DIY-ATM Project Stories
This is another page that will always be under construction.
Dobsonians and Newtonians
Afocal Adapter for Cell Phone
Mounts and Tripods
Parallelogram Binocular Mount
By Steve Boerner Back in the 1980s I got a pair of Orion 11x80 binoculars as a present. I never used them much because at more than 5 pounds they were too heavy to hold for more than a few minutes. A few years ago I made a look down binocular mount for them but all too often the mirror would dew up after only a short use. After ASEM.started a DIY Special Interest Group (SIG) and I decided to make a Parallelogram Mount from discussion within this group. The mount is constructed out of sections of 1"x2" oak. The mount sits on top of a tripod and is connected to the tripod with a Bogan hexagonal quick mount plate...see my personal (member page) for more information and pictures.
Barn Door Mounts
By Marv Stewart
Thane Bopp, an ASEM member, at one time made Barndoor trackers as a project for a class. Thane passed out the plans and looking at them I started taking a mental inventory of the material needed to build one that I already had laying around my workbench. I had a piece of scrap wood that was free of knots. I had a brass door hinge, and the required basic tools. At the hardware store I bought a few more needed items: a 1/4X20 T nut ( Pack of 4, you need three,) a 4 inch 1/4X20 eyebolt and a cap nut, for a total additional investment of $1.89. I took my time, and in a couple of hours I had my tracker. Some assembly notes: The hardest part is the measurement from the hinge to the hole for the eye bolt is critical, if its wrong the tracker won't work properly. I checked several times, the distance from the center of the hinge to the center of the eye bolt is 11 7/16 inches. It might be easier if you converted this to metric and measure it off as 29.0 cm (see math below). I found using a rubberband on the open end provided just enough tension to make the screw turn smoother. I attached a peanut butter screw cap to the turning bolt and that also made turning smoother (check that out). Near the hinge is a tube I use to find the North Star to help align the tracker. And instead of making a mount for the camera (Thane's barndoor design included instructions on a mount), I chose to use a purchased mount from my camera kit.
An external timer is very convenient to have and necessary to monitor long exposures. I found a nice low cost digital one at a Dollar store, that is shown on the top board. While it worked fine for keeping time, it was impossible to read its digital numbers in the dark (no backlight), and using a red flashlight to read it risked ruining the exposure. So if you pick one of these up, I recommend locating it in your pocket or somewhere away from the camera. Still useful to have though.
The Barn door tracker was born in the late '80's, long before digital cameras. This barndoor mount tracker will give one an accurate exposure of about 20 to 30 minutes. I feel that since digital cameras are more sensitive that exposure time should be shorter and results better... My un proven opinion at this point. Marv
Barn door math:
1 sidereal day = 23.9344696 hours or 1436.068176 seconds
using a 1/4"x20 thread gives .05000" lift/second (1/20) so
1436.068176 seconds * .05000 inches/second gives 71.8034088 inches travel/day (circumference of disc)
dividing by 2 pi gives a radius of 11.42820 inches or 29.03 cm
Hand-Controller Soft-Touch Attachment
By Grant Martin
I needed to get away from Velcro for holding my hand controller to my scope. The glue kept coming loose and all convenient surfaces needed to have a mating piece of Velcro. One small length of loop Velcro on the controller needed a very large length of hooks all over the scope. Since nearly all of the components of the tripod and OTA are steel, magnets sounded like a good solution. Putting magnets on the controller will allow the hand controller to be placed on any convenient surface of the tripod or OTA. Solution and details, with pictures, on this page
Built by Eddie Agha The Power Pack has both a deep marine battery for running my CGEM mount and cameras, and a charger, that is mounted on top of the battery box, for travel, making it a "Power System." This way you can run your mount & charge the battery at the same time if you have AC power. Check out my page on this project (for photos and BOM).
For a Large Dob
A home-made "Cats Perch" type chair by Marv Stewart