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Topic: [ASTROPHOTO] Autoguiding using an old webcam and an arduino (Read 1 time) previous topic - next topic

wattevah

Jun 08, 2014, 12:50 pm Last Edit: Jun 08, 2014, 10:18 pm by wattevah Reason: 1
Hi everyone,

Just a quick post here to share a little project I finished this week:

Autoguiding using a webcam an an arduino

So if you know a bit about astrophotography you know about the need to have accurate star tracking. This is often achieved with a seperate camera tracking a "guide-star". As I'm a student and thus have little money, I took a shortcut and built a DIY autoguiding system. I finally got around writing the ASCOM driver for it, so I thought I should share this. As I'm too lazy to maintain a personal website, I'm posting all the info here, who knows, might be helpful to someone  :)

The results are suprisingly good. I was able to achieve 5 minute exposures at 300mm (450mm equivalent for full size sensors) without any trails. I think I'll even go towards 10 minutes next time.  8)

The setup:

  • Arduino nano

  • Polulu stepper driver

  • Wantai stepper motor 0.9° 1.7A

  • Old Eyetoy webcam (playstation 2 game) fitted in a 3D printed case accepting Canon EF lenses

  • Cheap orion eq-1 mount with DIY plate for mounting a DSLR with zoom lens

  • Laptop with PHD guiding 2.2.2



Some pics (click for full size) :



Attached are the .ino code running on the arduino, and the .exe is the installation file for the ASCOM drivers. The C# source code is included, you'll need a tool like MS Visual Studio (express is free) to compile the code.

EDIT: Added the *raw* source code for the ASCOM driver and the STL file for the 3d printed part.

Cheers !
Luca

robtillaart

Hi  Wattevah
Thanks for sharing!

can you share also the source of the ascom driver?

(many people don't like to click on an .exe file)
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

wattevah

You're right about the exe. I added the raw source code. In that case you'll need the create an ASCOM project from scratch and add it manually ! Otherwise just install the .exe and click "install source code".

Luca

robtillaart

Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

dtokez

amazing! looks like epic work, have you got any images to share to show the results?

wattevah

#5
Jun 10, 2014, 09:02 am Last Edit: Jun 10, 2014, 09:03 am by wattevah Reason: 1
Here's a picture of the veil nebula I did the first night I tested the mount:


Canon 1100D, EF 70-300mm lens, f5.6, 4x300s, IS0800. It was just to test the tracking of my mount. More frames and even longer exposures would have given a better result. The lens wasn't focused properly: you can see that the stars in the lower right of the picture are oval even though the stars on the top left are perfectly round. I'll have to double check that next time, hope it is not a lens defect.

I did not have time to shoot more. Hopefully we'll have clear skies this week-end, but I wouldn't count on it. Plus the moon is up.


Luca

vendinleciel

Congratulations for your work

I am new on this forum; i am amateur in astronomy and i live in the north of france.
Arduino is very interseting to make small dyi projects.
Your application for small astronmical mount tracking is very intersting so i should want to realize it with my canon 550d on my eq1.
Can you give me more information aabout the system: wiring between stepper motor and driver controler, and with arduino pins and webcam (schematix picture if possible) and how start  and stop the system.
I try to animate a small group but in north of france the sky is often cloudy!

Have a good day

orly_andico

#7
Oct 14, 2014, 02:02 pm Last Edit: Oct 14, 2014, 02:28 pm by orly_andico Reason: 1
This is very nice work, I am no good at ASCOM drivers so I am re-using the ASCOM driver posted here.

However when using OpenPHD2 2.1.3a I was getting errors "ascom driver failed checking slewing" every time a guide pulse is sent to the mount?!?!? and I have to click the OK button on the error box that pops up.

Apparently a fix was added in OpenPHD 2.3.0 which allows PHD2 to ignore this type of error.  When I upgraded to 2.3.1 the error still pops up but I now can guide.  My challenge now is getting PEC working.

wattevah

Can you give me more information aabout the system: wiring between stepper motor and driver controler, and with arduino pins and webcam (schematix picture if possible) and how start  and stop the system.
Salut ! Je ne suis pas chez moi en ce moment, je ne peux donc pas te donner exactement la schématique du montage. Cependant, tout se trouve sur le net ainsi que dans mon code. Pour les branchements moteur-stepper driver tu peux regarder ici. La webcam est une webcam standard qui se branche via USB. Nimporte laquelle devrait faire l'affaire, a condition qu'elle permette de bien voir les étoiles (éventuellement changer l'objectif, comme je l'ai fait). Le reste du controle se fait avec OpenPHD, il y a des tutoriels sur le net ! Hésite pas si tu as des questions, j'essairai de répondre !

However when using OpenPHD2 2.1.3a I was getting errors "ascom driver failed checking slewing" every time a guide pulse is sent to the mount?!?!? and I have to click the OK button on the error box that pops up.
This is possibly due to my lazyness, I only implemented the PulseGuide functions in the driver. If openPHD tries to slew the mount, it will fail because it will not respond. Do no try to slew the mount within openPHD. FYI I'm using openPHD 2.2.2g.

Apparently a fix was added in OpenPHD 2.3.0 which allows PHD2 to ignore this type of error.  When I upgraded to 2.3.1 the error still pops up but I now can guide.  My challenge now is getting PEC working.
Good luck ! Don't hesitate to ask me stuff if you have any questions !

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