The View Up Here

Random scribblings about kites, photography, machining, and anything else

Archive for November, 2012

Tic Dreams

Posted by Tom Benedict on 29/11/2012

I haven’t written much about Tourette’s Syndrome recently because so much else has been going on: the cameras at work, plans for my panoramic KAP rig, and the prospect of branching out into RC AP. But my tics have been getting progressively worse.

In part I think that’s because there’s so much going on. Stress has always exacerbated my tics, and the past year has been highly stressful. Caffeine is another trigger I’ve unfortunately been over-using lately. And tics will wax and wane on their own, regardless of stressors. I’ve been in a lull for years. They were bound to peak some time.

One of my primary tics at the moment clearly evolved from another tic. The strange thing is the original tic is still there. It’s almost as if it bifurcated, or split like an amoeba. It started as a shoulder jerk (what is, in my mind, humorously referred to in the DSM as a “shrugging” motion). Over time the shoulder jerk became more and more pronounced, pulling my entire arm into the mix. Eventually my arm wound up snapping up so hard I’d hit myself in the chest with it. Or with the hand that’s at the end of my arm, rather. This persisted for some time, but it wasn’t done changing.

It’s not all that comfortable to keep smacking yourself in the middle of your chest. The truth is it hurts. So I tried to head it off at the pass by jerking my arm into my leg instead. This worked better for two reasons: First, the constant bruise in my sternum finally started to heal. And second, it’s easier to be nonchalant about occasionally smacking yourself in the leg than it is to look casual about whacking yourself in the chest. Just ask any overly stereotyped Hollywood ape!

“I’d like a latte and a croissant.” >smack< >smack< >smack<

“Um… Do you want a banana with that?”

In time the “hit myself in the leg” tic developed into its own entity. I still jerk my shoulder, though the violence of these moves has tapered off to the point that my arm is no longer so intimately involved. And now I smack my leg without involving my shoulder much at all. Voila. Two tics for the price of one.

It was thanks to the help of my wife that I came up with a less-awkward name for the “hit myself in the leg” tic. The two of us had gone into town to buy groceries. We were standing in the store near the milk, and it hit full-force. >whack< >whack< >whack< >whack< >whack< all in the space of a few seconds. She stared at me, grinned, and started smacking the backs of her hands together. I had to laugh. “Sorry, hon,” I told her, “you married a seal.” We didn’t stop laughing until we got home.

I have another new tic that didn’t evolve like the seal tic. It came out of nowhere, all on its own. For the first time in my life I have a loud vocal tic: I shout, “HO!” I’d say this is a Christmas tic, but it winds up sounding more like a pirate singing, “Yo ho yo ho” at the top of his lungs, but so drunk he forgets the “yo” part. It doesn’t have that jolly ring that Santa Claus is known for. And after yelling “HO!” several dozen times, it starts to sound like a hoarse, drunk pirate.

So far I’ve been able to avoid doing this in public. Most of the time, anyway. Most people with TS can suppress tics to some degree, but they always come back with a vengeance later. That’s how it is with this one, too. I’ll suppress it when I’m around people, but as soon as I get some time to myself it’ll come out full-force. Unfortunately I’m not always aware that I’m not alone, so I’ve had some slip-ups, mostly at work. I’ll walk into an apparently empty room, shut the door, and “HO!” “HO!” “HO!!” Then someone will poke their head around the corner and look at me in alarm. “Merry Christmas?” Weak…

As I said, it’s my first loud vocal tic. Up until now my vocals have been pretty quiet. So this is new territory for me, despite having had tics for over forty years. It’s got me stressed. (Did I mention that stress exacerbates tics? Yeah…) I’ve been assured by my co-workers that they don’t mind my tics. And for the most part they really don’t. I’ve certainly done the seal tic around them enough to know they’re cool with it. But no matter how tolerant you are, having someone suddenly yell “HO!” is bound to get a response, like, “Holy CRAP, Batman! What the @#%! was that?!” I try not to push my luck.

But the weirdest part about all this isn’t the tics themselves. It’s that I’ve started dreaming about them.

