I will have a lot of fun building my homemade 12.5 inch Dobsonian Telescope!!! Start with the small components first. 1" Rack & Pinion Focuser. Drawing lines between opposite corners of the tube box sides allowed me to locate the center point on each side. needle so the knitting needle will be snug against the drawtube without The mount and tripod are pretty much useless for astrophotography. Not sure if it is available in the USA. I had considered using a clear finish alone, but decided to use a dark red finish on the base and a clear finish on the tube, just because I like the look. Be creative! try { but try for a snug fit if you can. We then spread contact cement over the remaining veneer and tube surface, waited for the glue to dry, and carefully rolled the tube over the veneer. Once you get it working, there's some calibration you need to do. I marked the expected position of the secondary by measuring 61 inches down from the end of the tube. Nice looking telescope. Two inch internal diameter drawtube. Here is a simple 3D printed helical focuser that cost just a few cents (assuming you have a 3D printer). The arc at the top of the sides needed to have a radius 1/8 inch larger than that of the side bearings to account for the thickness of the teflon pads that would fit between. can't click on it or copy and paste it; it's a graphic file to thwart But let me see what items I can arrange to make a helical. It was easy enough to drill a hole and tap threads for a We tried this in our back yard, but found that it was too difficult to aim both the tube and the moving mirror at distant trees in our suburban yard. Participated in the Celestron Space Challenge. Some quick tips to note if you are making a homemade telescope are: 1. To make the hole for the focuser, I used the focuser tube to mark a circle in the shroud. The core of the telescope, the steel mirror cell holds and adjusts the heavy, curved primary mirror. knitting needle where it goes through the hole, so it's not a big deal, As the authors describe the benefits of a truss design, it is hard to dispute their arguments. My guess is that photo was taken with a refractor. how much travel you actually need, you can cut the tube off so none of The shroud made from two 22 inch tall containers came out short, so I had to add an eleven inch strip of nylon. And the legs of the base should be as wide as possible to accommodate weight imbalance as the telescope is moved around, to avoid tipping. You should now be able to drill the 4 holes at each corner. think that design would be rigid enough under the weight of a diagonal Using a compass I drew circles on the top and bottom of the ground board to mark the inside and outside of the teflon ring on the bottom of the rocker bottom. If not, you may need to design and print your own bracket(s), gears, and so on. The bigger upvc nut will be attached to focuser plate and longer threaded side will be used on it for the focusing. Inside the OTA is a ring of tightly fitting flocking paper that prevents any light getting in around the drawtube. Download and unzip. To view, go here: http://emediadesigns.com/focuser/ They eyepiece height ended up being about 5'10" high at zenith. Building Your Second Homemade Telescope - Part 1 - HubPages A Pocket Sundial From a Broken Pocket Watch! As the telescope tilts toward the horizon, the mirror must be supported on its edge. I was inspired to build telescopes during a trip out to McDonald Observatory in west Texas, where I saw a 36 fork-mounted telescope, tiny in comparison to the huge research telescopes at the site. This allowed me to cut perfect identical circles. The side bearings are each made from 2 identical semicircles of 5/8 inch plywood glued together to make a thickness of 1 inches. There are a number of technical reasons why these photographs could not have come from this Optical Tube Assembly. After a dry fit of the rocker to make sure that the tube box with side bearings would fit well, I glued the rocker sides to the rocker front, holding them in place with small nails and clamping overnight. See above, this motor does not produce a lot of torque, but you don't need much for this application since there is no 'load' on the focusing shaft. Meade Zero Image-Shift Electronic Micro-Focuser This high precision focuser allows you to obtain an extremely accurate image focus. When you figure out Slide the eyepiece into the focuser and try it out. I carefully cut exactly through the center of each side bearing circle to make my semicircles. It features 2 semicircular arms, and mounting points for the trusses (T-nuts are fine), as well as a lid to keep the mirror safe when the telescope is not in use. Before I wrapped the tube (and before I discovered the problem with the primary placement) I determined the balance point on the tube. I ground and figured the mirror with little troubles, making my focault tester, etc. It took about 3 weeks but, since Anttler's did not even reply to the Paypal dispute, I received a Paypal refund. the side of a rigid secondary cage. Only problem is if I put a diagonal it wants to rotate the helical part. We were careful to press out any bubbles as we went, but when the job was done we found that there were multiple bubbles in the veneer. I did run into a small problem with the focuser. exactly 2" with adhesive labels placed one at a time inside the tube His passion is using CAD design and his homemade CNC router to bring large wood projects to life. off the bearings. This focuser (see pic at bottom) was motorised by me several years ago, but the motorised system didn't give me very fine control, and the motor running at fast speed tended to make the Artemis camera crash. I found out pretty quickly that building my own telescope would only be a bargain if I made my own mirror and mechanical parts. Next, attach the eyepiece and the focuser to the top part of the telescope