Oregon Star Party 2019 and Beta Drifter

It’s been a while, so there are two big things to cover.

#1, showing off the beta Drifter at Oregon Star Party.

#2, yes the beta Drifter is born--what’s been changed and how does it work?

Oregon Star Party 2019 came and left quicker than Oumuamua but what an incredible weekend! Analog Sky set up its first vendor booth and brought the beta prototype Drifter to show off a year’s worth of improvements. We also came as a whole family, with a six year old and a three year old to staff the booth and demonstrate how easy the Drifter is to use now. I’m really grateful to the whole OSP staff for putting together such a fun, welcoming, and luxurious event but shout out first to the kids tent staff for providing fun activities all weekend. They built rockets and shot them up into the air and made beautiful sun dials they can keep. This made it a great experience for everybody.

We also brought glow-in-the-dark logo t-shirts and sweatshirts to help fund the crowdfunding campaign. Shout out to Will for being our first tshirt customer--you're in on the ground floor!

Yes, the Drifter will be crowdfunded in the next couple months. This event felt incredibly successful in terms of people being excited about the scope. So the Kickstarter will fund scaling up production capacity, upgrading 3d printing quality, recruiting a brave crew of beta testers, and ordering mirrors and components wholesale. I’ll discuss this more at the end of the post and how you can help.

Overall, tons of people came by the booth to learn about the Drifter during the day and then at least 50 visitors each night spent time looking through its two eyepieces. I was pretty much stuck at the booth day and night and didn’t get a chance to listen to any talks or observe through many of the scopes I wanted to check out. Mel Bartels’ Telescope Walkabout started with the Drifter and moved on to several wildly innovative and unique scopes. Greg Lewer’s Springfield mounted 12” was so striking as an objet d’art, every time it pops back into my head (three or four times a day) the regret that I didn’t sneak away to look through it only increases. I’m just hoping it’s not a geometric or exponential increase otherwise my brain is going to explode sometime in the next couple weeks. Luckily, I did get to look through Howard Banich's silvered 28" both nights and saw a galaxy 3 billion light years distant as well as Arp 273, Hubble's Rose. Also, every view of the Veil through Mel's 25" f/2.6 simply accumulates in a partition of reality completely separate from time or space (not dissimilar from where the Prophets live in DS9), so I felt lucky to get another chance to go there.

A few themes emerged from my conversations with astronomers. The most prominent was that vision problems are severely curtailing the enjoyment many people get from visual astronomy. Several thought this might be their last OSP or that they were switching to astrophotography, not because they really wanted to do either but because their vision was making it impossible to get a good view through one eyepiece. 

Well, most of those people came back to the Drifter at night and discovered that whether they had macular degeneration, glaucoma, keratoconus, astigmatism, or some combo thereof, binocular vision was like having a time machine. They stood in line for more views or even to view the same object again. I’m supremely happy they were able to regain the joy of visual observation through the Drifter. There are a variety of binocular options for most budgets all the way up to--and far beyond! Hello Fujinon!--the Drifter. Of course, only one of those scopes has 12-16” equivalent aperture, magnetic eyepiece and filter attachment, sets up in seconds, and comes with its own custom mount and pier, but I’m getting ahead of myself. The point is, for all of you who are having trouble seeing through one eyepiece, find a way to look through two eyepieces.

Big binocular enthusiasts and OSP veterans were blown away by how easy it was to cycle a group of eight people through the scope and not have to adjust merging for anyone. One quipped that his 16” binoscope was a really good deal because he sees two of everything. IPD adjustment was intuitive for total noobs and maintained merging and focus. These views are 100% shareable. (One of the things I hear over and over again about astrophotography or the new digital scopes is the ability to share what you saw with others. There is an ancient method of sharing called "inviting others to look through the telescope with you." Early humans did astronomy this way for generations.)

