A 3D printed Bahtinov focusing mask for a Televue 76mm telescope
For this mask I used a public bit of OpenSCAD code from Jens Scheidtmann to generate the mask pattern, just tuning it for the correct sizing and performance with the TV-76. I added my own version of the support collar, making it a bit neater with fillets and properly sized to slip over the TV-76 glare shield.
The part is one of a half dozen parts I have designed and printed over the last few weeks to reassemble the photo rig. A new guide camera mount, a mount for the ASI Air computer, a new glare shield for the guider, etc., etc… The utility of 3D printing a game changer for me.
Over the last week at work we have been preparing an unused part of the facility for use. We need a place for an industrial freeze dryer and a walk in cooler. But first we had to clear out a massive pile of junk that had accumulated, and do demolition on a lot of old equipment and piping to remodel the space.
A burned and melted power receptacle
Demolition? Break out the sawzall! We used a big sawzall, a small pile of saw blades, an angle grinder with a diamond cutoff wheel, a bit of muscle and a lot of sweat to get it done. The pile of trash accumulated rapidly along the fence, old lumber, a lot of PVC pipe, and a lot of rust… A big dumpster will appear later.
Rust. This close to the ocean everything is badly corroded, do not even try to release the old bolts, just pop a fresh battery into the angle grinder and let the sparks fly. The 20 amp sawzall does not use batteries, good for the thicker pipes and framed walls, it rips through PVC like butter.
A couple weeks ago at the volcano I let quite a few folks take imagery of the lava using the afocal technique, simply holding the phone up to the eyepiece. This works rather well as the phone uses a lens much like the human eye, about the same aperture.
Shooting afocal with an iPhone and the TV-76mm ‘scope
The only real issue is holding a phone in just the right spot. Folks wanted video, but holding the phone steady is a real challenge. I had thought of making something to do this many times, last weekend I did it.
A session of playing around in 3D CAD resulting in a couple bits of clever plastic printed with the 3D printer… Done.
There are commercial solutions for this available, quite a few actually. But most of these are intended to adapt to a single phone, using some sort of clamping arrangement that you have to setup for a particular phone. I envisioned something that was more universal, quickly adapting to any phone.
The method I chose was a sliding magnetic platform that holds the phone. Just a simple shelf actually, set the phone on it and slide until you get it lined up. The base piece is printed with a recess into which a steel plate is set. The slider has three 8mm x 2mm neodymium magnets to securely grab the steel plate.
It took a bit of work to cut and file the steel plate to neatly fit the base, a bit of inlay work. Otherwise making the piece is quite easy. The only design issue is that this adapter is setup to fit a single eyepiece, a Televue Panoptic 27mm, and cannot be easily adapted to others.
The 3D CAD files are linked below. I have included the SCAD source file to allow tinkering with the design, possibly adapting to a different eyepiece. Both parts should be printed with support on, the pockets for the glued bits will have to be cleaned out, the resulting rough surfaces just right to recieve epoxy.
At the Keanakakoʻi Overlook I was able to test the adapter with a variety of different phones, both iPhone and Android, graciously lent to me for my experimentation. OK, the owners may have wanted a few lava photos. There was no difficulty using the adapter other than a moment or two needed to line up the camera with the exit pupil of the eyepiece. The result was more than a few smiles.
In the back of a plastic crate, forgotten for a decade or three, a little cardboard pack holds a few battery holders. A humble package, not containing anything particularly special, yet this is a time capsule from another age, another me from decades ago.
A set of battery holders in retro packaging
This little package brings back memories… I remember when shelf after shelf of components were packaged this way. The look, the smell, the facination with the fantastic array of parts on display in those little packs, each inspriation for a project or solution. The young teenage me wandering those shelves wondering what I could do with those components.
Continuing in my 3D printing bender I have been finishing up a few projects that have been on hold due to missing bits. A few other prints have been done to improve the printer itself. While along the way there have been a couple things designed and printed just for fun.
Minimalist 3D Printed Lamp
I needed a lamp to keep the 3D printer bed illuminated without leaving all of the garage lights on. This light would allowed me to keep an eye on long prints using one of the little Wyze security cameras.
A bright LED supplied by the 24V power supply of the printer would be just the thing.
I wanted a smaller, lighter finder ‘scope for the Astrola, and I wanted right angle to stop straining my neck!
3D model of the 40mm finder designed in OpenSCAD
I have been using a big Orion 9x60mm finder on the Astrola, the only telescopic finder ‘scope I have among the Telrads. It is nice, with a bright image that shows many faint fuzzies. It is also huge, and very heavy, it is also straight through, requiring one to crane your neck around to view through it on the Newtonian ‘scope.
The Creality Ender 6 is an impressive 3D printer, particularly for the price. It does exhibit some obvious design issues however. One of these is the hot end cable clamp, it is just not sized well. This critical cable harness flexes constantly as the hot end moves back and forth.
The Ender 6 hot end cable clamp as supplied
The supplied clamp is one of the few 3D printed parts on the Ender 6. As you can see from the photo the clamp is simply not large enough to properly secure the cable loom. This is odd, as it would have been so simple to design and print a properly designed part.
Can you leave the clamp like this? Some hackers do, I have seen several YouTube videos of well used Ender 6’s with the original cable clamp and loose wiring. It does work, I printed my first prints with the clamp like this. However, if left alone it is likely that the wires would be stressed over time leading to premature failure of the cabling and requiring an annoying repair effort.
For much of the past couple decades I have worked at employers who had machine shops. I was regularly in those shops making parts for work, or on occasion after hours for myself. All of the little parts I need for the many projects that appear here on Darker View.
Building an Ender 6 3D printer
My current employer does not have a machine shop leaving me no way to make parts for telescopes, electronics projects, or even little repairs around the house. Neither do I have space for a machine shop in the house. Fortunately another, more recent solution is inexpensive and quite capable, additive manufacturing.
The usual drill… A problem that can be solved by a bit of circuitry. In this case the gals in the lab were having trouble controlling the mix of gas to their cultures. They needed to feed much less CO2 to the mix, where the off-the-shelf flow gauges and needle valves became difficult to use much under one liter-per-minute.
A controller to modulate CO2 into a laboratory gas mix
Simple solution… Build a gas modulator, something that could turn on the gas some percent of the time, allowing easy control of small amounts of CO2 to the mix. A timer and a gas solenoid… Easy.
There is nothing particularly interesting about the circuitry. A seven segment display, a few switches, and a power transistor to control an external solenoid. All very basic. It is the controller that is new, at least for me. An Arduino provides the programmable part of this project.
Living with active volcanoes about becomes a bit easier if they are properly monitored. The entire island of Hawai‘i is liberally equipped with sensors of various types… Seismographs, tiltmeters, GPS stations, cameras, and gas monitors.
A remote weather and SO2 monitoring station
I came across one of these last instruments on a recent visit to Hawai‘i Volcanoes National Park, the new Kahuku Unit at the south end of the island. While walking in the gorgeous natural scenery of the park, this engineer was instantly attracted to a spindly frame of tubes standing in an old corral.
The Kahuku Cross Fence station is part of the NPS maintained Hawaii SO2 Network with stations throughout the park. The data is provided to rangers and posted on the park website to advise visitors of volcanic gas hazards while visiting the volcanoes.