Let me back up a little. First, I don’t tic in my dreams. I don’t know if that’s typical of people with TS. It’s just how it is with me. And for the most part I don’t have good dream recall. The ones that stick are the oddball dreams. I remember years ago, when I did software development, I had a dream in source code. It was C. I came into work shaken to the core. One of the other guys asked what was going on and I said, “Um, dude, have you ever… um… like… dreamed in C?” He leaned back and smiled at me. “You mean, like in source code? A dream where you’re the code?” He knew! “YEAH!” I said. He leaned out the door and yelled, “Hey, he’s dreaming in code now!” It turns out everyone there dreamed in source code. Get that deep into writing software, and it’s apparently inevitable.

The tic dream was almost like the source code dream. It was weird! It’s not just that I was ticcing in my dream. The dream revolved around it. Kind of like a dream in which you can fly. No matter what else is going on in the dream, once you start flying you kind of go, “DUDE! I can FLY!” At that point your dream is about flying. Everything else suddenly becomes irrelevant. I don’t remember much about the tic dream except that all of a sudden I yelled “HO!” and started jerking my shoulder. The person I was talking to looked at me in surprise and said, “What’s got into you?” And for the rest of the dream I was ticcing. Seals, drunk sailors, shoulders, and all.

It wasn’t really a nightmare any more than my daily life is a nightmare. I don’t even know if I reacted in the dream. Like I said, my dream recall is pretty crappy. But I remember waking up and thinking, “That was weird,” followed swiftly by, “No, that’s a drag.” I see dreams as a biologically mandated form of escapism. But instead of getting some cool dream where I could fly, I got a dream that was… normal.

This is why I don’t watch reality TV. If I wanted reality TV, I’d watch myself. I’d rather watch some fantasy or science fiction show where one of the characters can fly. ‘Cause that’s cool!

– Tom

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Branching Out – The Bixler 2

Posted by Tom Benedict on 27/11/2012

I’ve been doing aerial photography from a kite for over five years now. I started in 2007, using a borrowed camera and a kite that was never designed to lift things. These days I’m flying a DSLR and have a quiver full of kites, all of which were chosen specifically for KAP. I’ve come a long way, and still have a long way to go. It’s as much fun to pursue now as it was when I lifted my first camera off the ground. But there’s more in the air than kites.

When I was a kid growing up in Houston, a guy lived down the street from us who worked at NASA. He was brilliant. He was also a lot of fun. He and a bunch of his friends flew RC airplanes. This was back in the day when every plane was made from balsa, and the big players in the radio market were companies like Kraft. Everything ran on gas, and a “small” plane had a wingspan wider than I was tall. To say I was envious was an understatement. But even then I knew it was way outside my budget and skill level. I got a real thrill from watching him fly. But I didn’t think I’d ever be the one doing the flying.

As with KAP, things have come a long way with RC airplanes, too. It used to take skill and patience to turn a box of balsa wood into an airplane, and crashes used to be heart-stopping affairs that often spelled the destruction of months of hard work. These days you can pick up a ready-to-fly or almost ready-to-fly plane made out of foam that can be glued back together after a crash, and be flying again within the hour. Engines used to cost more than two years of allowance. These days a complete brushless DC power system might cost a quarter of that. Servos and radios used to be big bulky affairs that cost more than my body parts were worth on the black market. These days a complete Tx/Rx and servo set cost less than the plane they go in. In short, RC airplanes have finally become affordable for guys like me. So I asked for one for Christmas.

I don’t think it’ll take the place of KAP. For starters most of the KAP work I do relies on the camera being stationary in the air. I can do aerial panoramas if the camera is sitting still. Just spin it in place and trip the shutter. If the camera is on a moving platform like an airplane, that’s a lot harder to do. I also enjoy flying kites too much to ever stop now. Even when conditions aren’t right for photography, I’ll often put a kite in the air just so I can hold the string and smile at the wind. And really that’s what I want to get into RC airplanes for: to have fun. Because if watching my neighbor all those years ago is any indicator, they’re a LOT of fun.

