Test Driving the Magnetic Eyepieces and 3D Printing Filament Research

Magnetic eyepiece and filter attachment is awesome.

Last weekend I had a chance to test out the Drifter with the right side magnetic, the left side thumbscrews. It was a chilly but clear winter night in the low 30s that brought out a surprising number of astronomers. (Here in Oregon, we're pretty desperate for clear skies by March. This year, we were completely stumped in February.)

As someone with severe Raynaud's Syndrome--my fingers and toes get really cold really fast--I needed to keep my gloves on. And as any amateur astronomer knows, gloves make it really hard to use a telescope. Particularly, using thumbscrews, handling bare filters, and attaching 2"-1.25" adapters are difficult to the point that you often decide to skip it. You might want to zoom in on an interesting object or compare OIII and NPB filters, but you hesitate because you don't want to drop your expensive eyepieces (because gloves) or lose the thumbscrews in the grass (because gloves).

Multiply that situation by 2x with a binoscope and you realize you need a better solution.

Wow, do the magnets make a difference. Being able to grab the barrel of an eyepiece and detach it in an instant accomplishes a few things:

  1. Avoid the frustration of turning thumbscrews (with or without gloves). This is an accessibility improvement for people with fine motor challenges.
  2. Get it done much faster. Important for binoscopes.
  3. You're already holding the valuable eyepiece in your hand, so there's never the risk of the eyepiece falling out of the focuser. This is great peace of mind for anyone, no matter how methodical you might be.

The difference was tangible when I wanted a closer look at M38. I looked at the magnet side and felt "Yeah let's do this!" I looked at the thumbscrew side and felt "Maybe just cruise over to M35."

Slipping filters in and out on a whim when looking at M42 was delightfully playful. You can actually blink nebulae with filters in the light path rather than holding them precariously above the eyepiece.

That will be the experience no matter the weather: Joyfully drifting along the Milky Way as though it's a lazy river on a warm summer day.

The wait for the left side to be printed and the sky to clear up will be unbearable. Tonight I'm burning some groceries on an altar to Attilla Danko.

Other Improvements

The magnets aren't the only improvement of the new tertiary housing. The rearranged attachment system means a big reduction in cantilever on the secondary ring. Despite the fact that the new housing is attached to the old-style secondary ring via a pretty flimsy adapter bracket, it still sagged significantly less from horizon to zenith.

Also, the inner diameter of the housing surrounding the tertiary mirror is now a couple mm larger. So the tertiary can be tilted more to merge left and right eye images. I expected this to be a very modest upgrade, and had forgotten about it entirely. Turns out, it's actually a really big upgrade. Because once you bump up against the edge of the housing and you're still not merged, then you need to come up with a new plan, recentering both mirrors and starting over. This is annoying and takes time. I didn't have to do this once the whole night because of those couple extra mm of play. This is particularly impressive when you remember that the left side was sagging a lot for the reason mentioned above relative to the much stiffer right side.

Of course, merging should be largely irrelevant anyhow once both sides use the new focuser style. Stay tuned.

New Material Research

I've started looking for alternatives to carbon fiber nylon for 3d printed parts. Carbon fiber nylon is really amazing material. It's incredibly stiff, durable, heat resistant, and produces prints with a beautiful matte surface finish you'd be proud to send out into the world. It's also one of the less-challenging engineering-grade 3d filament types to print, compared to something like polycarbonate. There are some problems though: High filament cost, printer abrasion, and high-cost printer components. There's also a lot of waste involved in 3d printing, and waste from cf-nylon just goes to the landfill. The idea of recycling 3d printing waste has only just begun in earnest, and focuses only on low-end ubiquitous material like PLA, which is already biodegradable.

21st Century engineering plastics will be made from renewable sources and biodegrade. They will fit into a larger ethos of sustainability. Right now, new filaments are hitting the market made from lignin, a plant-based material that is a byproduct of biofuel production. High stiffness (3+ GPa), high strength and durability, high heat resistance, excellent surface finish, easy to print, compostable, low VOC, and very affordable. Looks like billions of years of evolution still have a leg up on us in the polymer game.

I'm ordering a spool of Greentec Pro from Extrudr in Austria to try it out. Filoalfa in Italy is another filament producer with an upcoming engineering-grade plant-based filament. It's exciting times for an already-exciting manufacturing technology.

The very first pair of binoculars was made with cardboard tubes. Ever since then, amateur telescopes have incorporated wood for its excellent material properties. It would be only too fitting if the 3d-printed parts of 21st Century telescopes were also made from plant fibers.