People who had never looked through giant binoculars were unanimous: Viewing through two eyes was vastly more comfortable. They were really impressed with low power views of the Sagittarius Messiers and even shared my delight in tiny 30x Saturn floating amongst the stars, its rings sharp enough to identify as rings and not ears. It’s not that you can’t also see a sharp, steady Cassini Division at 150x, but the low power view is just fun. Some OSP and telescope first-timers hung around for an hour to see as many objects as I could throw at them, which was really gratifying given all the opportunities they had to look through hundreds of different scopes. I eventually told them, “Seriously, I’ll show you stuff all night but you need to go find one of those monster scopes and get a look at literally anything!”

One great tidbit of feedback was that looking through the top of the scope gives you a lot of space on either side of the body for a sketching table. I'll cop to not even pondering a sketching setup yet, but it makes sense that you have more room here than you would sidled up to a Dob.

What were my favorite views at OSP? M24 is still my favorite thing through this scope. The dark nebulae, the dark lanes swirling through and around it, the puffball NGC cluster, the sheer number of stars--there's so much beauty to take in, you can really only do it with both eyes wide open. Then chasing the trail of stars straight up to the Trifid, continuing on to the Lagoon, and then beyond into the various patches where the sky itself undulates in brightness with the glow of so many stars. The same way summer feels warm and alive and so bountiful during the day, this region of the sky matches it at night. And just as we wish to hold onto those perfect summer days for as long as possible, I'll be so sad when this sight has dipped below the horizon for another year.

The Moon might be a unsophisticated target for longtime visual observers, but listen to Mel Bartels describe Friday night in the Drifter:

"The most astounding view that I had was the moon just after sunset. The contrast, the detail and the 3D effect made for an image I will never forget."

Indeed, I can't get enough of the Moon through this scope at a variety of magnification levels either. And we're not the only ones. Like M24, I find Luna a bewildering sight through one eye, but can linger for any length of time with two eyes. If you're someone who falls into the habit of only observing around the new Moon, the Drifter can greatly increase the number of nights you get out to observe.

More and more, enjoying wide field is about composition. M42 within the whole sword. The Sombrero Galaxy, the Shark asterism, and the Stargate asterism. The Double Cluster at the edge of the field with that arc of stars shooting out the side. M8 and M20 together. Clouds drifting past the Moon as it sets behind a distant stand of Douglas Fir.

After a busy night of showing dozens of people everything around Sagittarius, the Andromeda Galaxy (with M32 and M110), the entire Pleiades, the Double Cluster, Saturn and Jupiter, the Veil, M81 and M82, and the IFN halo around M13, I had the scope to myself for a few minutes before packing it up and climbing back into the tent. Friday night I chose to end on the Ring Nebula, because 2.2 degrees is just enough to get Sulafat and Sheliak at the edges and a bright, tiny ring right between them. It's just a perfect, lovely composition. Saturday night, I wanted to be dazzled by Cygnus, so I cruised through slowly and stopped at the North American and Pelican nebulae. I tried all three filters (NPB, OIII, and H-Beta) and settled on the NPB. Fatigue kept me from exploring a little longer. Something to return to the next dark cycle.

Beta Drifter

So, what’s new on the beta Drifter? This blog has dropped some hints, and if you follow Analog Sky on Instagram, you’ve seen steady visual progress. But the cumulative effect of hundreds of improvements can’t be overstated. Let’s look at some of the big ones.

Magnetic Eyepiece and Filter Attachment

I’ve posted about this before, but in terms of enjoying your time under the stars, this feature separates the Drifter from the pack. 

Eyepiece changes in 10 seconds, filter changes in less. At one point during OSP I wanted to switch from an unfiltered wide field view to a closer view through NPB filters. Usually this means one trip to the case for eyepieces and one for filters, but I had an enthused audience and didn’t want to keep them waiting. So I grabbed all four items in one trip and held everything in one hand while installing with the other. That’s how easy it is to handle $300 worth of filters when they’re in cartridges. A stressful part of your night just completely disappears.

Secondary Mirror Collimation

The new secondary mirror mounts have no collimation adjustment of any kind. Collimating six mirrors is seen to be tricky, and puts a lot of people off scopes like this. To be fair, if you read explanations of how to perform this collimation, you are almost guaranteed to get incredibly confused. So I sought to simplify this process by designing it completely out of the equation.