But that’s not to say I’ll never stick a camera in a plane. Cameras, too, have come a long way since I was a kid. These days you can stick a tiny brick of a camera in an airplane and get a high quality video of the flight. Thousands of people are populating their airplanes with first-person view cameras and video downlink systems, GoPro nose cameras, tiny gumstick cameras stuck out on the wing tips or on the landing gear, etc. At some point curiosity will get the better of me and I’ll give it a try. So I wanted my first plane to give me enough room to grow.

All of which made for a fairly broad set of requirements for the plane. I wanted it to be a good beginner’s plane. I wanted it to be cheap and easy to fix. And I wanted it to have enough capacity to let me eventually cram a camera into its guts. I wound up asking for the Bixler 2 from Hobby King. It’s a 1.5m wingspan motor glider that was designed with FPV and cameras in mind. An excellent video from Flite Test discusses the origins of the Bixler 2, and the similarities and differences between it and its predecessor, the Bixler. The biggies are that the Bixler is smaller and faster, but harder on its battery. The Bixler 2 has a wider wingspan and a slower motor driving a larger prop, which leads to its longer battery life. The Bixler 2 also incorporates flaps, though you have to supply your own servos to use that option. (Yes, I asked for the flap servos as well.) The whole thing is molded from EPO foam, so repairs are fairly straightforward.

Now for the kicker: The Bixler 2, flap servos, ESC, three LiPo batteries, a LiPo charger, and an RC glider backpack all cost less than my G-Kites Dopero. (This helped sell the idea with she who actually orders my presents.) So much for RC airplanes being out of my price range. All I need now is a donor camera to stick in it. (Did I really say that?) No, seriously… First I have to learn to fly.

– Tom

Posted in Kite, Kite Aerial Photography, RC Airplanes | 4 Comments »

Reasons to Enjoy the Weekend

Posted by Tom Benedict on 17/11/2012

I thought I was going to spend the week finishing the cameras at work. A nice, quiet, uneventful week. Boy was I ever wrong. A series of projects and emergencies had me and my co-workers at the summit and on the go almost the entire week.

It started with an instrument exchange. These days we have three primary instruments on the telescope: Megacam, our visible light imager, WIRCAM, our infrared imager, and Espadons, our visible spectropolarimeter. Typically two of these will be used each month. When the moon is less than half full – what we call dark time – Megacam is typically on the telescope. WIRCAM and Espadons are less sensitive to moonlight, so they are our bright time instruments. One or the other will be on any time the moon is more than half full.

This was one of the exceptions. Our adaptive optics bonnette (AOB) was at the cassegrain focus of the telescope along with one of our smaller infrared imagers, KIR. AOB/KIR was slated to be removed and Megacam installed. The actual exchange went well. The rest went horribly wrong. Two of us had just finished up a bunch of work on Espadons the week before. The only step left was to put all the covers back on and check the instrument out for the sky. Once the exchange was done we popped all the covers on and ran a quick hardware check. We’ve run hundreds of these over the years without incident. This time it failed.

It turned out one of the actuators on the instrument had died. We spent the next two days coming up with a work-around while our machinist rebuilt the actuator. By the end of the second day we had our temporary fix – a micrometer head bolted to a block of aluminum – all sorted out. We also had the rebuilt actuator re-installed and checked out for the sky.

Meanwhile we were slated to pull WIRCAM out of its upper-end so that another adaptive optics system could be tested on sky. This took the better part of a day, and involved a fair bit of stress because we couldn’t let the camera warm up during the move. As soon as it was out of its upper-end, it was wheeled down to one of our labs where we hooked it back up to its cryogenic system. It never came above 85 degrees Kelvin.

While all this was going on, other members of the team were working on a possible problem with our dome shutter – the big door that has to open every night so we can observe, and that has to close every morning to keep out the sun, the rain, the wind, and the dust. Just as we finished getting WIRCAM bedded down in the lab, I was called on to help with the shutter.

So at 4pm on my third day in a row at 14,000′ of altitude, I found myself fifty feet above the ground staring across space at Megacam while my boss was squeezing himself into a crawlspace in the ceiling barely big enough to fit his body so he could take pictures of the shutter drive units. “Hey!” I thought, “I wonder if I could make a credible HDR photo using a cell phone.” So I pulled out my phone, braced it as best I could against a nearby railing, and did a five frame, five stop HDR stack.

