Mountings and Controls For Widefield Imaging Rig

[Gina]

An alternative to having the same cage/frame for all would be to have a separate one for each lens.  The lenses have different positions where the support ring can be placed and it might be easier to use different versions of cage/frame.  This would mean that the support rings could be permanently fixed to the cage, maybe with the cage in bolt together sections.  This will need some thinking about and possibly test versions.

[Gina]

Here are screenshots showing models of the 135mm and 45mm lens support rings, split into two pieces to enable them to be fitted round a fixed part of the lens and hold it tightly.

[Gina]

And the camera support ring...

[Gina]

I now have my RepRap style "GinaRep Pilot" 3D printer working pretty well and will be printing the parts in the next few days.  I've already printed a test for the framework with large spur gear built in.  The gear is about 150mm OD.

[Gina]

Now printing a test camera support ring.  Added a hole for cables to go through to design above.

[Gina]

These two photos show how the camera will be supported.

[Gina]

135mm lens support ring plus focus sextant gear.

[Gina]

Model of rotation framework extended to include the filter wheel.  The gap at the front takes the part that clamps the camera and provides a gap for ventilation of cooling air from the camera.

[Magnus_e]

Looking good  Makes me really want a 3d printer.

Just one question. When / if you move to INDI, have you thought about how to control the zwo efw? From what I can tell, it's not supported at the moment.

My 100% INDI observatory has been working mostly without issues (other than clouds) since late November. A couple days ago I committed to the zwo efw (7 slot, non mini) with asi 1600mm-c, zwo lrgb and baader nb  and so I will do my best in reverse engineer the efw driver. Have not done that before, so it could take a while. UPS estimates delivery for February first... hopefully it will get here sooner. Will read trough some more making Linux support from windows drivers in the mean time.

I downloaded the zwo efw ascom driver with no sign of a Eula, so reverse engineering it should be ok.

[Gina]

Thanks Magnus   Yes, I have thought about the ZWO EFW.  I think I read that someone had written or modified an INDI driver for it - I'll have to see if I can find it.  Should be in the INDI forum.

I'm also thinking about investigating writing INDI drivers as I shall want one for the rotation drive.  Alternatively, I believe there's an Arduino INDI driver so I might look at that way of controlling it - might be easier than writing a custom driver (or might not be ).  I shall want to control focus and if I go for zoom lenses, the zoom too.  ATM I have an Arduino sketch and a Visual Basic front end for remote focus control.  The VB control app needs windoze, of course.

[Gina]

Run a slicing test and that model of rotation framework would take over 6 hours to print with my current printing parameters.  Also, over 50m of 1.75mm filament.  I may well alter the model to reduce both printing time and filament usage, at least for test purposes.  The time is not a problem as I could let it run overnight - the g-code turns the printer off when printing has finished but I don't want to waste filament.

[Magnus_e]

18 minutes ago, Gina said:

Thanks Magnus   Yes, I have thought about the ZWO EFW.  I think I read that someone had written or modified an INDI driver for it - I'll have to see if I can find it.  Should be in the INDI forum.

I'm also thinking about investigating writing INDI drivers as I shall want one for the rotation drive.  Alternatively, I believe there's an Arduino INDI driver so I might look at that way of controlling it - might be easier than writing a custom driver (or might not be ).  I shall want to control focus and if I go for zoom lenses, the zoom too.  ATM I have an Arduino sketch and a Visual Basic front end for remote focus control.  The VB control app needs windoze, of course.

You are correct, there is a driver for the zwo wheel http://www.indilib.org/forum/focusers-filter-wheels/1523-zwo-efwmini-filter-wheel.html?limitstart=0

I have made some indi drivers myself, that is I have used existing libraries that control devices, and made them work with indi.

There are tutorials for any type of INDI device, that can be used as a starting point. You can have a look on how to do this on my GitHub. https://github.com/magnue

Perhaps you can use some of your existing code, for indi control. 

[Gina]

That's great - thanks very much Magnus

[Gina]

Added a bit more to the rotation framework taking it up to the 135mm lens support ring and clamp.

[Davey-T]

Hi Gina, would it be possible to make the tube part from ABS pipe to save on filament and time ?

Dave

[Gina]

The version above would take nearly 8 hours and 68m of filament to print.  The version below 5.5 hours and 38m of filament (30m less).  Still an overnight print run.

[Gina]

7 minutes ago, Davey-T said:

Hi Gina, would it be possible to make the tube part from ABS pipe to save on filament and time ?

Dave

Probably but I would need to find a source of suitable tube and to carve holes in it - quite a lot of work.  A 1Kg reel of 1.75mm ABS holds 400m.  The filament I'm using cost £4 a reel so 40m of filament cost 40p.  I think a piece of ABS pipe would cost more, particularly with P&P.  I can print big items overnight so time is not an issue either.  I could start a print now but I think I'll print something else.  The printer is very quiet in operation so noise is not a problem.

[Gina]

Just going to print the 45mm lens support ring.  Just over an hour printing time.

[Gina]

I think making a framework/tube that can take all the different lenses could be too difficult.  If I used separate one for each lens the lens support rings could be glued in place.  Anyway, I'll see how it goes - I'll probably make a rig just for one lens to start with.

ATM I'm having a problem working out how to arrange the front support ie. lens end.  This would be assisted by having separate frames.

[Gina]

I've thinned down the framework and the printing time is now just over 7 hours and 55m of filament.  I think I'll make that do and print it overnight.  I could do with seeing how (or if) things will fit together and I could do with some "shut eye"

[Magnus_e]

Hi Gina.

Just need to ask. What filament are you using for this kind of parts?

I was looking at a 3d printer from a local store (flasforge finder). Although it's the most affordable I have found it's very limited in supported materials, and only has a 14cm^3 printing platform.

The Prusa i3 mk2 is not a lot more expensive as a kit, and it can take all 1.75mm filament. http://shop.prusa3d.com/en/3d-printers/59-original-prusa-i3-mk2-kit.html

Are you using a production or home type printer?

[Gina]

1.75mm ABS filament. 

The printer is mostly home made with the frame from a kit.  I've called it my "GinaRep Pilot" as it's RepRap based and my first DIY printer.  See my thread :- GinaRep "Pilot" 3D Printer - Description and Further Enhancements.

[Gina]

The Prusa printer is a well know and popular one.  I believe more than one SGL member has one.

[Gina]

Rotation framework printed fine overnight and I have been trying out how the imaging rig fits inside.  As suspected, the design will need changing to make it work.  Made a mistake with one of the many measurements and the camera wants more ventillation.  Access for the camera connections needs more investigation.

Overall, I think the framework wants printing in two parts which fit together otherwise it will be impossible to fit the imaging rig inside.  I'm thinking of the lens end sliding onto the camera end.  The lens end would have a full circle end for running on a set of wheels on the fixed part.  I have a number of wheels with hard rubber tyres and ball bearings, that I bought for another project but didn't use.

Here are some photos.

[Gina]

New design for back part (camera end).