quad multi lens imaging camera

[DIYASTRO]

Hi Mick, Thanks for kind comments and thanks to those who posted 'likes'... nice to know that others are interested in the project.

Will not be using the remote control.... they are not specific to each board so if you have  several 'open' to the command from remote they all start working!

The thread on R/C servo conversion is indeed a swop for stepper motors. I scoured Ebay and lots of suppliers for motors small enough. Could not find any at the exact diameter etc which is why you will see that a 'locating ring' has been turned on the lathe to locate the new motor centrally so that the gear's mesh correctly. I had a look to see if the supplier I got mine from still has them but alas, sold out. Will keep an eye on that in case he gets more for sale but needless to say they came from China!  I think the R/C conversion is worth the effort to obtain the high level of torque but have to admit, it is a real fiddle. I have done around seven of them so far and they take ages but you do end up with a powerful yet small drive system that can be stepped. 

Boyd

[Ajohn]

I wasn't clear on the servo or stepper motors Boyd. I got the impression you were going to replace the servo's with small stepping motors. As you know I'm curious about the servo approach as well so wonder if they have problems and if you have replaced them.

Must admit I'm thinking in terms of using servo's in the normal configuration -- an arm that swings through circa 90 degrees rather than converting them to rotate or buying that type which are bit thin on the ground.

John

-

[DIYASTRO]

John,

Have a look at my thread on page 2 of this section   ' R/C servo stepper motor conversion'   and all will be clear!

Boyd

[Ajohn]

Ahhhhhhhh I see you have swapped the motor. Personally I hope the servo arrangement normally in them is stable enough.   Some one has used the continuous rotating type where the mark space ratio sets the speed they turn at.  Not sure I fancy that option as the servo positioning aspect is lost.

John

-

[DIYASTRO]

Ajohn,Glad you had a closer look at the servos, all should be clear now.

Still awaiting delivery of push to make switches but have been able to test the focus drive systems on the crayfords by wiring in a temporary wiring loom on the rear plate of the rig.  The control panel with the stepper motor drivers is connected via a 25pin D 5 meter cable. This uses 20 of the connections for the five focus servos leaving a spare five connections for the camera 'trigger circuit'.

I have been working on the method for the timed camera operation.

You will see from the second pic, I have designed a circuit board which accepts the timed sequence from a standard EOS timer. The 'pulse' from the timer goes to four separate 'Schmitt triggers' (avoiding spurious signals) these triggers in turn power a transistor switch which then powers a set of four relays from which the n/o contacts provide the 'trigger' to the cameras.  I may at a latter date use a set of led indicator terminals from the transistor switch to provide the option of opto isolators to do the camera shutter. 

I posted a question in the 'camera' section earlier today. I am trying to work out if it is possible to switch the camera on and leave that switch in the on position and simply using an on / off switch to the cameras battery / power supply. Has anyone tried to do this??, if so does it cause any malfunction issues at all?

Boyd

[Xplode]

Leaving the cameras on is no problem and turning on the power is like turning the camera switch.

I use the same method on my 6D and it works fine except that i have to push a button on the camera since my battery adapter is not recognized as a genuine battery. Not a problem you will encounter with your cameras since there is no stored information in batteries on cheaper cameras.

[DIYASTRO]

Xplode,

Thank you for your post in answer to my question, that is very helpful.

Makes it somewhat easier to operate remotely as intended.

Will make a start on the power supply module for the 4 Canon cameras this afternoon if I can! I have two of the 'imitation' batteries and leads already.. need to make up a couple more and should be ready to wire it all up and try an image or two!

Thanks again.

Boyd

[DIYASTRO]

Thanks to those who gave nice positive reply to my question on Canon switch on/ off dilemma, I have the confidence to proceed with the next control panel. 

You will see from the  pic of it that the power on with led indicator provides the on / off function for the cameras.

I also have provided a toggle switch to eliminate any camera from the timer circuit. I may only want to use for example, 3 of the four cameras for an image, this allows for any unused lens / camera to be 're-routed' to perhaps another small screen for maybe a large finder scope.

I have also placed led's to indicate if the particular camera has been selected or / and imaging via the timer circuit.

Hope to get it all wired up very soon, looking forward to trying it all out!

Boyd

[Mick J]

"looking forward to trying it all out!"

Looking forward to seeing that happen,  so all four cameras are on the same trigger, same exposure time, do you plan to add more timer remotes Boyd ?

[DIYASTRO]

Firstly, Thanks to Psychobilly for his help on another thread relative to the Canon on / off problem and your likes post was much appreciated.

Mick,

I should have perhaps explained my last couple of posts better! The 'off the shelf' programmable timer plugs into the circuit which I described as having 'Schmitt triggers' this enables, by selection from the second panel, either one, two, three, or all four cameras to be activated at the same time and for the same period.

No other timers needed.

