First father/son arduino project. Astrophotography and tracking.

Hello,

I hope someone out there can provide some guidance. This will be my first arduino project and hopefully a great experience for my sons. I want tO engage their passion. For science and building things so they don't lose their motivation and sense of excitement. We've done projects, experiments, and creature collecting in the past. But now I'd like to build something with arduino with them. Myself, I'm not smart and barely graduated high schol. So all of this escapes me. But those boys are so smart, so I want to build an arduino controlled camera mount that can track a fixed point in the night sky.

I've been doing some research, and what I've found that I think may be in the right direction includes: 2x Stepped motors for x/y axis movement, 1x stepped motor controller shield (adafit), 1x Arduino UNO R3, some sort of tracking mechanism, USB cable, appropriate power supply, appropriate drivers/software to send code to the UNO, and the tripod.

I think, for the most part, that I can do this with a little help from you folks. So in regards to the tracking mechanism....how? What could I use to gather informaton on a fixed bright star in the night sky, relay that info to the UNO, that would then send commands to the adafit motor shield telling it where and how fast to move to keep the point centered in the tracking mechanism? Would a camera work? I also saw microwave, infrared...and all sorts of tracking things on Google and amazon. Or would it just be easier to set the motors to, once turned on, step/move at a set speed that matches the movement of the stars in the sky? Lastly, once I get the parts put together and the apparatus built I will seek more guidance on programming.

Also, if I am waaaaay off based here or you folks know a better, more efficient or even cost effective way of doing this I would greatly appreciate it. Thank you in advance and I look forward to working with you all.

Very Respectfully, Evan

Or would it just be easier to set the motors to, once turned on, step/move at a set speed that matches the movement of the stars in the sky?

Yes that is simpler by far. The fixed speed motor will track the sky providing it is on an equatorial mount, set up for your latitude and has been aligned with the polar star.

If you have a randomly aligned alt / azimuth arrangement, then you have to do some complex maths to calculate where to point it to correspond to the right ascension and declination used to denote a star's position. Normally this will involve sighting three stars of known position in order to get the transformation matrix primed. This is something that is done by tracking telescopes these days.

What could I use to gather informaton on a fixed bright star in the night sky,

Not sure what you mean but the position of bright stars in right ascension and declination are available in many star atlases and on line.

Well I'm certainly no expert on the night sky but I would assume you'd need to calculate your local sidereal time. Right off the bat I'm thinking that sounds like some awfully big calculations for a little UNO.

Right off the bat I'm thinking that sounds like some awfully big calculations for a little UNO.

No calculating the local sidereal time is very easy and well within the capability of an arduino.

Grumpy_Mike: No calculating the local sidereal time is very easy and well within the capability of an arduino.

Ah, very good. I wasn't at all sure (still am not) how much approximation one can get away with before pointing the telescope and missing.

how much approximation one can get away with before pointing the telescope and missing.

It depends on how wide your field of view. The right ascension is basically the sidereal time and is measured in hours, minuets and seconds. A sidereal day is 23 hours, 56 minutes, 4.0916 seconds so very close to real time.

Did you ever play with an open source program called Stellarium. Download buttons are on top of this page. Telescope control is on the feature list. Don't know how/if that part works. Leo..

Yes I have seen stellarium, it just sends the celestial co ordnates to the telescope controller. The controller still needs to work out how to move the scope to get to those co ordnates.

For accurate polar alignment you really need to point to the Celestial Pole, not Polaris, but Polaris is close enough in most non-telescopic uses. If you get star trails, then go for the Pole, not the Pole Star. To find the Celestial Pole, Locate Polaris (North Star) and Kochab (bright star across the bucket, where the handle meets the bucket, at Akhfa al Farkadain). Draw an imaginary line from Farkadain to about 1.5 degrees past Polaris. That point 1.5 degrees past Polaris is a close approximation of the present Celestial Pole.

OP, Search 'Barn door mount'. By a decent DSLR camera (Nikons work, Canons are better for Astrophotogs) with a low F-Stop lense. Fun hobby. They'll LOVE it!

If you Polar Align correctly, you don't need to worry about your imager coordinates, just point and shoot. A planetarium program for your PC is a great tool to decide what to point at.

If you get star trails, then go for the Pole, not the Pole Star. To find the Celestial Pole, Locate Polaris (North Star) and Kochab (bright star across the bucket, where the handle meets the bucket, at Akhfa al Farkadain). Draw an imaginary line from Farkadain to about 1.5 degrees past Polaris. That point 1.5 degrees past Polaris is a close approximation of the present Celestial Pole.

Very inaccurate. On my scope you go for the pole star, the finder graticule has a circle round it sub divided into segments. You make sure that the pole star is aligned in the segment of the circle that corresponds to the current sidereal time. No close approximation but spot on. However, for just a simple wide field camera tracking stars the pole star will do just fine for the next couple of hundred years.