Barn door tracker plans,build a computer in a desk research,wooden toy puzzles plans - PDF 2016

Barn Door Tracker built with LEGO partsThe recent advent of hack kits for small digital cameras reduces the cost and weight required for entry-level astrophotography. Connecting LEGO parts and non-LEGO structuresI restated the hypothesis as goals and explored how to connect LEGO parts and non-LEGO structures in non-destructive ways.
Motorized crankThe motorized crank is optional and attaches to the bottom of the barn door tracker.
360 degree panoramasThe camera mount from the barn door tracker can be placed on the motorized crank for 360 degree panoramas.
Capture and process imagesThe above image of the Milky Way was captured using this barn door tracker and a low-cost camera hacked with CHDK. NotesUsing the tripod pan head to align the barn door tracker with Polaris while looking through the two sights is manually easy, but it requires visual patience. ReferencesThe center of the 10-32 stainless steel straight rod is located 7.14 inches from the center of the hinge. About the authorI am a maker, hacker, hobbyist, artist, designer, and builder living in the SF Bay Area. At 37 million light years distance, M51 is comfortably the most distant object I’ve tried to photograph. The Whirlpool galaxy appears small in the frame, yet the stacked image above (cropped down from the original) shows a surprising amount of detail. The comet should be visible for most of 2014, as it continues to brighten to a predicted magnitude 6 later in the autumn. Noctilove is a website devoted to low light photography and astrophotography with a barn door tracker.
Almost all images on the noctilove website were taken from a light polluted area of England at sea level. GalleryAstrophotography with a barn door trackerAll images in this gallery were taken with a standard Nikon D7000 mounted on a hand-driven barn door tracker. A Barn Door Tracker mount is an inexpensive and very effective solution for taking long exposures of the night sky without producing star trails.
UPDATED DESIGN: After using the original design with some great results, I recently found some areas where big improvements could be made, including camera placement and laser polar alignment. Using a pivoting drive bolt increases the mount’s accuracy (and tracking time) by around 3-4 times over a regular fixed-position (tangent) drive bolt. The completed pivoting drive bolt can be mounted by drilling a hole (roughly 20mm in diameter) through the top board. A small washer (or small nut) should then be glued on to the bottom board where the dome nut meets the bottom board. The barn door tracker can also be built using an M6 sized drive bolt instead of the M8 size shown.
Many sites recommend using the second hand of an analogue watch to keep time (by mirroring the position of the second hand around the clock face). I realised it’d be easier to take eyesight out of the process by playing a beep at set intervals, indicating when the handle should be at the next point. My first attempt gave some poor results, with the stars forming little circles or semi circles (depending on the exposure length). The camera can be mounted anywhere on the top board, but should have as much room for manoeuvre as possible as it can be tricky to frame subjects. Although not necessary for wide angle shots or shorter exposures, adding a laser or a finder scope to the tracker will increase your polar alignment accuracy over the regular sighting tube (see polar alignment section).
Of the two, I prefer the green laser option as it doesn’t involve grovelling on the floor or contorting your body trying to look through the scope.
For best visibility the laser should be green as most other colours (especially red) will be too difficult to see.
Warning: Although polar alignment will only take a few seconds with the laser method, it’s worth saying that it may make you a bit conspicuous! Many modern lenses don’t have distance scale which makes manual focusing tricky, especially in the dark. If the temperature is much lower outdoors than it is indoors, you should allow 20 minutes or so for your lens to adapt to the new temperature before you focus the lens, as the infinity focus point of lenses changes with temperature. Shooting in RAW maximises the data held in the images, giving much better results with the stacking process.


