Barn door tracker?

[maceemiller]

Hi all. Hope everybody's OK.

As I have no GOTO mount and my EQ mount is, well, rubbish I'm considering trying to make a barn door tracker for use with my DSLR.

Just after some "real" advice.....I've looked on the net and YouTube, etc and found quite a lot of information yet I'm puzzled by what motor to use. I'm not technically minded with motors and I've gotten confused, probably by over reading!

Has anyone here built one? If so, is there a "simple/simpler " way to make it? Also, is it worth building one!

Thankyou in advance, Carl.

Keep focused!

[ARock]

It might be easier to mount your DSLR on your EQ mount, and give it a shot. It might be terrible for your heavy reflector but fine for your lighter DSLR. That is, if you already have a motor for the EQ mount.

[maceemiller]

I have my camera attached to my EQ and have a Celestron logic motor drive too. Unless it's poor PA I get trails with camera and scope. The mount is very poor to be honest. When I tighten a clutch, even slightly, you can see the mount move, throwing off where the camera/scope was pointed.....it has awful build quality.

This is why I feel it's worth learning more about using/building a barn door.

[ARock]

Did you attach your camera to the telescope? Or used it with a lens (what focal length lens?) on the mount directly? How long of an exposure were you trying? How did you do PA? I have been able to get 10-15 second exposures easily on such a mount with such a motor, with a DSLR and a 80mm F/5 refractor telescope after careful PA.

[Thefatkitty]

I've built one, and it worked well. Problem is my LP, so anything over 20 seconds is kinda blown out....

There is a good article here about doing it manually: Barn Door Tracker. I followed it for myself

Best of luck,

[maceemiller]

The camera is attached to the EQ mount directly with a dovetail. I'm using a lens at 200mm trying for 8 seconds exposure.

PA i did by levelling the tripod and pointing 1 leg South, followed by locking the mount at my LAT (52°).
Line the camera eyepiece finder (no live view on my Canon 350D) up with Polaris in the centre them move camera to target with RA/DEC, tighten clutches, turn on motor, wait 1 or 2 mins then start shooting.......

[Star Dad]

I built a barn door tracker and it works really well for Milky Way/sky shots. I used https://garyseronik.com/?q=node/52 as a guide. Pretty simple actually. You'll need a 9Vdc motor 4RPMs. 2 gears in a 4-1 ratio - to take the 4RPMs of the motor down to 1 RPM. A varistor to allow you to adjust the speed of the motor for more accuracy. 2 hinges (also used for sighting Polaris). and a threaded curved rod. I think the curved rod is essential as I take photos for about 3 hours. You can make do with a straight rod, but your angular motion won't be as accurate. I got the hardware from a local store and bought the electrical parts on line. This is an image I captured last year: https://mcleanresearch.com/astronomy/ga ... _Way_2.png . I'll be glad to help.

[maceemiller]

Great picture!

3 hours!!??!! I can barely get 3 seconds!

Article looks interesting

[ARock]

I think the problem is the 200mm lens for your setup. If you tried a 55mm, it would be a lot easier. If you took pictures close to the meridian, you can tell if your problems are tracking (star trailing in RA) or PA (star trailing in DEC). Keeping the RA tracking accurate with the Celestron motor is tricky too with the tiny potentiometer especially if the battery is not fresh. Look at this video to see how people try to solve this problem.

8 seconds on a 200mm should be possible on your mount with the motor drive if you have better polar alignment and accurate RA tracking. Look at the DARV method for drift alignment. A cruder method would be use your telescope to do drift aligment with a reticle EP first, and then switch the scope with the camera+lens.

Here is a picture I took with a similar mount, with the celestron motor with a 80mm (FL=400mm) refractor and DSLR with 16x30 second exposures stacked and processed. Not all the exposures were good, so I got rid of some before stacking.

[maceemiller]

Thankyou for your reply. I will look into those links.

Here is my effort of the same target at 88 frames all at 1 second each then stacked, processed, etc.

I love your picture. Has soooooo much more detail than mine, hence I need longer exposures.

[ARock]

Good shot !

If you search in astrobin.com there are people using 300mm lens with Barn Door trackers so it is possible. It is also more portable. I have also seen 3D printable Barn Door designs on thingiverse.