Step 1: Start with f/5 primaries so that collimation is somewhat forgiving. 

Step 2: Add imaging-grade primary mounts with lock screws so that once they’re pointed in the correct direction, they never, ever move. Aurora Precision AZ-8 mounts are truly flawless.

Step 3: Mount the mounts to a laser-cut backplate so they’re perfectly aligned to one another. No mirror shifting apparatus is required.

Step 4: Lock the secondary mirrors in place with an accurately 3d printed mount that can only be connected to a laser cut secondary vane in one orientation. 

Step 5: Adhere the secondary mirrors with a 3d printed jig accurate to 150 microns. 

Now we have primary and secondary mirrors that don’t move, ever, unless you move them on purpose. This leaves us with tertiary mirrors mounted atop research-grade kinematic mounts. When image merging needs a little adjustment for whatever reason, there is an easy two-thumbscrew interface on each tertiary that allows the image x-y axes to be adjusted quickly and securely. Once it leaves the workshop, there is no collimation on the Drifter until you drop it down a flight of stairs.

Ok, sounds good in theory, but I had no idea until OSP whether removing collimation screws from the secondary would actually work. It does work. Images are aligned and rotated properly. 

In a sense, the image alignment is almost a second-order effect compared to completely eliminating collimation procedure from a binoscope.

Mirror Box and Mount

The alpha Drifter sat on a Dobsonian mount with a traditional mirror box. This worked ok, but there were two big problems. First, the rocker box took up a lot of space in the van despite being undersized and thus less-than-stable. A stable rocker box would need a diameter of 20 inches, and would have been enormous, and therefore heavier. The other problem is that the scope was too low for adults to use comfortably close to the horizon. Those Sagittarius Messiers required the observer to sit on the ground unless the whole scope was hoisted up onto a sturdy box. This is fine as low-tech solutions go, but the big sturdy box or platform requires yet more space in the van, something else to lug back and forth.

So it was time to say a fond farewell to Mr. Dobson’s cannon mount and venture out into the unknown: a completely custom alt-az mount and pier solution. Encouraged by the sturdiness of a friend’s Half Hitch Free-Turn X, I built a custom mount around the same 1” stainless shaft spec. It lives in the center of the Drifter, so it had to fit in the 80mm gap between the two primaries. 

This required a completely redesigned mirror box built of aluminum plates and tubing. The biggest advantage of this new mirror box is that the collapsible struts now telescope inside the mirror box tubes, keeping the primaries safe. Its lightweight nylon shell can take a lot of abuse in the back of a vehicle and the roll bar in front protects the tertiary assemblies without requiring any kind of lid for the whole assembly. The side struts provide convenient carrying handles. It’s about two inches wider and an inch deeper than the alpha design but the benefits outweigh the slightly larger footprint. Four feet in back allow you to set the scope on the ground any time you need to without harming the mirror cell hardware.

The pier has an adjustable 2.5” diameter aluminum column that allows about a foot (30cm) height adjustment. This makes those Sagittarius objects comfortable while seated. Right now, there is just a friction clamp to keep the column in place. When lowering the scope from high to low, you can do it with the scope attached--just keep one hand on the scope and ease off the clamp, and the whole scope just slides down gently via gravity. For raising the scope, you have to be able to lift 40 lbs (18 kg) against friction with one hand, which is much harder. So instead, it’s a quick move to pop the scope off the pier, adjust the pier, then replace the scope. It’s possible a rack-and-pinion could be added so that the scope doesn’t have to be removed, but there’s probably a reason Berlebach’s 70mm rack and pinion column adds almost $2000 to the price of their tripods. 

The pier tripod collapses down to almost nothing and provides a 20” diameter for much sturdier support than the alpha rocker box. The feet have small magnets where they touch so they click together for transport.