Megacam on CFHT

It turned out pretty well, considering the contrast range, the high pressure sodium lighting, and the fact that I didn’t have a tripod, beanbag, or any other real way to steady the camera. All in all I’m impressed with the cameras that are being shoehorned into cell phones these days. It’s no replacement for a DSLR or even a good compact camera. But it’s honestly pretty darned good. I thought it particularly fitting that I was photographing what was at one time the largest digital camera in the world, using a camera so small it fits inside a cell phone.

And in case you’re wondering how I got to be fifty feet off the ground to make this picture, this is what the view was looking straight down:

Where I Was

Yup, that’s my foot. And the square yellow column just to the left of my foot is all that’s holding me up. For the part of the shutter my boss needed to access, this is the only way to get there.

And maybe this explains a couple of things:

First, I know why I like the perspective KAP offers. It’s a fascinating height to work from. I enjoy going up in the lift just to get that view. Tired as I was, I jumped when my boss said he needed someone to go up with him. It’s the closest I can come to seeing what a KAP rig would see. Things are close enough to look familiar, yet far enough away to give the viewer a fresh take on the world.

Second, it just reinforces how glad I am not to have a fear of heights. It’s amazing how much of my working life here has been spent strapped into a fall harness.

Finally, it’s just one more reason to enjoy the weekend. Even when I think I have a pleasant uneventful week ahead of me, this is typically what happens. Par for the course when working at a telescope.

So what’s in store for next week? I HAVE NO IDEA! And that’s par for the course, too.

– Tom

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Back to the Panoramic KAP Rig

Posted by Tom Benedict on 14/11/2012

I got my pano rig out again over the weekend, flying it at the south end of Hapuna Beach. I flew my Canon T2i and 18-55mm lens set at 18mm. It was… less than satisfying. But I think it’s pointing me in a direction I was already heading, so in a way it was a good experience.

Two problems jumped out. First, using the 18-55mm lens at the wide end makes for fuzzy pictures with horrid chromatic aberration. In the past I’ve flown it set to 24mm. It performs far better at this focal length. I just wish I could use its full wide angle capabilities. Pity. But right now I can’t afford a higher quality wide angle lens – prime or zoom.

The second had to do with the pano rig itself. With the exception of one orbit of the rig, in every other orbit it had gaps in the sequence when the rig was pointing toward the beach. It’s as if the servo sped up, slowed down, and then sped up again at some other point of the rotation. I couldn’t stitch the images because there wasn’t enough overlap between images. In the worst cases there wasn’t ANY overlap.

This is simply unacceptable. What I wanted when I built this was a KAP rig I could put in the air and without fail come back with good solid sets of images I could stitch every single time. I’m not getting that. So obviously something has to change.

My original plan when I built this was to stick a relative shaft encoder on the pan axis. That way I could drive the rig to a real position, trigger the shutter, then rotate to the next real position. I punted on this when I saw how consistent my pan servo was. I probably shouldn’t have. It was good, but obviously it wasn’t good enough.

My plan now is to add a plate on top of the pan axis gear. The plate will have a series of small rare-earth magnets embedded in it. I’ll then hot glue a hall-effect sensor to the gear guide so it’s positioned directly over the ring of magnets in the plate. The Micro Maestro I’m using as a rig controller can be configured to use one of its I/O pins as an analog to digital converter. I’ll wire the hall-effect sensor to the ADC input and use that to sense the position of the magnet plate. That, in turn, will give me an encoder on the pan axis that I can use to position the rig for each exposure. The plate and hall-effect sensor should also stay inside the existing envelope of the rig. No extra things protruding out, and only one extra wire. It should have a minimal impact on the rig itself.

I hope this works. I’ve got a lot of work still to do on rig stability. But the rest of the rig has to work first. Then it’s time for post-sunset panoramic KAP!