I went the other way, mainly because I was using a bigger scope than a camera lens. I finally replaced the Celestron motor drive with arduino+stepper drive, which allowed me to do guiding in RA only. Still takes me quite a while to drift align (I have no view of polaris)

[JayTee]

I tried to build a barn door tracker but I could never find the 1rpm motor the plan called for, so I gave up. Instead, I decided to build one of these, a much simpler project (said with tongue-in-cheek), NOT! But you may find it interesting. I can get up to 3-minute exposures using this setup and the camera lens set to 50mm or lower.
viewtopic.php?f=24&t=3129

Cheers,
JT

[SkyHiker]

I recommend using a small stepper motor and an Arduino. With digital control you can avoid having to use circularly curved screws which simplifies the mechanics. I have built three kinds one of which was dual-axis and autoguided for a 10" Dob. Look on the AF, user Camelhat.

[maceemiller]

I recommend using a small stepper motor and an Arduino. With digital control you can avoid having to use circularly curved screws which simplifies the mechanics. I have built three kinds one of which was dual-axis and autoguided for a 10" Dob. Look on the AF, user Camelhat.

Mmm....just looked at an Arduino and I wouldn't even know where to start? Too many components and zero experience at making circuit boards = Huh???

[yobbo89]

Henk is the expert on diy tracking, I'm sure he and some others could help simplify the explanation and setup of the electronics for you.

[SkyHiker]

Here are some links and documentation, code included. I have better and simpler code now elsewhere, PM me if you want it, but this shows the basic idea.
http://www.astronomyforum.net/atm-diy-t ... ndoor.html
http://www.astronomyforum.net/atm-diy-t ... ation.html
If you are not very software savvy, here's the standard Gary Seronik link
https://garyseronik.com/a-tracking-plat ... otography/

[yobbo89]

henk can we sticky this in the diy corner , i would say it looks like a pretty reasonable /easy project and it might catch the eye of any first time astrophotographers if it was located somewhere in a bit of an easier to find access place. plus it was a good documented post and we should try and save as much good stuff from the old forum.

[maceemiller]

henk can we sticky this in the diy corner , i would say it looks like a pretty reasonable /easy project and it might catch the eye of any first time astrophotographers if it was located somewhere in a bit of an easier to find access place. plus it was a good documented post and we should try and save as much good stuff from the old forum.

Great idea yobbo89

I am definitely a first time astrophotographer when it comes to tracking, etc.

Done planetary webcam video with telescope and sharpcap, got that....

Done 1, maybe 2 second exposures of DSO with DSLR on tripod, got that.....

Stacking, post-processing......I'm getting there but I do understand that longer exposures = better final images, to a point....

....but now I need a little more to satisfy my needs!

As I said earlier in this thread, I honestly believe a lot of my issues are down to a terrible EQ mount... I wont alter on that as unless you've used my "mount" you cant properly understand.

I'm only looking for 10, 15....maybe even 30 second exposures of a given object, MUCH more than I can do now.

Glad I asked this question as already I feel TSS can come up with "a definitive " answer that new and old potential astrophotographers can get their feet on the ground and start walking forward

[Star Dad]

Great picture!

3 hours!!??!! I can barely get 3 seconds!

Article looks interesting

I took 1 minute exposures and stacked them. I probably could have gone with 3 minute - but it was only my second attempt - and I had not processed the first set of pictures, so I had no idea how round the stars would be. Next time I'm at a truly dark sky area I will try longer exposures. I made the tracker mainly to help me get over those nights when we are traveling and it's a clear sky. I hate wasting a good clear night.

Oh, BTW I only used one hinge - not sure why I said 2. Maybe it was 2 screws I was thinking of.

Also be aware that - for me anyways - after three hours the weight of the camera will slide the hinge - opening the hinge very quickly so that the tripod will fail to remain in an upright position. It is imperative to reset the tracker at or before the 3 hours has elapsed.

I am loathe to take exposures longer than 3 minutes because of airplanes and satellites. Their light trails will ruin an exposure - and I'll live with the loss of 3 minutes but 20 minutes? No way.

[Star Dad]

I recommend using a small stepper motor and an Arduino. With digital control you can avoid having to use circularly curved screws which simplifies the mechanics. I have built three kinds one of which was dual-axis and autoguided for a 10" Dob. Look on the AF, user Camelhat.

Please take this with the humor I mean to convey. Only a true geek would say that using an Arduino , a stepper motor, and software can "avoid having to use circularly curved screws ". The screw that took all of 5 minutes to bend to its proper shape. ROFL! I LOVE it SkyHiker!