The mount currently uses 3d printed nylon bearings and clutches. The nylon creates some backlash but bearings will be replaced with machined ptfe. The clutches will probably need to be replaced with metal for long-term durability but they actually work much smoother than commercially available metal shaft clamps. The metal clamps tend to bind, and I don’t yet know whether this is because they clamp unevenly or because they must be aligned more accurately than 3d printing can achieve (about 150 microns). 

A few parts of the mount and pier, including the mount housing and the pier clamp, are 3d printed and the plastic alone simply doesn’t have the stiffness to keep a 40 pound OTA steady. Over the next few months, these parts will be replaced or augmented with metal fabrication to steady things up. It will be rock-solid by the time the Trapezium is up.

Mounting Mirrors to Plastic Mounts

The secondary mirrors and tertiary mirrors were mounted with a new technique. Rather than a flat mount surface with three dabs of silicone, three cylindrical holes about 15mm deep were created in the face of the mount.

Adhesives work best when the two surfaces being adhered have a high surface energy. Plastics have a relatively low surface energy compared to metal, wood, or glass. So, creating holes allows us to use a lot more silicone and therefore increase the adhesive surface area. I went a step further and added a “bone” to each hole. A smaller diameter cylinder bridges from one side of the hole to the other in a 45 degree angle and anchors the whole glob of silicone. As long as the silicone wraps all the way around the bone, it’s captive--there’s no way for it to detach from the mount besides the silicone itself tearing. All four mirrors use this technique and adhered successfully the first time. They’ve been over about ten miles of washboard and potholed gravel roads so far and seem fine. 

The alpha prototype mirrors were adhered to flat 3d printed (and sanded) nylon mount surfaces and survived a year of similar treatment on dozens of trips on forest service roads, so I don’t think plastic mirror mounts are really anything to worry about despite the lower surface energy. This new design definitely improves peace of mind though. Just because something works great doesn’t mean it can’t be improved. At this point I’m completely unworried about the secondaries falling onto the primaries so the scope has graduated from the passenger seat to the back of the van. (Yes, I kept the alpha scope in the passenger seat for an entire year through dozens of trips into the mountains to monitor how it behaved.)

Joystick Handles

The joystick handles on the UTA really, really help. Frankly, after using them for a while I'm shocked every single scope doesn't have a dedicated place to grab and move it.

People who had never touched a telescope before could easily move the Drifter around because the joystick is a familiar user interface and an unambiguous one. Every telescope is a time machine, and this feature for me is also a love note to the 1980s when I spent thousands of hours using a very similar joystick on a Commodore 64.

Interpupillary Distance (IPD) Adjustment

The beta Drifter increases the size of IPD adjustment bushings. More importantly, it adds eight geared teeth to each secondary ring. These teeth lock the two secondary rings together so that the images stay aligned better at high magnification.

This system works great. No backlash, feels good. I’m not a mechanical engineer, but the gear plugin for Fusion 360 gave me a lot of options to play with, and I assumed that having a few teeth engaged at any given time would make it work. So far so good, though I’ve designed the teeth as a separate removable piece in case they turn out to wear too quickly. They can be easily swapped out for a different material or tooth configuration. 

IPD adjustment is a very fluid thing. No, your eyes don’t wander around in your skull, but the distance you need between your eyepieces changes based on the eyepieces, whether you’re wearing glasses, and even the angle you’re approaching the eyepieces from. So one individual uses several IPD settings over the course of an observing session. 

At OSP, the system of just grabbing the eyepieces and putting them where you want worked fantastically. Friday night at least 50 people used the scope. When someone noticed the IPD setting didn’t quite work for them, they adjusted it until they exclaimed, “Oh there we go. Wow!” and it took all of two or three seconds to switch between users. Absolutely no one Friday night or Saturday night complained that they couldn’t merge the images. The Drifter's minimum distance of 58mm PD tells only part of the story. As mentioned elsewhere, there have been entire Girl Scout troops through this scope without a problem, and even my three-year-old says he sees one moon, not two.

Collapsible Strut System

The collapsible struts on the alpha Drifter just slid through their clamps into its plywood mirror box. They worked but they were jerky and could go askew, potentially running into the primary mirrors.