For some targets I may not need all four cameras to be used so I have allowed for whatever is not required to be 'omitted' from the timer sequence. This provides an opportunity for on the 100mm diameter f4 lenses to be used as a finder scope perhaps. 

The idea with this rig is to capture at the same time for the same period identical images albeit using Ha, Hb, 0III & SII filters, one for each camera. ( or of course, no filters at all thus creating 4x the length of exposure) These images are then processed and 'imposed' on each other to provide what is hoped are superior ones than those taken over long period of time separately.

I debated long over the question of either 3 or 4 cameras / lenses for this rig.

I chose 4... the main reason....... I think that some targets may benefit from using two different wavelengths of Ha filtration...(Example 35nm 12nm 6nm)  So by omitting perhaps Hb and substituting for different Ha wavelength I ????MAY???? get better results!

This was one other reason why I wanted to be able to 'isolate' a specific camera from the timer sequence, this allows , if required, a shorter exposure for any camera without interrupting any other. That may be useful when trying say, a 35nm and 6nm  on different cameras on the same target.

Gets a bit complex after that...so much so that I am not sure I understand it either! but you will get the idea .

Boyd

[DIYASTRO]

Thanks Ajohn and MickJ for your likes posts!

Still no switches from Maplin, hope they arrive soon.

Have been busy with the wiring up of the circuit boards and control panels.

Very untidy but no point in tying them neatly until the other switches arrive and are soldered in.

This has allowed me to test and confirm that I can now power up cameras and switch them off again remotely. 

I can now also isolate any camera from the programmed timer sequence and have nice visual conformation from the various led's that things are doing what they are supposed to be.

I did get some nice cables etc from another source today, 2.5 angled stereo jack leads for the timer circuit to be plugged into the cameras and also 3.5 angled mono for the video out from the cameras which go to the colour quad processor then to the lcd screen.

Hope  get some more wiring done soon and then design and make the console to become operational!

Boyd

[DIYASTRO]

Finally received my 6 switches this morning so promptly red then into the control panel! 

Tidied up the wiring loom a little and have just tested it out on the focus / crayfords and all looking good. 

Also got some new mini stepper motors so should now be able to remove the small dc servo which controls the focus for the guidescope and provide a stepper motor / gearbox for smoother and more accurate focusing.

Just wish I had more time. Moving house in few weeks has just scuppered advance with the build!

Thinking all the time whilst packing boxes how to design the console for the control panels / electronic circuits , etc.

Also thinking about the requirement for dew heaters around the five lenses!

Boyd

[DIYASTRO]

Its been a niggle all day.... I know I have to change the small servo dc motor that actuates the focus for the guide system, so I have stripped down to access the focus unit and thought some of the photos where interesting since they look like rocket exhausts! 

The first pic is the front of the camera with the objectives removed except the guide scope.

Second pic is front plate removed to reveal the guidescope focusing unit

Third pic is the guidescope focus unit removed.

forth pic is the detached guidescope focus unit with the dc servo originally used for initial trials but was  unhappy with it!

fifth etc is this unit being de-assembled ready for a new stepper drive which will be smoother and more accurate.

Boyd

[DIYASTRO]

Thanks to Gina & Mickj for the likes posts.

Managed to re-assemble the guidescope focus unit with its new stepper motor gearbox.

essentially the focuser is a stripped down slr lens helical section.

I have fitted a gear .5 mod 190 tooth gear to the barrel and this is meshed with the new drive gearbox which now has a 14 tooth .5 mod gear attached to it.

This gives a ratio of 13.5714 :1.

I ran this late last night to ascertain the 'values' of helical movement for selected drive speeds delivered from the stepper motor control.

At speed 9 (fastest speed) I get a linear forward / reverse movement of 1.0275 mm  / sec.

At speed 5 ( drivers default speed) I get Movement of .1241mm / sec

At speed 2  I get .0226mm / sec

At speed 0 ( slowest speed) I get .0058 m/ sec

The slowest speed roughly equates to about 2 thou/ sec in old money, which is good enough for guiding purposes.

Have refitted the unit within the rig and all working very well.

Couple of pics to show the new drive motor, of course from China! Stripped it down before fitting and the quality of the gearbox is excellent so I have ordered a couple more. By the way it doesn't come with the 14 tooth gear, that was from other supply.

Boyd

[DIYASTRO]

Begun to wire in the various connections to the cameras and Crayford's.

You will see that I have used a 2" ali angle 'bracket' which will hold all the cable connections for the rigs operation.

The 25 pin D is the connections for the Crayford focusers and also carries the trigger signal from the timer circuit to the cameras.

The small abs black box has the plug / socket fitted for the angled jacks for camera' triggers' and will also take the four BNC video connections.

I will fit another of these ABS boxes to the other side of the 25 pin D skt for the camera power up connections.

Coming on, albeit slowly!

Boyd

[Ajohn]

 I'm wondering when some one will do a quad 6in F6 newtonian.

