Grease or no grease the force of the tilting rod yanked out the bearing-Nut on the base okate.

U can use a thick rubber washer to get some more play(tilt)

[happy-kat]

The barn door is made from chipboard and is hard coated and the captive nut is sliding smoothly on the surface with not evident drag so there is no force on the bearing T nut in the base (hopefully).

...next time I see a motordrive on Astroboot even if they have 10 buy it... all gone now.

[Fred_76]

To compensate the tangent error, in the case your phone runs out of battery, just add a small steel plate grinded to the right profile as I explained here :

http://www.astrosurf.com/fred76/planche-tan-corrigee-en.html

Clear sky

Fred

[happy-kat]

Thank you very interesting. For the moment my long exposure demands are not pushing me into the area of tangent error but I will keep the information as if I sort a motor out I will need that as my rod length means I could in theory get 59 minutes on one exposure.

I could see a 3d printer knock that fitment out very easy. If I find the time I might knock one up in TurboCAD.

As a side note am finding the base extremely stable and easy to level with the adjustable feet. It is rock steady so thankfully that won't be a source of vibration.

[happy-kat]

With the barn door as it is I am able to get 60 seconds from the 55mm lens with about 50/50 for very tight stars versus images with a very slight trail visible on pixel peeping though I guess with the early runs using quite an elevation will have helped here, but 30 seconds is much eaiser to get right.

The example is a single jpg straight from camera just resized ISO 400 60 seconds f2.8/f3 (I do shoot in raw too).

[happy-kat]

Found a small CD so have added this to the handle it feels easier to turn smoothly, hope to try it out tonight.

The adjustable feet are working out brilliant for leveling the mount.

Mini CD handle update.

[happy-kat]

Whilst this is Mark I manual build I am always considering adding a motor, still torn between a electronically driven motor of a mechanically driven motor.

I have no coding skills or electronic skills and whilst pulled towards the challenge of a Ardiuno solution I think mechnical might win.

I will make a wedge as per Fred's earlier suggestion so tangent error will be minimised/removed.

Currently pricing both options up.

[cuivenion]

With the barn door as it is I am able to get 60 seconds from the 55mm lens with about 50/50 for very tight stars versus images with a very slight trail visible on pixel peeping though I guess with the early runs using quite an elevation will have helped here, but 30 seconds is much eaiser to get right.

The example is a single jpg straight from camera just resized ISO 400 60 seconds f2.8/f3 (I do shoot in raw too).

IMG_9373 (Large).JPG

Wonder what that blue/green fuzzy is, north west of the pictures centre.

[happy-kat]

That was lovejoy

[happy-kat]

I am swaying back to electronic, this site makes me think I could do a paint by numbers and have a go.

http://fstop138.berrange.com/2014/01/building-an-barn-door-mount-part-1-arduino-stepper-motor-control/

[cuivenion]

That was lovejoy

Thought so. Sorry for the thread hijack.

[happy-kat]

So that is the Arduino Uno ordered...

It has taken me three days to get Eclipse working with Arduino but it is now sorted and compiled a sample project OK so I took the plunge to go that way.

[happy-kat]

Lots of new parts ordered get to make a start with learning what I am doing with the breadboard I also included.

[Ags]

Good luck!

[happy-kat]

All the bits have now arrived all bar the cog to fit to the motor drive shalf.

[papabone]

I also am entering into trying to track without paying the nigh on £300. I have bought loads of arduino kit and steppers from China and 4 old laser printers ( 99p  each ) to disassemble for cogs and such. It seems to be a varied  learning curve involving carpentry, engineering and computer coding. Must get one finished for Astrocamp in May to take advantage of dark skies. Good luck with your build.

[happy-kat]

Thank you.

This is the one I am particularly following and again the code has been shared. I can't link it but it is on Flikr album called barn door mount.

Got it

link here

I think the next level up is a virtuoso mount on a wedge with that blue tooth adaptor that connects it to stellarium though it's accuracy for tracking for imaging is yet unknown. That I guess works out cheaper second hand and will have goto.

Good luck with building it in time.