When you’re out in the dark the images can look overexposed on the camera screen, so I turn the brightness down. The offset of the NCP from Polaris is handily in the direction of the brightest star in Ursa Minor, which can be used as a wide-view guide to make sure you’re aligned in the right direction.
Using a barn door tracker and image processing techniques like stacking can reveal unseen details inthe night sky. The motorized crank uses an EV3 Intelligent Brick, one EV3 Medium Servo Motor, two worm gears, two round gears, and a turntable with 56 teeth. How this was done: I picked a night with a new moon, arrived before sunset, and afterwards aligned the tracker with Polaris by looking through the two sights.
The Virgo supercluster arches overhead in a vast swathe through the constellations of Virgo, Leo, Coma Berenices and Canes Venatici. Despite the huge distance, the galaxy is bright and stands out vividly, even in the individual 30 second sub-photos.
Even some of the nebulous structure surrounding the galaxy is visible, formed by the interaction with its neighbouring galaxy, NGC 5195. In fact it has two tails, the second of which I tried to capture in the 15 minute image stack.
But after looking into the cost of all the components (accurate stepper motor, arduino, motor controller and suitable gears would come to around ?80-100 altogether), along with the complexity of building the circuits, coding the arduino and finding the right gears – you may as well put the money towards a dedicated tracking platform instead! Fortunately any mounts built to the original design can easily be adapted to the new layout. This makes composing much easier and improves the tracking performance through better balance.
For this a 9mm diameter hole should be drilled into the side of the top board to a depth of at least 5cm. Shown below is the simplified solution I arrived at after struggling with a clumsy pivot assembly design described online.
This allows the drive bolt to remain seated in exactly the same place while the handle is rotated. The best option is to use a piano hinge available here which can cover the full width of the boards, be cut to the correct size and so spread the load evenly. In fact an M6 version has the potential to be more accurate than the M8 version due to the finer thread. I always felt this was a bad idea as it’s hard to see the watch in the dark, let alone the second hand! I created an audio file to do this which can be played on a loop via a phone or MP3 player to do its job of time keeping. I used a sample sized sheet of glow in the gark vinyl, which glows for several hours after a second or two under torch light. Placing it nearer to the hinge is advisable as this reduces the load on the handle, and prevents the handle from getting in the way of the camera. It also makes things easier as you can see the entire sky, allowing you to get your bearings and attain a good alignment much quicker. If you don’t have a finder scope bracket for the laser, you can build one by simply drilling a hole lengthways through a column of wood to accommodate the laser with a few mm of room on all sides.
The most accurate method I’ve found is to use live view to zoom in and focus on a star of medium brightness. To prevent this I use PVC insulation tape on the lens to strap the focus ring in place and stop the focus from shifting.
These photos go to prove that you don’t need to spend thousands of pounds on a telescope and an expensive mount. With the laser or finder scope this usually takes less then a minute, but you have to know exactly where the North Celestial Pole (NCP) is (and be able to see it – the stars are pretty faint) to get good alignment.
A barn door moves the camera to follow the apparent motion of stars and sky during long exposures.Given the above, this personal project started as a hypothesis. I didn't know what the final structure would be when I began.The selected aluminum tubing is aesthetically harmonious, is easy to cut with a low-cost hobby saw, is easy to file, is available in avariety of nestable inside and outside diameters, and most importantly fits inside LEGO beam holes and around LEGO axles. The combination of the isosceles geometry and my goal to not modify any LEGO part pushed me to a unique design solution. Tracking seems accurate enough for multiple wide field images taken over a period of several hours.


24, 2014).While building, I realized an isosceles mount would be easy to do and nearly as accurate given the materials and process used here. Many famous and recognisable galaxies occupy this region, but none may be as beautiful as the Whirlpool galaxy. To build up the detail and to reduce noise, images have been 'stacked' with Deep Sky Stacker and processed with Photoshop to make them as pretty as possible. This should be done parallel to the hinge, around 4cm along, as shown in the diagram below (click for larger view).. The main pivot is constructed from an M8 size barrel nut available here which slots into a 12mm hole drilled into the side of the upper board of the mount, making it more robust and accurate. Drilling a second hole (12mm diameter) in the side of the upper board to intersect the larger hole (as pictured) allows the barrel nut to be slid into place, and the drive mechanism to be positioned.
The smaller size hinge also gives less play and greater accuracy of movement compared to something like a door hinge. This is probably the one change which had the biggest impact on accuracy and consistency of shots. With this you can cut out a series of markers, then using a protractor place them around the path of handle at 30 degree intervals (5 seconds on a clock face). The laser or scope can then be adjusted in the bracket until they both point exactly at the same target star. If you don’t have live view, autofocusing on a distant object before the sun sets works well.
This exposure of the Orion Nebula with a 180mm f2.8 lens shows how well the barn door tracker works, even with subjects near the celestial equator. All of the photos in this gallery were taken by me in a light polluted back garden, with a standard SLR camera and the ?10 barn door tracker. The LEGO turntable fits around the hand crank, allowing the barn door crank to travel through the middle of the turntable, while an arm on the outside of the turntable turns the hand crank. One complete turn of the motor moves the turntable by exactly one tooth, so the motor must do 56 full revolutions to move the turntable 360 degrees. Using the side of my finger, I moved the barn door handle to match the second hand position of a clock. You'll find images of comets, meteors, galaxies and nebulae, as well as night landscapes, Aurora, noctilucent clouds, and lightning. Again, I’ve seen lots of trackers online, but none of them seem to have this simple addition. I built three EV3 programs that will move the turntable for 1 minute, 1.5 minutes, and 2 minutes of rotation, all with a 10 second delay to match my camera. The motorized crank gives more time to look at the night sky, but with the addition of cost, motor noise, and batteries. Big thanks to Eric for the extra image processing which helped tease out the finer details. The orange lines on the right side highlight the group of stars which act as a sort of arrow. I highly recommend taking dark frames at regular intervals, writing notes on exposure settings and durations, and occasionally checking Polaris alignment through the sights.
Once home, the DNG images and dark frames were combined to remove noise via Deep Sky Stacker. The handle position should reflect how many seconds have passed during each minute of exposure.
The resulting 32-bit images were further processed with Photoshop CS6 or CC.My phone and camera display were covered with red cellophane.
Using only red light allows our eyes to adjust and see more stars, and avoids disturbing any nearby stargazing. If there are other astrophotographers nearby, be aware that they may be capturing a long exposure and any light from you or your car may disturb them. Be courteous.The Materials and Software link further below includes a list of astronomy, astrophotography, and processing resources I used to plan, capture, and process images.




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