Could you tell us where the steppers and gears come from Boyd, say an ebay number if any came off there?

John

-

[DIYASTRO]

Hi Ajohn,

Thanks for your Likes post.

Actually... I pondered the idea many years ago of doing a triple or quad 8" reflector with small webcams or other small cameras positioned at prime focus doing away with the secondary's altogether. Its not just the cost of such a build its also the shear mass of the scope that stopped me! Somehow, you have to mount the whole thing and since I am obsessed with fork mounts the forks required would be quite large indeed!

I will have a look just now and see where I got the steppers and gearbox and send you PM.

Boyd

[Ajohn]

 Bit off topic to the thread but it struck me that people put up with long exposures on refractors with relatively small apertures but no signs of the use of smaller sizes of reflector. People tend to go big and short focus for photo/visual use but that brings down the maximum field angle that will have more or less round stars. Against that people pay a lot our for a 5 or 6in  F6 APO.

I agree 100% about fork mounts - No counterweight, a big advantage.

John

-

[DIYASTRO]

Hi Ajohn,

The wonderful thing about forks is that you don't have the problems of 'meridian flip' They go though their motions smoothly and capable of large loads.

They also have the advantage when doing visual stuff of not having to contort to see through an EP!

Been working on the 'feed' cabling and electronic connections required for the link from console to mount / cameras. Lots of soldering and cable connections, I think its worth the effort though.

Will post some new pics in a day or so, had to order in quite a bit of stuff today to get it all connected, amazing how your supplies dwindle when you are basically repeating things four or five times as is the case with multi systems.

Boyd

[DIYASTRO]

Spent what little time this evening making up cables for the connections from console to mount.

One thing that bothers me, connected with my last question on powering up canon 1000d via battery / power supply.

Does anyone in astro land know just exactly how much power (current, amps) is required for a 1000d to function with mirror locked and creating timed exposure? I suspect it is less than 1 amp but not too sure so if anyone has done the test with ammeter would be grateful for the result.

My test equipment, well most of it, is all packed away in boxes!

Boyd

[DIYASTRO]

Thanks to Ajohn and Chinapig for the likes posts.

Been busy with lots of non astro stuff but have managed to produce a few of the cables required and one or two of the circuit boards.

I decided to power up my four canon 1000d' via the power supply / battery connection. However, I don't like the idea of the 'Pseudo' battery which most people simply put a voltage regulator  in place of the cells within the battery housing.

I have gone for a power supply from the console via a bank of voltage regulators direct to the camera, still using the battery housing for the contacts, in an attempt to cut down on any extra heat generation from the cell. Probably isn't much if anything at all but just seemed a good idea.

Also made up the voltage regulation power supply for the stepper motor controllers, which will also be contained within the control console.

I mentioned that I may alter the camera trigger from relay n/o contacts to opto isolated trigger from the timer circuit, well I think that may be good so made one of those up too.

Have nearly completed the basic structure of the console, still a little way to go with that.

Just wish that some of the essential supplies that I have ordered to finish this off would arrive soon! 

You can see from the pic.

Far left is the power module for the four Canon 1000d cameras

Second left is the power module for the 5 stepper motor controllers for the focus

Third opto isolator and extra relay circuit for camera trigger (and other)

Fourth, this is the other box that fits on the angle bracket and will supply the power to the 'pseudo' battery / power up for the four cameras. 

Boyd

[DIYASTRO]

Thank you Horwig for your likes post.

I have been quite busy on the casing for the control console, I will post some images of this when it has reached the stage of having the electronics and its wiring looms in place.

Just about finalised the camera connections on the rear of the rig. 

You will see from the pic that the 4 video outputs (BNC) on the left will be connected to the quad processor which will give the four separate images on the flat LCD screen. The quad processor also enables the whole screen to become available to any one of the four cameras which will help with the visual focusing.

The four DC skts/ jacks on the right are, as can be seen, feeding the 'false' battery which will power the cameras.

The centre 25 pin D skt is connected to the console and controls the five focus stepper motors and also connections to the timer / camera trigger.

I have yet to get a 5/6 port usb hub which will be mounted just above the 25 pin d skt and enable, if required, any future pc control for the cameras via for example eos utilities.

Just need some more time from somewhere to get it all finished!

I finally took the courage and purchased another Canon 1000d ! The 'empty' Crayford focuser for the fourth position on the rear of the rig looked wrong!

Boyd

[Mick J]

That's outstanding Boyd, neat and tidy, hope you have a nice spot for it when you move.

[Gina]

Certainly an awsome piece of kit - that's for sure

[Horwig]

IT's a pleasure to see nicely laid out veroboard Boyd.

I'm with you 100% on forks, why did GEMs ever take off, forks are so much more elegant, here's mine:

BTW, that would carry a quad 8 inch array.

Keep up the good work

Huw