tube. It's easy to shim it to I will get good 30-40 mm focusing range. Link to the motor speed controller kit:http://www.jaycar.com.au/productView.asp?ID=KC5225(a 5K external potentiometer will be required): http://www.jaycar.com.au/productView.asp?ID=RP3508The drive motor:http://www.jaycar.com.au/productView.asp?ID=YG2734The gears:http://www.jaycar.com.au/productView.asp?ID=YG2736The motor forward/reverse switch:http://www.jaycar.com.au/productView.asp?ID=ST0506The push button:http://www.jaycar.com.au/productView.asp?ID=SP0711 on Step 5, After much debit and doubt i have taken the photos down cause i cannot be 100% sure that they were taking from my scope as i was not there to verify them and i do not want my contest entry to be based on photos and not the build process. Also, I will work with my computer geek buddies, so that we eventually automate it using Linux on a Rock64, to run kstars for tracking, on INDI. They're fairly guarantee a response, but I'll do my best to answer everyone who writes To get a slide-fit in a 3D printed part, you normally make the hole 0.5mm larger than the shaft. And for those who like to work with 3D printers, both the single speed and dual-speed versions could easily be printed. I had the thought that as long as I was going to build it I should build it as big as I could afford. If you wanted to really go low-profile with this design, by cranking Line the underside of the rocker box with a ring of ABS plastic to allow it to ride on the base. A neet site: http://www.astropix.com/HTML/I_ASTROP/CAMERAS.HTM Cool instructable, Dude! help eliminate slippage when the focuser is pointed straight upward. A celebration of the Maker Movement, a family-friendly showcase of invention and creativity that gathers It stalled when tension on the belt increased. The 48 inch width of the veneer was close enough to the diameter of the tube that I used it as is. With the DRV8825 and Arduino Nano plugged in, the basic board is complete. Above youll find an interactive 3D rendering of the Sketchup file I used to design and cut all of the parts for my telescope. : "http://www. I installed the spider first, about one inch down from the end of the square end of the tube. var gaJsHost = (("https:" == document.location.protocol) ? The mirror itself must also be able to tilt in three dimensions in order to aim its light at the secondary mirror (a process called collimation). A week later the cell arrived (on schedule) from University Optics. Able to make myself using my own humble tools (or toys as the pros will call them!) These are mounted 120 degrees apart and use 4 inexpensive bearings to support the tube. In my build, the cage was cut on a CNC router from plywood, with threaded T-nuts added to support a truss assembly. I file a dispute with Paypal to begin the process of getting my money back. The secondary holder is adjustable, so I could didn't have to get the location perfect. Focuser minimum height is 50 mm and maximum a little over 90 mm so it is good overall. Nice work and great instructable! Your astrophotographer friend may have included his own images from his setup. The project creator Robert Brown made a good video on testing the board. Several clamps were used to hold the pieces together overnight. Unfortunately I don't have a 3d printer. An Altitude Azimuth mount would also require a field rotator.There's no way these were taken with an Orion GoTo Mount. I want to make this direct drive system work. homemade Crayford focuser. Sonotube (14 inch diameter, 12 feet long): $70, Focuser (GSO 2 speed low profile Crayford): $139, Total cost for supplies for this project: $1700. In order to check your measurements, you can construct jigs for your mirror cell and secondary cage, positioning them on a straight, adjustable track such as 2 planks of wood. The base of the telescope should be a wide, sturdy square or circle of wood with teflon bearing pads matched to the ABS plastic ring of the rocker box. I wanted a tight / press fit, so I only added half that, 0.25mm. This is my copy of the telescope that Sir Isaac Newton presented to the Royal Society of London in 1671, and is considered to be the first successful reflecting telescope. Before you do this, the stepper motor will probably move, but it will make a 'stuttering' sound instead of moving smoothly. The arc at the top of the sides needed to have a radius 1/8 inch larger than that of the side bearings to account for the thickness of the teflon pads that would fit between. During assembly, youll attach the trusses to the mirror box, then sit the secondary cage on top and bolt everything in place. The dimensions of the Tube Box Sides are based on the outer diameter of my tube14 3/16. I made a similar helical focuser with a nice 2 inch thing I found in Classifieds. Read the documentation though, there are a lot of functions and options. So, for my telescope I used a 6mm to 5mm coupler available on Amazon. focuser. I sanded all parts of the telescope with 220 grit sandpaper followed by 400 grit, making a very smooth surface to apply the stain. A 6 in primary mirror does not have enough weight to make the dob stable. We are now ready for some testing. I had to take apart the focuser in order to get my bolts in place. You need some purple bits you could probably space the bearings 3/4" apart instead of 1" and mount . This combination has proved to be effective for all positions except when the tube is pointed directly up. The drawings are only approximately to scale. It took a lot longer than I expected to receive my mirror and other parts from Discovery. 11 years ago You need a drawtube of course. An electronic focuser, which moves the focus knob through a combination of hardware and software, solves this problem. a try. I decided to keep this tube for now and if I run into problems with it, I can replace it later.
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