On the beta Drifter, the collapsible struts telescope inside the new lower struts that form the mirror box. The action is very smooth with the current 3d printed nylon bearings and will get smoother with ptfe machined bearings. More importantly, the primary mirrors are protected. 

New clamps use handles that require only a half-turn to lock each strut in place. They are effectively captive, compared to the thumbscrews in the alpha system that were harder to use and easier to lose.

The new nylon clamps stretched as they were used, requiring more and more clamping force as the weekend went on. Originally I expected to have to replace these entirely with milled aluminum components, but this week, a combination of off-the-shelf aluminum collars and a printed housing came together.

I still wonder whether carbon fiber nylon with a higher infill may have held up better, or if tweaking the clamp mating surface topology to account for the stretching could make nylon clamps a permanent part. 

At any rate, this scope collapses to a compact form factor in just a few seconds. Setup and breakdown of this scope are less than sixty seconds each.

Epoxy-Based Luminous Details

It's a small thing, but it counts. Before, glow-in-the-dark rings were added to focuser knobs and filter cartridge slots with acrylic-based paint. It was quick but not the best aesthetically. Switching to epoxy provides a perfectly smooth finish and allows me to dial in the amount of glow powder.

Things to Add

The Drifter is already set up for four dew heaters, two primary boundary layer fans, dew controller, and a LiFePo4 battery pack. This just needs to be set up and tested.

Holes already exist in the frame for hooks to hold a permanent spandex mirror box shroud. The dark observing sites around here don’t require it at all but this will definitely come in handy for urban observing.

Secondary mirror covers will be added as well for transportation and storage.

Looking Forward

The Drifter has so far undergone close to 2000 hours of design, development, and testing. My goal has been to create a new visual scope for the 21st Century and to share it with the world. Something that wouldn't just work for me, but for the widest range of people possible. Something that anyone could walk up to and use without knowing anything about the scope. Something that would set up and break down as fast and easy as a refractor with vastly more light gathering. Something that would see the universe in a whole new way. Something durable enough to survive to the 22nd Century. Heck, I think a Drifter should be aboard the Rocinante.

It's been an absolute thrill to bring the Drifter this far. The next step is to tell the world and enlist a brave crew of beta testers--fellow Drifters. A crowdfunding campaign will discover that crew, build out my manufacturing capacity, and put in wholesale orders for components like mirrors.

Not everyone will be able to become a Drifter, but Analog Sky will need support from the larger amateur astronomy community to complete this crowdfunding effort and successfully launch. My hope is that enough people share this goal of visual astronomy thriving in the years to come, not just surviving but pushing the boundaries of what's possible. Of a voice that says, "Yes, you can reach out and touch the universe, not just look at a picture of it. The muscles in your arms can take you there. You can touch three billion years ago. You and I are directly connected to things happening three billion light years away. And they are beautiful and awe-inspiring and glorifying and humbling. And they can bring you profound peace in the dead of night."

Yes, there are more ideas on the drawing board. Nothing like them currently exists.

As thanks there will be swag like t-shirts, posters, there may even be useful accessories like the collimating draw tube caps. There will definitely be glow-in-the-dark wands like the ones my six-year-old daughter sold out of at OSP. There will be a lifetime 10% discount. Most of all, you'll have heartfelt gratitude and a promise to push visual astronomy as far as it can go in the decades to come.

Right now, you can do two things that are even more important:

1. Sign up for the email list to stay updated on the crowdfunding campaign.

2. Spread the word! Post on forums, email friends! Send them back here. There will be more posts in the coming weeks going over more details that have gone into the beta Drifter, the Analog Sky vision, observation reports, and more.

Thanks again OSP, see you in 2020! Thanks to Nate at Aurora Precision for help with the campsite and advice. Thanks to Mel for the inspiration and encouragement. Thanks to Tiffany for keeping the whole family going. And thanks followers for reading through this long update. Please drop a line if you have any questions or comments!

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1 Comment

  1. Michael on August 13, 2019 at 6:08 pm

    Springload the lifter to offset the scope weight instead of adding a rack-and-pinion.

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