– Tom

Posted in Engineering, Kite Aerial Photography | 9 Comments »

More Camera Work

Posted by Tom Benedict on 10/11/2012

The new parts for the cameras worked perfectly. In the process I also figured out why the holes on the first set were the wrong size. To make a long story short, I left some stock on the parts for a finish pass of the cutting tool, but didn’t actually include a finish pass in the toolpath. So the holes were precisely 0.0118″x2 too small. (I left 0.0118″ for finishing.) Sometimes the software is too smart for the operator…

But the new parts work great!

CFHT Sitelle Camera Assembly

I got most of the anodized bits assembled earlier in the week. From left to right are the anti-vibration towers for the cryo coolers, the preamplifier enclosures, the cryo cooler hose supports (hiding behind my coffee cup), the vacuum flange clamps for the valve and vacuum gauge, and finally the support rods for the anti-vibration towers for when the camera is off vacuum.

But the real work this week is in the foreground. On the left side are the getter bodies and their caps. On the right are the partially assembled “three ring circuses” that provide the thermal isolation necessary to cool the detector down to -100C while the outside of the camera is still a relatively toasty 0C. Those parts I had to re-make? Those light colored tabs in the three ring circuses are the new parts. They fit perfectly.

But not everything went so smoothly. The three ring circus sitting right in the middle is fitted out with a dummy detector PCB, but it’s not actually attached to the rest of the parts. Why? Because when I placed the nut and bolt order from hell for these cameras, I left out the screws that hold the detector onto the cold part of the camera. I sent out a new nut and bolt order as soon as I realized that, but now it’s a game of hurry up and wait.

In the meantime, though, there’s plenty more to do. So today I built out one of the getters and stuck it into a test cryostat we have sitting in the lab. It’s pumping down now, and should be ready to turn on Tuesday morning. The test for this thing is about as brute-force as you can get: With our PCC cooler loaded with PT-14 gas, our previous getter design would pull the vacuum on the test cryostat down to the high 10x-7 torr range. If this one can’t beat that performance, I have to change the design. It’s that simple. My back of the envelope calculations say it should be able to pull about 1.6x harder than our previous getters, and have a much higher overall capacity. So it shouldn’t be a subtle effect. If it is, it’s back to the drawing board.

There are only a handful of parts left to make for these cameras. Providing the getter testing goes well and the new screws let me finish assembling the camera’s innards, I may be back to serious kite flying in the next couple of weeks. I can’t wait.

– Tom

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Back to the Cameras

Posted by Tom Benedict on 03/11/2012

I haven’t posted anything recently because my life was almost entirely out of my hands for a while. Since my last post I’ve been cutting down four of my trees every spare moment I’ve had from work. And when I’ve been at work I’ve been working on two of our existing instruments in addition to working on the new one we’re building. In the middle of all this my son fell behind in his school work, so I’ve been a tutor as well. Non-stop action!

And not much sleep. But my son is caught up with his work, my trees should be done this weekend, and the servicing on the two instruments at work is nearly complete. That just leaves the cameras for the new instrument. As luck would have it, there has been progress on that as well!

CFHT Sitelle Parts Anodized

The parts came back from the anodizer! And the color? Love it!

There’s still a good bit of work to be done on the cameras, though. For starters, you can’t have an anodized surface inside a vacuum vessel. So our machinist at work is going to take the two camera bodies, machine off all the anodizing on the insides while he’s doing all the finish-machining, add all the side ports, and then either he or I will polish every internal surface to a high shine. This isn’t so much for looks (though it does look cool!) It’s to minimize the surfaces to which gases can stick when we pump the cameras down to hard vacuum.

In the meanwhile our machinist has been making most of the other camera internals. He just finished those today as well, so I’m test-fitting everything to make sure it goes together as it’s supposed to. And therein lies the rub, so to speak. Already I’ve found one set of parts I made that had the wrong size screw holes in them. I needed to re-make one set, anyway, so I’m going to make entirely new parts with the right hole size so they’ll mate with the parts our machinist made. Then there’s the whole set of experiments to characterize the getter. And then the experiments to characterize the cryogenics. And then the pump-down and hold-time tests. And then fitting the actual detectors. And and and… Yeah. Still some work to be done.

But we’re a lot closer now! And maybe, just maybe, I’ll get a chance to fly a kite soon.

– Tom

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